SpatialâTemporal Dispersion of Aerosolized Nanoparticles During

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Spatial-temporal Dispersion of Aerosolized Nanoparticles During the Use of Consumer Spray Products and Estimates of Inhalation Exposure Jihoon Park, Seunghon Ham, Miyeon Jang, Jinho Lee, Sunju Kim, Sungkyoon Kim, Kiyoung Lee, Donguk Park, Jung-Taek Kwon, Hyunmi Kim, Pilje Kim, Kyunghee Choi, and Chungsik Yoon Environ. Sci. Technol., Just Accepted Manuscript • Publication Date (Web): 25 Apr 2017 Downloaded from http://pubs.acs.org on May 1, 2017

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Environmental Science & Technology

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Spatial-temporal Dispersion of Aerosolized Nanoparticles During the Use

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of Consumer Spray Products and Estimates of Inhalation Exposure

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Jihoon Park,1 Seunghon Ham,2 Miyeon Jang,1 Jinho Lee,1 Sunju Kim,1 Sungkyoon Kim,1,2

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Kiyoung Lee,1,2 Donguk Park,3 Jungtaek Kwon,4 Hyunmi Kim,4 Pilje Kim,4 Kyunghee Choi,4

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Chungsik Yoon 1,2,*

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1

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University, Seoul, Republic of Korea

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2

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Seoul, Republic of Korea

Department of Environmental Health Sciences, Graduate School of Public Health, Seoul National

Institute of Health and Environment, Graduate School of Public Health, Seoul National University,

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Department of Environmental Health, Korea National Open University, Seoul, Republic of Korea

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Risk Assessment Division, Environmental Health Research Department, National Institute of

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Environmental Research, Incheon, Republic of Korea

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* Corresponding author:

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Prof. Chungsik Yoon, Department of Environmental Health Sciences, Institute of Health and

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Environment, Graduate School of Public Health, Seoul National University, Gwanak-ro 1, Gwanak-

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gu, Seoul 08826 and Republic of Korea.

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E-mail) [email protected]

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Tel) +82-2-880-2734

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Fax) +82-2-745-9104

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Manuscript word count: 6,982

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Abstract word count: 250

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Number of Tables: 7

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Number of Figures: 4

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ACS Paragon Plus Environment


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Abstract

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We evaluated the spatial-temporal dispersion of airborne nanomaterials during the use of

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spray consumer products and estimated the level of consumer inhalation exposure. A total of eight

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spray products including five propellant and three pump types were selected to evaluate the dispersion

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of airborne nanoparticles across time and space in a cleanroom which could control the background

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particles. Four products were advertised to contain silver and one contained titanium nanoparticles,

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while three products were specified no ENM but as being manufactured through the use of

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nanotechnology. We used direct-reading instruments with a thermodesorber unit to measure the

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particles (number, mass, surface area), as well as filter sampling to examine physicochemical

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characteristics. Sampling was conducted simultaneously at each location (1 m, near-field; 2, 3 m, far-

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field) by distance from the source. We estimated the inhaled doses at the breathing zone, and the doses

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deposited in each part of the respiratory tract using the experimental data and mathematical models.

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Nanoparticles released from the propellant sprays persisted in the air and dispersed over a large

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distance due to their small size (1,466-5,565 particles/cm3). Conversely, the pump sprays produced

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larger droplets that settled out of the air relatively close to the source, so the concentration was similar

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to background level (< 200 particles/cm3). The estimates of inhalation exposure also suggested that

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exposure to nanoparticles was greater with propellant sprays (1.2×108±4.0×107 particles/kgbw/day)

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than pump sprays (2.7×107±6.5×106 particles/kgbw/day). We concluded that the propellant sprays

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create a higher risk of exposure than the pump sprays.

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Keywords: Engineered nanomaterial, spray, inhalation exposure, near-field, far-field, inhaled dose,

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deposited dose

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Graphical Table of Content:

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Introduction

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Nanotechnology is an emerging multidisciplinary science that involves the synthesis of

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molecules in the nanoscale size range.1 Because the unique physicochemical and biological properties

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of molecules at this size range serve to enhance versatility and efficacy in product development,

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engineered nanomaterials (ENMs) have been incorporated into a wide range of products. However,

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research into the potential effects of ENMs on both human health and the environment is still

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ongoing.1-3

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Nanotechnology-based consumer products have been developed for commercial use over the

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past decade, and many have already migrated from laboratory benches into store shelves and the

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online market.3-4 The number of consumer products containing ENMs has increased globally from 54

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products in 2005 to 1,814 products in 2014, with a consequent increase in the potential for consumer

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exposure.3 ENMs in consumer products are usually embedded in forms such as nanostructured bulk,

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nanostructured surfaces, surface-bound particles, and suspensions in fluids or solids.3

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Consumer spray products contain ENMs in a variety of fluids. They comprise the largest

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ENM product category (about 30% of all products), and are also regarded to pose the most critical

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risk to human health through direct inhalation.5-7 In areas where these spray products are used,

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inhalation is generally considered the primary exposure route because the matrix including ENMs can

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be aerosolized into small droplets that can easily penetrate lung tissue.8 The health risks can be

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assessed based on nanoparticle properties such as size distribution, concentration, chemical

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composition, shape, and surface area/functionality.5, 9

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The behavior of ENMs released into the air during product use has a decisive effect on

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inhalation, and it can vary between aerosol products by nozzle type (propellant vs. pump) and

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incorporated solvent (organic solvent-based vs. water-based).5 Propellant sprays generally produce

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much smaller aerosolized particles than pump sprays, and the volatility of mixed solvents is the main

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factor influencing the behavior of nanoparticles.10 Considering their characteristics, the behavior of

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airborne ENMs across time and space during and after use is important for consumer exposure

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assessment. Information about exposure based on the actual use of ENMs-containing products is also 4


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essential for investigating the potential health risks associated with the use of nanotechnology-based

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consumer products

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Previous studies have examined the risk of exposure to ENMs through the use of consumer

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products, but only limited data are available concerning ENM emission and consumer exposure

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resulting from the use of spray products.10-15 There are no international regulations on ENMs in

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consumer products, with the exception of EC Regulation 1123/2009 for nanolabeling in ENM-

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containing cosmetics.16 Thus, our current understanding of the hazards caused by ENM product use is

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uncertain, and there is no way to estimate how many ENM-containing products are distributed in the

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marketplace. Because public concern about the hazards of consumer products is increasing, further

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studies on ENM-containing products are urgently required.

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The objectives of the present study were to investigate the spatial-temporal dispersion of

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airborne ENMs during the use of spray products and to estimate consumer exposure via inhalation

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using exposure factors.

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Methods

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Schematic design

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This study focused on the airborne dispersion of released ENMs across time and space during the

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use of consumer products through a realistic experiment. Next, inhalation exposure was estimated

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using both experimental data and exposure factors. The experiment consisted of real-time monitoring

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using direct-reading instruments (DRI) and a time-weighted sampling method for offline analysis. The

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methodological scheme of this study is shown in Fig. 1.

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Figure 1. The methodological scheme of this study.

Consumer products

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Spray products were purchased over the internet market based on 2015 domestic sales rankings.17

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We selected these products on the assumption that they would be widely used among consumers on a

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daily basis. Table 1 lists the basic characteristics of the selected products. A total of eight spray

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products, including both different propellant types (5 products) and pump types (3 products), were

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selected to evaluate the dispersion of airborne ENMs. The products were intended for use as

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deodorizer for air conditioner, cleaners for household devices or surfaces, air deodorizer, air

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fresheners, and coatings for functional clothing. 6


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According to the Material Safety Data Sheet (MSDS) supplied by each manufacturer, all

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products were advertised as either containing ENMs or as being manufactured through the use of

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nanotechnology. Silver nanoparticles (AgNP) were present in Products A, B, C, and H, while Product

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G contained titanium dioxide (TiO2). Other products (D, E, F) did not advertise the use of

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nanomaterials on the label or MSDS, and only claimed the use of nanotechnology during production.

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A total of six products used mixtures of organic solvents (ethyl alcohol, diethylenetriamine, etc.), and

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only one product used distilled water as a solvent. Product G contained no detailed information on its

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contents, except for TiO2 and water, and we were unable to acquire the MSDS from either the supplier

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or the manufacturer.

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(Table 1 here)

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Experimental set up and measurement

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Cleanroom set up

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The experiment was conducted in a cleanroom (nominal class 1,000)18 with a volume of 40

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m3. The cleanroom could limit the indoor background particles to less than 1,000 particles/ft3 when

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measuring 0.3 µm using a ventilation system equipped with a high-efficiency particulate air (HEPA)

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filter. When the ventilation system was used, purified air was supplied to the room through inlets

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located on the ceiling. The air could leave the room through outlets on the walls (Fig. 2). The

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ventilation system was used for at least an hour until the background level was minimized (less than

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200 particles/cm3 by SMPS), and then turned off. We confirmed that there was no artificial air flow in

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the clean room and conducted background sampling an hour before spraying. The researcher wore

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appropriate cleanroom garments, and passed through an air-showering room to minimize the

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introduction of outside particles into the cleanroom. The indoor temperature and the relative humidity

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were also monitored consistently to maintain optimum conditions using a real-time digital thermo-

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hygrometer (Model TR-72U, T&D Inc., Japan). The indoor environmental conditions in the

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cleanroom were monitored and kept constant throughout aerosol sampling. The indoor temperature

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and the relative humidity (RH) were maintained at 27.4 ± 0.9°C and 38.4 ± 3.8% RH, respectively,

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during the sampling periods.

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Figure 2. The sampling diagram in the clean room. Air circulation was done before experiment and was off during experiment. Instrumentations and measurement of airborne ENMs The spatial-temporal dispersion of nanoparticles was assessed using DRIs to measure

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particle size distribution, concentration, surface-area, and mass. In addition to real-time monitoring,

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we conducted filter sampling to identify the physicochemical characteristics of sprayed nanoparticles.

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The sampling diagram in the cleanroom set up is shown in Fig. 2. The DRIs and filter

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sampling devices were placed in each sampling location. We divided the exposure area of the clean

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room into near-field (< 1 m) and far-field (2, 3 m) areas according to the distance concepts provided

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in previous studies. 5, 19-20 The DRIs, including an SMPS-1, OPS-1, AeroTrak-1, and Dust-trak, were

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located at 1 m (near-field) from the sprayer to evaluate the exposure level close to the source. In the

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far-field areas, an SMPS-2, OPS -2, and AeroTrak-2 were located at 2 m, and an SMPS-3 was located

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at 3 m from the sprayer. These devices were used to characterize spatial dispersion, as well as the

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potential for bystander exposure at greater distances. All real-time monitoring and filter sampling

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were conducted simultaneously at each location in the cleanroom.

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All real-time data recording intervals were set to every minute, and the characteristics of

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each instrument used for real-time monitoring were as follows: (1) Scanning mobility particle sizers

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(SMPS, Model Nanoscan 3910, TSI Inc., Shoreview, MN, USA) and an optical particle spectrometer

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(OPS, Model 3330, TSI Inc., Shoreview, MN, USA) were used to measure the particle concentration

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and size distribution in the range of 10–10,000 nm (SMPS; 10–420 nm, OPS; 300–10,000 nm). (2)

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Surface area was monitored using a nanoparticle aerosol monitor (Model Aero-Trak 9000, TSI Inc.,

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Shoreview, MN, USA) that could measure up to 10,000 µm2/cm3 in the range of 10–10,000 nm. (3) A

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dusttrak (Model 8533, TSI Inc., Shoreview, MN, USA) was used to measure the mass between 0.001

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to 150 mg/m3 for particles from 0.1–15 µm using a light-scattering sensor. In addition, polycarbonate

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(PC, diameter 37 mm, pore size 0.4 µm, SKC Inc., Eighty Four, PA, USA) filters and mixed cellulose

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ester (MCE, diameter 37 mm, pore size 0.4 µm, SKC Inc., Eighty Four, PA, USA) filters were used to

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collect airborne particles using a high volume pump (Model Air Check XR5000, SKC Inc., Eighty

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Four, PA, USA), with a flow rate of 2.0 L/min, and to identify particle size, morphology, chemical

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composition, and metallic elements at all sampling locations.

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After background sampling for an hour after the ventilation was turned off, each product was

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sprayed. Each product was shaken at least 10 times manually to disperse the ENMs in the liquid

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evenly prior to spraying, and then sprayed into the air in one direction for two seconds, followed by a

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one second pause, four times (i.e., four cycles of 2 sec sprays and 1 sec pauses). After spraying,

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sampling was conducted for about two hours until particle concentrations decreased to the background

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level. Individual products were also weighed before and after spraying using a weighing balance to

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calculate particle characteristics per released mass at each metric (particle number, surface area, and

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mass). Spraying experiments were repeated three times for each product to capture the variation

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among sprays, except for Products F (one experiment) and G (two experiments).

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Aerosolized solvents with airborne ENMs can affect real-time monitoring results.10 In the

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present study, a thermodesorber unit installed in front of the DRI inlets was used to minimize

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interference with droplets surrounding ENMs, such as water and organic solvents. The

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thermodesorber consisted of a heating jacket set to 200°C and an adsorption tube filled with charcoal 9



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to remove water and organic compounds via vaporization and chemical adsorption. The aerosols

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passed through the sampling tubes, and the dried nanoparticles flowed into each instrument inlet for

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monitoring. Prior to the experiment, we assessed the effect of the thermodesorbers using two SMPSs

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under the same conditions, and found that the concentration of particles was 84.5% lower when the

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thermodesorber was used for aerosol sampling (Fig. S1). To identify the possible particle losses

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through adhesion to the surface of each thermodesorber part, we also conducted wipe sampling as a

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preliminary experiment. Two SMPSs were turned to collect the samples, and Product A, containing

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AgNP, was sprayed for five seconds in the cleanroom. At this time, SMPS with and without

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thermodesorbers were compared. Each sample was collected using a swab and spread on a carbon-

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coated 400 mesh copper grid (Model 01824, TED PELLA Inc., PO, USA) for analysis using a high-

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resolution transmission electron microscope (HR TEM, Model JEM-3010, JEOL Inc., Japan)

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equipped with an energy-dispersive X-ray spectrometer (EDX, Model AZtecOneXT, Oxford

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Instruments Inc., UK).

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Analytical methods for ENM identification Filter samples were analyzed to determine the characteristics of ENMs using an inductively

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coupled plasma mass spectrometer (ICP-MS, Model NexION 350D, Perkin Elmer Inc., Houston, TX,

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USA) and a field emission-scanning electron microscope (FE-SEM. Model MERLIN Compact,

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ZEISS Inc., Germany) with an EDX (Model NORAN SYSTEM 7, Thermo Scientific Inc., USA).

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ICP-MS analysis was used to detect the presence of target elements such as silver (Ag) and titanium

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(Ti). The organic matrices in each MCE filter were removed through acid digestion using 5 mL of

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aqua regia solution in combination with hydrochloric and nitric acid (3:1). Next, each sample was

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digested at 180°C overnight on a multi hot plate (Model ECOPRE, OLDLAB Inc., Korea), and

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distilled water was added to reach a total volume of 40 mL in a Falcon tube. The quantification of

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target ingredients was conducted using calibration curves from multi-element standard solutions

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including the major metallic ingredients, i.e., Ag, Ti, aluminum (Al), chromium (Cr), manganese

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(Mn), iron (Fe), nickel (Ni), copper (Cu), zinc (Zn), lead (Pb), cadmium (Cd), and magnesium (Mg) 10


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(Multi-element calibration standard 3, N9301720, Perkin Elmer Inc., Houston, TX, USA). The limit

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of detection (LOD) of each ingredient was estimated from the threefold deviation of seven replicates

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at the lowest concentration (0.1 ppb).

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The physical characteristics of ENMs, including size, morphology, coagulation state and

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chemical composition, were analyzed using the FE-SEM/EDX. A piece of PC filter was attached to an

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aluminum holder using carbon tape and pretreated with platinum coater (Model MSC-101, JEOL Inc.,

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Japan) for 180 seconds. Morphology, size, and aggregation/agglomeration were analyzed under an

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acceleration voltage of 2 kV and the chemical composition was identified at 15 kV in combination

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with the EDX.

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Estimation of inhalation exposure

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To estimate consumer exposure via inhalation during spray use, we calculated the inhaled

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doses in the breathing zone by particle size and deposited doses throughout the respiratory tract using

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a mathematical model described in other studies.14, 21-22 The particle concentrations acquired from both

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SMPS (10–420 nm) and OPS (300–10,000 nm) data were merged using Multi-Instrument Manager

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2.0 (MIM-2, TSI Inc., Shoreview, MN, USA) software provided by the manufacturer. These data

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were also converted to mass and surface area figures based on particle density. Density was calculated

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according to the ENM material; for example, Ag was 10.5 g/cm3 for AgNP-containing products, and

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Ti was 4.5 g/cm3. When the ingredients of nanotechnology-based products were unclear (i.e., when

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there was no description of the target ENMs on the product label or MSDS), the density was assumed

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to be equal to air density (1.2 g/cm3).

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The inhaled doses and the deposited doses were calculated for each metric, including particle

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number (particles/kgbw/day), mass (ng/kgbw/day), and surface area (µm2/kgbw/day) per unit body

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weight for a day. The inhaled doses were calculated using each particle metric according to the ranges

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of particle diameter (Dp) and assigned to subgroups as follows; Dp0.011-0.1, Dp1.0-2.5, Dp2.5-5.0, Dp5.0-10.0.

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The deposited dose was also separated according to part of respiratory tract, nasal region (NR),

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tracheobronchial region (TR), and alveolar region (AR). The Korean Ministry of Environment 11



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(KMOE) has provided exposure factors that are similar to the United States Environmental Protection

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Agency (US EPA) exposure factors, and some of them were used to estimate the inhalation exposure

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in the model (Table 2).23 The average body weight and inhalation rate of Korean adults were used as

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common factors, and individual exposure factors such as duration of use, main using location, and

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exposure time were also used in the model. Among the using location, the balcony was arbitrary

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selected as a using location for coating spray (Product D, E) because the precaution on the label just

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indicated a well-ventilated area. The equations for calculating the inhaled dose and the deposited dose

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are provided in the supporting information (SI).

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(Table 2 here)

Data analysis We conducted a statistical analysis on all data acquired from real-time monitoring. We used

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descriptive statistics to compare the levels of particle concentration during the use of each spray

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product. A Shapiro-Wilk test indicated that the data followed a log-normal distribution, and we

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therefore used log-transformed data for statistical analysis. We derived geometric means (GM) and

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geometric standard deviations (GSD) for metrics such as particle number, surface area, and mass, as

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well as sampling location. Arithmetic means (AM) and standard deviations (SD) were calculated for

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inhalation exposure estimates, because the results were acquired from experiments conducted in

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triplicate. A one-way analysis of variance (ANOVA) was conducted to compare particle concentration

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by spray nozzle type (propellant vs. pump), distance (near-field vs. far-field), and elapsed time (before

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vs. after spraying). We used a post-hoc Tukey test to determine the differences in concentration by

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elapsed time after spraying. All statistical analyses were conducted using SAS 9.4 (SAS Institute,

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Cary, NC, USA).

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Results

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Experimental conditions

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The peak concentration of nanoparticles without the thermodesorber was much higher

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(27,791 ± 9,435 particles/cm3) than the peak concentration when the thermodesorber was used (4,302

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± 433 particles/cm3). This trend was consistent until the level of sprayed aerosols decreased to that of

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background concentration (about 180 min). We confirmed that there were no target ENMs on the

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wipe samples taken from the inner surface of the thermodesorber using a TEM analysis. Therefore,

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we assumed that the aerosolized solvent was effectively removed and that particle loss due to the

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thermodesorber was negligible. See the TEM images in Fig. S2 of SI.

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Airborne spatial-temporal dispersion of ENMs during the use of spray products

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Spatial-temporal dispersion of nanoparticles in the cleanroom The particle concentrations during spray product usage varied significantly according to time,

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space, and nozzle type. Table 3 summarizes the particle concentrations before, spraying, and after

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spraying of each spray product. It was expected that peak exposure would be occurred for initial a few

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minutes during product use, thereby ‘spraying’ indicates the duration of exposure time for initial 10

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minutes during spraying and the ‘after’ indicates the duration of time remaining until the

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measurement was complete.

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The background concentration of nanoparticles (≤ 100 nm) was below ~200 particles/cm3

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before spraying at each distance in the clean room. After spraying, the nanoparticles emitted from

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each spray product differed substantially based on nozzle type and distance. With propellant sprays, a

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number of nanoparticles appeared rapidly in the near-field area and dispersed to the far-field area

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three minutes after spraying.

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The geometric means (GMs) of nanoparticle concentrations ranged from about 3,160 (GSD;

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1.4, Product D) to 11,227 (GSD; 1.2, Product A) particles/cm3, and increased to a peak of 136 times

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the background level at 1 m from the source. The nanoparticles in far-field areas also increased from

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about 1,392 (GSD; 1.4, Product D) to 9,454 (GSD; 1.2, Product A) particles/cm3 at a distance of 2 m 13



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from the source, and from about 1,675 (GSD; 1.3, Product E) to 9,347 (GSD; 1.1, Product A)

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particles/cm3 at a distance of 3 m. The proportion of larger particles, from 100 to 420 nm in size, also

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increased. Particles from 100 to 420 nm in size were much more abundant in far-field areas;

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conversely, nanoparticles were dominant in near-field areas. The GMs of the concentrations for

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particles 100-420 nm ranged from about 544 (GSD; 1.5, Product A) to 1,257 (GSD; 1.6, Product D)

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particles/cm3 in near0field areas, and from about 426 (GSD; 1.3, Product A) to 1,609 (GSD; 1.8,

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Product D) particles/cm3 in far-field areas.

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The surface area and mass metrics followed similar trends to that of the particle

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concentration. Particle surface area per cubic centimeter was measured using two Aerotraks at 1 and 2

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m from the spray source. The background surface area concentration of nanoparticles (≤ 100 nm) was

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also maintained at 0.1–1.6 µm2/cm3 in the cleanroom before spraying, but increased to between 6.5

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(GSD; 1.4, Product D) and 16.7 (GSD; 1.2, Product A) µm2/cm3 in near-field areas. Contrary to

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particle number concentration, the particle surface areas per cm3 were much higher in far-field areas,

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ranging from 20.9 (GSD; 1.3, Product D) to 34.1 (GSD; 1.3, Product A) µm2/cm3. The mass of

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emitted particles was only monitored in near-field areas, and the background concentration was less

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than 3.0 µg/m3. After spraying, the airborne particle mass for individual propellant sprays increased to

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between 61.1 (GSD; 1.5, Product A) and 162.4 (GSD; 1.5, Product E) µg/m3.

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For pump sprays, particle concentration metrics followed patterns similar to those of

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propellant sprays. Regardless of the nozzle type, the metrics did not differ significantly from the

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background concentration. The number of background nanoparticles was maintained at under 200

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particles/cm3, and the concentrations at each distance did not exceed the background level after

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spraying. The surface area and mass metrics were also similar to the background levels after spraying;

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therefore, the nozzle type did not affect the characteristics of airborne particles.

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(Table 3 here) Fig. 3 indicates the spatial-temporal distribution of particle concentrations after spraying by nozzle type based on SMPS data. The particle concentrations before spraying did not differ 14


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significantly among distances (p = 0.72), and the background level was therefore constant in the

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cleanroom. For nanoparticles from the propellant sprays, the concentrations were highest at the 1 m

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distance (GM: 5,565 particles/cm3, GSD: 1.6), followed by 2 m (GM: 4,186 particles/cm3, GSD: 2.0)

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and 3 m (GM: 1,466 particles/cm3, GSD: 2.6). Multiple comparisons indicated that the GMs of

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individual concentrations differed significantly among distances (p < 0.05). For larger particles 100 to

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420 nm in size, concentrations were highest at 2 m from the source (GM: 1,002 particles/cm3, GSD;

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1.7), followed by 1 m (GM: 899 particles/cm3, GSD; 1.5) and 3 m (GM: 782 particles/cm3, GSD; 1.7);

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however, the differences were not significant (p = 0.25). For pump sprays, the particle concentrations

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before and after spraying did not differ significantly with distance (p > 0.05).

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Figure 3. Comparison of particle number concentration before, during and after spraying by

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nozzle type. The ‘spraying’ indicates the duration of exposure time for initial 10 minutes during

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spraying and the ‘after’ indicates the duration of time remaining until the measurement was

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complete.

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Differences in particle concentrations by spray product characteristics As shown in Table 3, spatial-temporal particle dynamics varied depending on the nozzle type.

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Fig. 4 shows the difference in nanoparticle concentration at each distance by elapsed time.

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Nanoparticles sharply increased to the highest concentrations 1 min after spraying, and then steadily

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decreased to the background level at each distance. Table 4 indicates the significant differences

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among nanoparticle concentrations by elapsed time after spraying, with nanoparticle concentrations 15



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corrected based on the amount sprayed (g) for individual products. The elapsed time intervals were

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defined as 1, 3, 5, 10, 30, 60, 120, and 150 min after spraying. The background particle concentration

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was maintained at under 100 particles/cm3/g in the cleanroom. Sprayed nanoparticles also differed

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according to nozzle type, as previously discussed.

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Nanoparticles released from propellant sprays rapidly increased to their maximum

328

concentration 1 min after spraying at each distance: 602 (GSD; 2.1, 1 m), 403 (GSD; 2.0, 2 m), and

329

289 (GSD; 1.9, 3 m) particles/cm3/g, respectively. The concentrations showed a tendency to decrease

330

with distance from the spray source. In the near-field areas, the concentrations of nanoparticles at 1

331

min did not significantly differ from the concentrations at 5 min (p > 0.05), indicating a high potential

332

for exposure in the minutes immediately after spraying. The initial concentrations of nanoparticles in

333

the far-field areas followed patterns similar to those of the near-field areas, but the peak

334

concentrations persisted for a longer time after spraying: 10 min at 2 m from the source, and 30 min at

335

3 m (p > 0.05). Conversely, nanoparticle concentrations released from pump sprays did not

336

significantly differ before and after spraying; i.e., the level of background particles was constant

337

throughout the experiment at all sampling locations.

338

339

(Table 4 here)

Figure 4. Temporal variation in nanoparticles before and after spraying by nozzle type.

16


Page 16 of 38

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340


For propellant sprays, particle size distributions for the initial 5 min after spraying are shown in Fig.

341

5. The proportions of nanoparticles to the total particles measured (10-10,000 nm) were increased at

342

each distance, even though the total number of particles decreased with distance. In the initial 5 min

343

after spraying, the proportion of nanoparticles increased at each distance (1m, 82.9 to 85.8%; 2 m,

344

78.5 to 82.7%; 3 m, 81.4 to 83.6%), while those after pump type spraying were not significantly

345

different with the background level regardless of time and distance (not shown in Fig. 5).

17



346

Figure 5. Comparison of temporal size distributions by distance

347

for initial 5 min after spraying; (a) 1 m, (b) 2 m, (c) 3 m.

18


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348 349


Identification of target ENMs from filter samples Table 5 lists the ingredients identified based on analytical results from filter samples. The AgNP was

350

found in Product A and B by ICP-MS and SEM-EDX and it was matched with the advertised ENM on the

351

product label. In Product C, the AgNP was identified by only SEM-EDX and it was matched with the

352

ingredients on the label. The nanotechnology-based products (D, E, F) which did not specify a certain ENM

353

did not contain the ENM such as silver, silica, and titanium actually. Product G and H were also labelled to

354

contain the titanium dioxide and AgNP, respectively, and the declared ENMs were found in the filter samples

355

through both ICP-MS and SEM-EDX analysis. These products were also identified to contain other ENM

356

(e.g. Product G: Ag; Product H: titanium) as well as the declared ENM.

357 358

(Table 5 here) Fig. 6 shows FE-SEM images of the materials detected according to both spray nozzle type and

359

distance. The AgNP found in Product A was detected in single or aggregated form in both near- and far field

360

areas. The single particles were nano-sized, but the aggregated particles exceeded the nanoparticle range in the

361

near-field area (Fig. 6a, left). The AgNP released from Product A was also identified in aggregated form in

362

far-field areas, and the size of aggregates exceeded 100 nm (Fig. 6a, right). Product E was a coating spray

363

labeled as being “nanotechnology-based” without any specific ENMs being included in the labelling. Rod-

364

shaped single particles consisting of molybdenum (Mo), Ti, and Mg were detected in both near- and far-field

365

areas. Particles were found only in the single form, and were smaller than 100 nm (Fig. 6b). Product G, a

366

pump spray, was found to contain titanium dioxide. For Product G, larger droplets released in the form of

367

micrometer-sized particles were detected in near-field areas (Fig. 6c, left). This was a pattern dissimilar to

368

propellant sprays such as Products A and E, for which single or aggregated nanoparticles were identified in

369

the far-field areas. Titanium was identified as an ingredient of Product G. Due to their relatively large size,

370

particles released from Product G were not detected in far-field areas (Fig. 6c, right).

19



(a) Propellant type (Product A declared to contain AgNP, left; 1 m, right; 2 m)

(b) Propellant type (Product E, nanotechnology-based, left; 1 m, right; 2 m)

(c) Pump type (Product G declared to contain TiO2, left; 1 m, right; 2 m)

371 372 373

Figure 6. FE-SEM images of filter samples according to both nozzle type and distance.

Estimation of inhaled dose and deposited dose during the use of spray products Fig. 7 shows the inhaled doses, deposited doses and exposure factors according to nozzle type and

374

distance from the spray source. As particle size decreased, the number of inhaled particles increased. The

375

number of nanoparticles in the range of Dp0.011-0.1 was 1.2×108 ± 4.0×107 particles/kgbw/day. This was the

376

highest dose during propellant use, and was found in near-field areas (1 m). The next-highest dose was

377

9.1×107 ± 3.1×107 particles/kgbw/day, in far-field areas (2 m). The proportion of nanoparticles (Dp0.011-0.1)

378

among total particles (Dp0.011-10) was about 75.7% in near-field areas and 72.7% in far-field areas (Fig. 7a).

379

The deposited doses in each part of respiratory tract followed patterns similar to those of inhaled doses. Of the

380

nanoparticles inhaled during the use of propellant sprays, many were estimated to be deposited in the alveolar

381

region. In near-field areas, 4.6×107 ± 1.6×107 particles/kgbw/day were estimated to be deposited in the 20


Page 20 of 38

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382

alveolar region, while 3.6×107 ± 1.3×107 particles/kgbw/day were estimated to be deposited in this region in

383

far-field areas (Fig. 7b).

384

Conversely, inhalation exposure by mass followed an inverse pattern to that of particle number, i.e.,

385

particle exposure by mass increased with particle size. The dose by mass of particles in the Dp2.5-10 range was

386

19,390 ± 6,308 ng/kgbw/day, and was higher in far-field areas than 4,110 ± 1,460 ng/kgbw/day in near-field

387

areas during pump spray use. During the use of propellant sprays, the dose by mass for particles in the Dp2.5-10

388

range was estimated to be 17,740 ± 11,417 ng/kgbw/day in far-field areas, followed by 8,061 ± 4,138

389

ng/kgbw/day in near-field areas (Fig. 7c). These results can be explained by the presence of bigger

390

particulates generated by aggregation/agglomeration during the use of pump sprays, especially in far-field

391

areas. The particle mass deposited into respiratory tracts was highest in the nasal region due to the presence of

392

larger particles. The deposited doses for the nasal region during propellant use were 21,655 ± 14,280

393

ng/kgbw/day in far-field areas and 9,397 ± 3,985 ng/kgbw/day in near-field areas. During pump spray use, the

394

doses were 20,221 ± 6,685 ng/kgbw/day in far-field areas and 3,746 ± 1,335 ng/kgbw/day in near-field areas

395

(Fig. 7d). The exposure to nanoparticles by mass was only a small proportion of total exposure (less than 1%).

396

The dose by surface area of the inhaled and deposited particles was higher for particles larger than

397

100 nm in diameter. For propellant sprays, the inhaled dose by surface area for particles in the range of Dp0.1-

398

10

399

near-field areas, it was 1.1×107 ± 5.2×106 (pump sprays: 5.2 × 106 ± 1.1×106) µm2/kgbw/day (Fig. 7e). These

400

results can be attributed to the presence of larger particles in the far-field areas. The nasal region was the most

401

affected site based on surface area, accounting for 78.6% (1.3×107 ± 5.4×106 µm2/kgbw/day, far-field) and

402

73.5% (4.4×106 ± 1.8×106 µm2/kgbw/day, near-field) of the total exposure with propellant sprays, and 79.4%

403

(6.5×106 ± 9.6×105 µm2/kgbw/day, far-field) and 68.3% (1.1×106 ± 1.6×105 µm2/kgbw/day, near-field) of the

404

total exposure for pump sprays (Fig. 7f). More details on the inhalation exposure associated with individual

405

products, including descriptive statistics and figures, are provided in Table S1 of SI.

was highest in the far-field areas, at 2.4×107 ± 1.2×107 (pump sprays: 1.4×107 ± 4.6×106) µm2/kgbw/day. In

21



406

Figure 7. Comparison of inhaled dose and deposited dose according to both nozzle type and distance.

22


Page 22 of 38

Page 23 of 38

407 408


Discussion We evaluated the spatial-temporal dispersion of airborne nanoparticles through the use of

409

ENM-containing and nanotechnology-based spray products in a cleanroom. We also estimated the

410

associated ENM exposure by inhalation in the breathing zone and the deposited ENMs in each part of

411

respiratory tracts.

412

Previous studies assessing inhalation exposure and aerodynamic characteristics for ENM-

413

containing consumer products have been performed in small chambers or realistic rooms.10, 12-15, 19, 24-25,

414

which are conditions under which it is difficult to control the level of background particles. High

415

levels of background particles induces larger particles in the form of agglomerates/aggregates,

416

because the former act as seeds for coagulation. This reduces the exposure to nanoparticles by both

417

reducing nanoparticle concentration and by shifting the particle size distribution beyond the

418

nanoscale.12 The cleanroom used in the present study was more suitable for assessing particle

419

behavior because the indoor air conditions, including background particulates and

420

temperature/humidity, could be controlled using a ventilation system. Furthermore, surface deposition

421

due to gravitational settling, Brownian motion, and turbulent diffusion plays a role as a particle sink

422

during transport from the source to the receptor, while the resuspension of deposited particles will

423

result in secondary emission sources.2 We therefore restricted access to the cleanroom by persons

424

other than the sprayer, minimizing the resuspension of settled particles by human activity. The

425

conditions in the present study therefore represented the optimal environment for nanoparticle

426

sampling.

427

To evaluate the airborne nanoparticles, we conducted simultaneous real-time monitoring and

428

filter sampling. The offline samples collected using MCE filters and copper grids complemented the

429

lack of real-time monitoring data, because the DRIs cannot determine particle type or chemical

430

composition. In particular, because the ENM-containing sprays contained solutions comprising

431

organic solvents and compressed gases, it is important to remove the influence of droplets of

432

aerosolized solutions during air monitoring. It has been reported that aerosol droplets containing

433

volatile components can be removed during aerosol measurement using a thermodesorber consisting 23



434

of a heating section and an adsorption section containing activated carbon.26-28 In a previous study, a

435

low-flow thermodesorber unit was also used to dry wet aerosols containing ENMs generated by

436

consumer sprays. The thermodesorber decreased the number of particles by more than 80%, and the

437

authors determined that nano-sized aqueous droplets likely caused an instrument signal during

438

spraying.10 The thermodesorber used in the present study also provided an 81.5% decrease in particles.

439

Although particles may be lost through sedimentation and diffusion, these processes can be negligible

440

in the measurement of nano-scale aerosols.27 Our results showed that the use of a thermodesorber

441

assisted in the analysis of aerosols containing organic compounds.

442

The behavior of nanoparticles released from sprays is influenced by several processes, including: 1)

443

the release and vaporization of solvent, 2) the sedimentation of large (micrometer range) particles and

444

new particle formation through aggregation with other small particles, and 3) the dispersion of

445

nanoparticles over time in the air in the form of single or aggregated particles.5 As shown in Fig. 4,

446

the nanoparticles released from propellant sprays increased to the highest concentrations for initial 1

447

min after spraying, and decreased to the background level after about 2 hours. Because there was no

448

ventilation in the clean room, it might take longer time of dispersion in the air. Conversely, there was

449

no significant difference between before and after spraying for pump sprays due to little increase of

450

nanoparticles after pump type use and rapid dropping of the larger particles.10 It is known that a

451

number of small particles are released into the air by propellant sprays, but not by pump sprays. This

452

difference is attributed primarily to nozzle type, even though the released particles vary among

453

products according to several variables (e.g., spraying duration and frequency, sprayed amount,

454

measuring period). Therefore, it can be concluded the difference of nozzle type might influence the

455

particle behaviors and its dispersion time in the air. Furthermore, it will be also directly connected to

456

consumers’ inhalation exposure.

457

Due to the complexity of various factors, it is difficult to compare the results among studies.

458

Losert et al.5 identified several general findings through a review of the literature. For example, all

459

studies reported nanoparticle release only when propellant sprays were used. Studies that analyzed

460

pump sprays concluded that agglomerated particles, but no single particles, were released; 24


Page 24 of 38

Page 25 of 38


461

furthermore, the number of particles released was much lower than that of propellant sprays.5, 12

462

Although there are numerical differences among studies in the number of particles released, these

463

findings were broadly consistent with the results of the present study. Approximately 600 times more

464

nanoparticles were released during the use of propellant sprays than during the use of pump sprays,

465

the latter of which did not differ significantly from the level of background particles (< 200

466

particles/cm3).

467

Several recent studies have assessed exposure based on particle number rather than mass.10, 12-

468

13, 15, 19, 24, 29-30

469

space, but also time.11, 19 Exposure to a large number of nanoparticles may occur primarily in the first

470

few minutes after spraying, close to the spray source.10, 19 This observation is consistent with the

471

results of the present study (Fig. 4 and 5). Our results show that particle concentration was a more

472

appropriate metric for nanoparticle exposure than surface area or mass. We found that particles

473

dispersed farther from the spray source had higher surface area than particles closer to the spray

474

source. Bekker et al.19 also provided exposure data on surface area for released particles, but surface

475

area was higher in far-field area. The authors focused on the number concentration and did not

476

mention why the surface area was higher in the farther distance.19 Small particles usually have large

477

surface area, but we also could not find it obviously. We may guess the causes as follow; The surface

478

area instrument used in our study cannot differentiate the particle size and can only measure the

479

surface area concentrations for all particles in the range from 10 to 10,000 nm. In addition, SMPS and

480

OPS used in our study can measure the particle number by size channel (SMPS and OPS: 10-13.3 nm,

481

13.3-17.8 nm ··· 8-10 µm), thereby the difference of individual particle size in each size channel may

482

lead to the gaps of surface area between exposure compartments because the surface area is relative to

483

the square of diameter.

484

. In assessing inhalation exposure, it is also important to assess particles over not only

The persistence of airborne nanoparticles in the area where products are used is a crucial

485

factor for assessing exposure. It can influence the risk of exposure not only for product users, but also

486

for bystanders in the area. This study allowed the conceptual model by Schneider et al.31 for

487

separation of exposure compartment. The authors have provided the concept of transmission 25



488

compartments consisted of near-field and far filed compartment by 1 m distance from a source. It can

489

be defined the near-field as a volume of air within 1 m in any direction of human head, and the far-

490

field comprises the remainder of the room. If the products used for body like as cosmetic sprays or

491

spraying onto surface, the exposure at human breathing zone might be more suitable by personal

492

sampling. The DRIs used for aerosol monitoring in this study had a limitation to personal sampling

493

due to the bulky size, and there was no choice but to conduct area monitoring in the exposure

494

compartments by 1 m distance.

495

Peak exposure occurs in the first few minutes after spraying in areas near the spray source,

496

but we also found that particle concentrations reached a steady-state level above the background

497

concentration throughout the duration of the measurement period. As indicated in Table 4, particle

498

concentrations peaked in near-field areas one minute after spraying propellant products, and

499

concentrations persisted for at least 10 minutes; thus, peak exposure could be possible for a period of

500

time after spraying. As shown in Fig. 5, the number of particles ~100 nanometers in diameter

501

increased for 1 min after spraying at 1 and 2 m from the spray source (bimodal distribution). This

502

could be explained by the evaporation of volatile compounds surrounding aerosols.32 The authors

503

have shown that volatile compounds in aerosols that have an initial diameter of ~100 µm evaporate

504

within four seconds. We speculate that the solvent surrounding particles might evaporate, and the

505

coagulation of smaller particles then proceeds rapidly, immediately after spraying.

506

It is important to identify the presence of target ENMs using filter samples, because it is

507

difficult to distinguish between aerosols and ENMs using DRIs. The ENMs advertised on the product

508

labels were confirmed by the results of both SEM-EDX and ICP-MS analysis for only three products

509

(A, B, G). This finding may have resulted from analytical limitations, or from errors in product

510

labelling. Because the products contained only a small quantity of ENMs, we may have collected an

511

insufficient amount of material; or products may have contained no ENMs at all. According to a

512

review of nanomaterial consumer products, about half of all products do not provide a detailed

513

composition.3 Indeed, many products make advertising claims based on nanotechnology without

514

effectively using nanotechnology-enhanced materials.16 The lack of transparency concerning the 26


Page 26 of 38

Page 27 of 38


515

presence of ENMs in products makes it difficult for stakeholders (consumers, researchers, and

516

regulators) to assess the risks associated with product use.33

517

Inhalation exposure can be estimated through either modeling or actual personal monitoring.

518

To estimate exposure more accurately, it is advisable to conduct a full range of measurements for each

519

ENM-containing spray; however, such an endeavor would be very time-consuming and costly.

520

Although modeling is a very cost-effective method, it also has the drawback that minor variations

521

among assumptions can lead to highly disparate outcomes.5 In the present study, we estimated

522

inhalation exposure using mathematical modeling and experimental data. We found that spray nozzle

523

type was one of the main factors influencing the level of inhalation exposure. As in previous studies,

524

we found that it had an effect on not only spatial-temporal size distribution, but also on the fate of

525

nanoparticles after spraying.12, 14, 19

526

The present study had some limitations. First, a cleanroom has the advantage of being convenient for

527

controlling the level of background particles, but is also an imperfect representation of real-life

528

conditions. We were unable to take into account the transportation of particles by natural air flow,

529

because we focused on the dynamics of particle dispersion in the air. Second, all particles sampled by

530

real-time monitors were assumed to have the density of the target ingredients for ENM-containing

531

products, and those of nanotechnology-based products were assumed to have the density of air.

532

Therefore, inhalation exposure may have been over- or underestimated due to the particle density

533

assumed in the model. Finally, though the use of thermodesorber had an advantage to measure the

534

nanoparticles accurately, it might not represent the realistic situations for behaviors of particles and

535

human inhalation. By removing the water and organic solvents artificially, it can also cause

536

agglomeration, aggregation or shrinking particles, thereby may influence not only the morphology but

537

the size distribution and surface area.34 In this study, measurement was done at 1 m, 2 m and 3 m that

538

seemed to be far distance for natural drying process occurring before the measurement. However, still

539

uncertainty remains and further investigations on the elaborate measurement and interpretation are

540

necessary.

27



541

All propellant spray products selected for this study released nanoparticles, regardless of

542

whether ENMs were declared on the labels, because the real-time monitors could not distinguish

543

between ENMs and other small particles. Based on an offline analysis using ICP-MS and SEM EDX,

544

we found that only three products contained the ENMs listed on the labels. Because of the

545

discrepancy between the declared and actual ingredients, it is critical that accurate nano-labeling be

546

legislated in order to permit more accurate assessments of the risks of human exposure.

547

In conclusion, we found that the spray nozzle type was a crucial factor determining

548

inhalation exposure. Propellant sprays released a larger quantity of nanoparticles which dispersed over

549

a greater distance and persisted for a longer time in the air due to their small size. Conversely, pump

550

sprays produced larger aerosol droplets that settled to the ground close to the source. Estimates of

551

inhalation exposure based on inhaled and deposited doses also supported the notion that nanoparticles

552

were more abundant during the use of propellant sprays. We can therefore conclude that propellant

553

sprays cause a higher risk of exposure than pump sprays. As public concerns on the hazards of

554

consumer products increase, information on the potential exposure to ENMs through the use of

555

nanomaterial-containing products will be useful for estimating exposure risk and developing

556

regulatory policies to protect public health.

557

Supporting Information

558

The results of thermodesorber test aforementioned in Methods and materials are available in Figure

559

S1 and S2. The information on the equations for estimating the inhalation exposure and the summary

560

of inhalation exposure on individual products are also shown in SI-Eq, Table S1 and Figure S3-S4,

561

respectively.

562

Acknowledgements

563

This work was supported by the National Institute of Environmental Research (No. NIER-SP2015-

564

254) and BK21 Plus project (No. 5280-20160100) of Grant funded by the Korean Government.

565

Declaration of interests

566

The authors declare they have no actual or potential competing financial interests.

28


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567

The English in this document has been checked by at least two professional editors, both native

568

speakers of English. For a certificate, please see:

569

http://www.textcheck.com/certificate/b8usbk

570

29



571

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(23)

643 644

KMOE Public Notification No. 2014-50. of the National Institute of Environmental Research. Korean Ministry of Environment. 2014.

(24)

Kim, E.; Lee, J.H.; Kim, J.K.; Lee, G.H.; Ahn, K.; Park, J.D.; Yu, I.J. Case study on risk

645

evaluation of silver nanoparticle exposure from antibacterial sprays containing silver

646

nanoparticles. J. Nanomater. 2015, 2015:1-8. http://dx.doi.org/10.1155/2015/346586.

647

(25)

648 649

Rowley, J.; Crump, D. Measurements of the dispersal of aerosol sprays in a room and comparison to a simple decay model. J. Environ. Monitor. 2005, 7 (10), 960-963.

(26)

An, W.J.; Pathak, R.K.; Lee, B.-H.; Pandis, S.N. Aerosol volatility measurement using

650

an improved thermodenuder: Application to secondary organic aerosol. J. Aerosol. Sci.

651

2007, 38 (3), 305-314.

652

(27)

Burtscher, H.; Baltensperger, U.; Bukowiecki, N.; Cohn, P.; Hüglin, C.; Mohr, M.;

653

Matter, U.; Nyeki, S.; Schmatloch, V.; Streit, N. Separation of volatile and non-volatile

654

aerosol fractions by thermodesorption: instrumental development and applications. J.

655

Aerosol. Sci. 2001, 32 (4), 427-442. 32


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656

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657 658

Fierz, M.; Vernooij, M.G.; Burtscher, H. An improved low-flow thermodenuder. J. Aerosol. Sci. 2007, 38 (11), 1163-1168.

(29)

Nørgaard, A.W.; Jensen, K.A.; Janfelt, C.; Lauritsen, F.R.; Clausen, P.A.; Wolkoff, P.

659

Release of VOCs and particles during use of nanofilm spray products. Environ. Sci.

660

Technol. 2009, 43 (20), 7824-7830.

661

(30)

Shimada, M.; Wang, W.-N.; Okuyama, K.; Myojo, T.; Oyabu, T.; Morimoto, Y.; Tanaka,

662

I.; Endoh, S.; Uchida, K.; Ehara, K. Development and evaluation of an aerosol

663

generation and supplying system for inhalation experiments of manufactured

664

nanoparticles. Environ. Sci. Technol. 2009, 43 (14), 5529-5534.

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Schneider, T.; Brouwer, D.H.; Koponen, I.K.; Jensen, K.A.; Fransman, W.; Van Duuren-

666

Stuurman, B.; Van Tongeren, M.; Tielemans, E. Conceptual model for assessment of

667

inhalation exposure to manufactured nanoparticles. J. Expo. Sci. Env. Epid. 2011, 21

668

(5), 450-463.

669

(32)

The ConsExpo spray model-Modelling and experimental validation of the inhalation

670

exposure of consumers to aerosols from spray cans and trigger sprays: RIVM Report

671

320104005; National Institute for Public Health and the Environment: Bilthoven, the

672

Netherlands, 2009.

673

(33)

674 675 676

Throne-Holst, H.; Rip, A. Complexities of labelling of nanoproducts on the consumer markets. Eur. J. Law. Technol. 2011, 2 (3).

(34)

Burtscher, H. Physical characterization of particulate emissions from diesel engines: a review. J. Aerosol. Sci. 2005, 36 (7), 896-932.

677

33


678

679


Page 34 of 38

Table 1. General details of the selected consumer spray products in this study. Nozzle type

Propellant type

Pump type

a

Product

Intended use

Declared ENMs a

Product volume (mL)

Nozzle size (mm)

280

1

330

1

330

0.5

500

0.5

-

210

0.5

-

Polydimethylsiloxane (-)

250

0.5

150

< 0.5

1,000

0.5

Ingredients (proportion) listed on MSDS/label Ethyl alcohol (40-50%), Water (2030%), Propane (10-20%), Butane (1020%), Boric acid with 1-amino-2propanol (1-5%), Chamaecyparis obtusa (0.5-1.5%), lauryldimethylbetaine (0.5-1.5%), Dodecane, 1-chloro- (0.1-1.0%), Diethylenetriamine (0.1-1.0%) Ethyle alcohol (40-50%), perfume (110%), AgNP (1-10%), propane (1020%), N-bunane (30-40%) Ethanol (50-60%), green tea extract (1-5%), propane (10-20%), butane (20-30%) Propan-2-ol (30-60%), n-butyl acetate (1-10%), polymer fluor (1-10%), propane (10-20%), butane (5-10%) Mixture (25-50%) of hydrocarbons C7-C9, n-alkanes, isoalkanes, cyclics, 2, 6-Di-t-butyl-4-methyl-phenol (0.25-1%)

A

Cleaner household device

AgNP

B

Deodorizer for air conditioner

AgNP

C

Deodorizer for air conditioner

AgNP

D

Coating for functional clothing

Nanotechnologybased

E

Coating for functional clothing

Nanotechnologybased

F

Cleaner for surface

Nanotechnologybased

G

Air deodorizer

TiO2

Water (97%), TiO2 (< 3%)

H

Air freshener

AgNP

Ethyl alcohol (20-25%), AgNP (-), 1Methoxoxy-2-propanol (5-10%)

Ingredients on the product label: AgNP, silver nanoparticles, TiO2, titanium dioxide.

34


Note

- Advertised containing AgNP in online market - Not described AgNP in MSDS

- Advertised containing AgNP on the label - Not described AgNP in MSDS

Not described for target ENM in MSDS MSDS not available -

Page 35 of 38

680


Table 2. Factors used for calculation of inhalation exposure.

Product

681 682 683 684

Sprayed amount (g) a

Fraction of nanoparticles b

Common exposure factor related to users d, 23

Exposure factors related to use characteristics 23 Using location

Exposure time (min) c

Use amount (g/day)

A

16.7

0.89

- home (living room) - car indoor

143.8

5.55

B

22.2

0.85

- car indoor

44.8

5.55

C

14.5

0.75

- car indoor

44.8

5.55

D

9.8

0.66

- home (balcony)

4.4

11.47

E

7.7

0.78

- home (balcony)

4.4

11.47

F

2.2

0.68

- car indoor

44.8

5.61

G

2.9

0.44

- home (bed room)

138.3

7.56

H

8.3

0.46

- home (living room)

138.3

5.55

a

Body weight (kg)

Inhalation rate (L/min)

64.2

9.9

Average sprayed amounts under spray experiments in the clean room. Proportions of nanoparticles from merging data with SMPS and OPS (10-10,000 nm). c Average staying time at the place. d Fixed factors for calculating inhalation exposure (average body weight and inhalation rate of all adults). b

35


685

686


Page 36 of 38

Table 3. Summary of particle concentrations by each metric before, during and after spraying. Particle concentrations a 3

Surface area (µm2/cm3)

Number (particles/cm ) Product

1m < 100 nm

A

B

C

D

E

F

G

H

a

Mass (µg/m3)

Period

Range

2m 100-400 nm

Range

< 100 nm

Range

3m 100-400 nm

Range

< 100 nm

Range

1m 100-400 nm

Range

10-10,000 nm

2m Range

10-10,000 nm

1m Range

< 1,000 nm

Range

Before

81.7 (1.6)

20-152

32.6 (1.8)

5-78

85.1 (1.7)

10-143

32.6 (1.9)

5-76

81.7(1.9)

8-140

28.9(2.0)

2-62

0.7(1.2)

0.5-1.0

1.1(1.3)

0.4-1.6

0.5(1.2)

0.5-3.3

Spraying

11,227.0 (1.2)

9,132-17,008

544.2 (1.5)

370-1,534

9,453.8(1.2)

6,845-14,731

425.8 (1.4)

185-693

9,347.4(1.1)

8,054-12,872

548.0(1.3)

328-909

16.7(1.2)

10.7-26.0

34.1(1.3)

24.1-61.5

61.1(1.5)

51.1-150.3

After

1,548.5 (2.9)

368-11,547

204.8 (1.6)

94-461

1,536.4(2.9)

392-11,169

160.3 (1.7)

71-511

1,339.4(2.6)

394-7,803

119.0(1.7)

45-535

0.7(8.2)

0.1-17.9

6.4(2.1)

2.5-29.9

6.8(3.1)

1.6-58.3

Before

110.4 (1.4)

43-173

113.8 (1.4)

54-589

80.3 (1.5)

29-148

124.8 (1.5)

51-242

77.8(1.6)

15-141

96.8(1.3)

53-157

0.1(1.3)

0.1-0.2

1.5(1.3)

0.9-2.3

1.8(1.1)

1.4-2.4

Spraying

7,468.9 (1.2)

5,387-11,953

812.7 (1.3)

688-1,522

7,457.1(1.1)

6,108-8,060

1,084.9(1.2)

881-1,591

6457.9(1.1)

5,019-7,383

832.6(1.1)

688-1,001

12.0(1.1)

10.6-13.9

24.5(1.1)

21.9-33.8

72.5(1.1)

65.7-94.5

After

2,538.7(2.0)

757-7,984

362.1 (1.6)

203-1,188

2,500.5(2.0)

737-7,983

96.8 (1.3)

183-1,926

2157.6(1.9)

700-6,520

342.7(1.7)

163-866

0.6(8.2)

0.1-12.0

9.5(1.6)

4.7-23.5

25.2(1.7)

11.7-69.2

Before

101.0 (1.1)

77-126

137.0 (1.1)

95-172

76.4 (1.2)

52-99

127.6 (1.2)

83-181

47.5(1.3)

24-119

125.0(1.2)

91-420

0.8(1.5)

0.1-1.1

1.4(1.1)

1.1-1.9

2.8(1.2)

2.3-4.3

Spraying

5,168.4 (1.3)

4,256-10,209

1,032.8(1.1)

889-1,366

4,374.6(1.2)

3,623-7,121

1194.6 (1.1)

1,014-1,528

4256.4(1.3)

3,349-9,185

1121.9(1.1)

955-1,579

12.7(1.3)

10.4-25.8

30.9(1.2)

26.2-38.6

146.2(1.2)

107.7-181.9 11.1-121.5

After

861.3 (2.2)

276-4,255

395.4 (1.5)

207-945

655.5 (2.2)

205-3,419

375.1 (1.5)

205-1,068

589.8(2.3)

178-3,323

381.6(1.5)

207-936

0.5(7.4)

0.1-10.0

6.9(1.8)

3.1-25.1

31.3(2.0)

Before

125.0 (1.1)

102-150

70.8 (1.1)

50-92

208.2 (1.1)

168-253

84.3 (1.2)

50-109

73.9(1.1)

55-93

76.0(1.1)

58-100

0.1(1.1)

0.0-0.1

0.6(1.2)

0.5-1.1

1.3(1.1)

1.2-1.5

Spraying

3,160.0 (1.4)

2,554-7,146

1,257.4(1.6)

901-4,181

1,391.9(1.4)

1,061-3,362

1,609.1(1.8)

853-7,443

1863.5(1.1)

1,663-2,306

1097.7(1.1)

972-1,263

6.5(1.4)

5.2-13.8

20.9(1.3)

16.1-40.3

112.1(1.3)

89.6-192.6 3.2-88.5

After

790.7 (2.0)

268-2,607

289.6 (1.7)

142-918

622.1 (1.8)

270-1,816

488.6 (1.7)

198-1,520

520.6(2.1)

180-1,694

306.5(1.6)

162-948

0.1(4.2)

0.1-4.9

5.3(2.0)

1.4-18.2

18.6(2.4)

Before

126.7 (1.1)

101-144

145.7 (1.1)

107-189

100.2 (1.2)

61-128

137.6 (1.1)

101-195

51.2(1.3)

32-120

136.9(1.1)

108-183

0.1(1.0)

0.0-0.1

1.6(1.1)

1.2-1.9

2.9(1.2)

2.5-4.2

Spraying

3,897.4 (1.1)

3,250-4,820

1,060.8(1.1)

854-1,379

2,994.7(1.1)

2,518-3,764

1,072.8(1.2)

888-1,591

1674.7(1.3)

858-1,917

1072.8(1.2)

630-995

13.3(1.5)

9.9-35.8

26.6(1.1)

23.1-32.8

162.4(1.5)

118.4-427.7 7.0-112.2

After

657.6 (2.0)

266-3,172

421.3 (1.4)

250-921

510.1 (2.1)

182-2,417

421.1 (1.4)

225-891

364.4(2.0)

147-1,636

386.1(1.5)

236-925

0.1(5.4)

0.1-9.7

6.6(1.7)

3.3-22.4

0.1(2.3)

Before

29.8 (2.3)

1-73

13.5 (2.3)

1-43

34.2 (2.4)

1-76

15.6 (2.2)

1-47

26.6(3.2)

1-69

19.4(3.3)

0-40

0.5(1.6)

0.4-4.3

0.7(1.2)

0.5-1.0

0.5(1.0)

0.4-0.5

Spraying

64.9 (1.1)

56-74

28.5 (1.5)

15-43

75..9 (1.1)

67-90

34.0 (1.2)

26-48

66.0(1.1)

58-75

29.8(1.2)

24-42

0.3(1.2)

0.2-0.4

1.1(1.1)

0.9-1.1

0.6(1.1)

0.5-0.6

After

86.2 (1.1)

63-115

47.4 (1.3)

15-79

95.4 (1.1)

68-118

50.6 (1.2)

25-84

90.9(1.1)

68-118

41.0(1.2)

17-68

0.1(2.8)

0.0-0.2

1.2(1.1)

0.9-1.4

0.5(1.1)

0.5-0.6

Before

127.6 (1.1)

109-146

112.8 (1.1)

83-147

92.1 (1.1)

73-106

103.8 (1.1)

77-133

61.7(1.2)

32-99

109.8(1.1)

90-148

0.5(1.5)

0.2-1.3

1.3(1.1)

1.1-1.5

2.5(1.1)

2.2-3.0

Spraying

132.5 (1.1)

123-136

125.4 (1.1)

116-138

102.1 (1.1)

98-111

115.0 (1.1)

104-132

76.4(1.1)

67-96

124.4(1.1)

108-151

0.2(1.3)

0.1-0.3

1.6(1.1)

1.5-1.8

5.8(1.2)

3.2-7.4

After

126.7 (1.1)

105-149

126.2 (1.1)

103-153

95.9 (1.1)

82-117

122.4 (1.1)

98-144

73.6(1.2)

55-163

125.5(1.1)

102-198

0.1(1.4)

0.0-0.2

1.5(1.1)

1.3-1.8

4.9(1.1)

4.5-6.0

Before

123.8 (1.1)

95-147

118.7 (1.1)

94-145

93.8 (1.2)

61-121

106.2 (1.2)

71-135

61.2(1.3)

30-89

109.2(1.1)

88-133

1.2(1.2)

0.9-1.6

0.7(1.2)

0.5-0.9

2.5(1.0)

2.3-2.5

Spraying

165.8 (1.1)

152-214

156.7 (1.1)

140-180

135.8 (1.3)

117-274

153.5 (1.2)

128-255

92.7(1.1)

85-100

136.0(1.1)

127-154

0.9(1.1)

0.9-1.0

1.4(1.9)

1.0-9.5

3.8(1.8)

2.9-19

After

164.0 (1.1)

143-241

165.1 (1.1)

122-231

135.5 (1.1)

228-164

154.3 (1.1)

120-193

114.6(1.2)

87-245

149.8(1.1)

124-185

0.7(1.2)

0.5-1.2

1.3(1.1)

1.1-1.5

2.9(1.1)

2.5-5.0

The representative values for particle concentrations were indicated to geometric mean (geometric standard deviation) and range.

36


Page 37 of 38

687

688 689 690


Table 4. Comparison of particle concentrations by elapsed time after spraying at each distance. Number concentration per sprayed amount (particles/cm3/g) Distance a

Numbering

a1

1m

2m

3m

Elapsed time b (min) Before spraying

Propellant type < 100 nm F Mean ± SD c GM(GSD) d 9.7±6.8 7.9 (1.9)

Pump type

a2-a9

< 100 nm Mean ± SD GM(GSD) 29.0±24.0 22.1 (2.2)

Significance**

R2

a2

1

731.7±422.0

602.0 (2.1)

a6-a9

33.3±21.8

28.4 (1.8)

a3 a4 a5 a6 a7 a8 a9 b1 b2 b3 b4 b5 b6 b7 b8 b9 c1

3 5 10 30 60 120 150 Before spraying 1 3 5 10 30 60 120 150 Before spraying

460.1±192.0 371.8±179.1 403.7±230.8 257.3±184.3 120.2±81.4 38.1±25.2 27.5±15.5 11.0±12.3 486.8±277.0 373.3±254.7 322.8±141.5 344.3±214.4 228.3±192.7 107.3±90.3 33.8±27.7 25.6±16.3 5.9±2.9

414.5 (1.7) 322.5 (1.8) 357.1 (1.6) 215.8 (1.7) 102.6 (1.7) 31.4 (1.9) 23.8 (1.7) 7.6 (2.2) 403.2 (2.0) 288.9 (2.2) 292.2 (1.6) 293.9 (1.8) 178.1 (1.9) 85.4 (1.9) 26.2 (2.1) 21.0 (1.9) 5.2 (1.7)

a6-a9 a6-a9 a2, a7-a9 a2, a7-a9 a2, a7-a9 a2-a7 a2-a7 b2-b9 b6-b9 b7-b9 b7-b9 b7-b9 b2, b7-b9 b2-b5, b8-b9 b2-b7 b2-b7 c2-c9

32.2±23.0 32.7±22.2 34.9±18.0 35.3±19.1 34.3±18.2 33.5±17.1 35.0±20.7 22.0±15.2 25.9±13.3 26.2±14.3 26.9±15.0 26.5±13.5 26.7±12.1 26.4±10.8 26.9±14.4 26.9±15.4 15.2±8.5

27.0 (1.8) 27.5 (1.8) 32.0 (1.7) 31.2 (1.7) 30.3 (1.7) 29.9 (1.7) 30.0 (1.8) 18.5 (1.9) 23.3 (1.6) 23.2 (1.7) 23.7 (1.7) 23.8 (1.6) 24.3 (1.6) 24.6 (1.5) 23.9 (1.7) 23.0 (1.9) 13.3 (1.7)

97.03*

64.41*

0.86

0.80

c2

1

367.5±328.4

288.9 (1.9)

c7-c9

19.3±10.5

16.2 (2.0)

c3

3

351.5±219.3

298.8 (1.8)

c7-c9

19.0±10.1

16.4 (1.8)

c4

5

296.4±166.3

264.5 (1.6)

c7-c9

18.9±10.3

16.3 (1.8)

c5

10

289.3±161.7

256.2 (1.6)

20.2±9.9

17.7 (1.8)

c6

30

179.0±119.8

151.1 (1.8)

c8-c9

18.7±12.1

15.1 (2.1)

82.14*

c7-c9

0.84

c7

60

90.2±72.0

71.8 (2.0)

c2-c6, c8-c9

20.6±11.1

18.0 (1.8)

c8

120

29.1±26.4

20.6 (2.4)

c2-c7

21.1±13.0

17.8 (1.9)

c9

150

20.7±15.8

15.6 (2.3)

c2-c7

20.5±13.4

16.9 (2.0)

a

Distance from a sprayer, b Elapsed time after spraying, c Standard deviation, d Geometric mean (geometric standard deviation).

*

Significant model at p < 0.0001, ** Significant comparison at the 0.05 of p-value through multiple group comparison test (post hoc Tukey test), *** No significant model (p > 0.05).

37


F

Significance

R2

0.25***

-

0.04

0.19***

-

0.03

0.16***

-

0.02


691

Page 38 of 38

Table 5. Comparison of declared ENMs and analyzed ingredients based on air samples.

Type

Propellant

Pump

Product

Declared ENMs

Identified ingredients (ICP-MS)

Matched ingredients

Chemical compositions (FE-SEM-EDX)

Declared ENMs vs. ICP/MS

Declared ENMs vs. EDX

ICP/MS vs. EDX

A

AgNP

Ag, Cr, Pb, Cd, Mg

Ag

Ag

Ag

Ag

B

AgNP

Ag, Cr, Fe, Mn, Pb, Cd, Mg

Ag

Ag

Ag

Ag

C

AgNP

Cr, Cu, Zn, Pb, Cd, Ti, Mg

Ag

-

Ag

-

D

Nanotechnologybased

Cr, Mn, Fe, Ni. Cu, Al, Cd, Ti, Mg

F

-

-

-

E

Nanotechnologybased

Cr, Mn, Cu, Ni, Cu, Cd, Mg

Mo, Mg, Ti

-

-

Mg

F

Nanotechnologybased

Cu, Fe, Ni, Pb, Cd, Mg

Cu, Zn, Si

-

-

-

G

TiO2

Ag, Ti, Pb, Cd, Mg

Ag, Ti

Ti

Ti

Ag, Ti

H

AgNP

Ag, Cr, Ni, Cu, Fe, Pb, Cd, Ti, Mg

Ti, Na

Ag

-

Ti

692

38


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