ARTICLE pubs.acs.org/est
Vacuum Cleaner Emissions as a Source of Indoor Exposure to Airborne Particles and Bacteria Luke D. Knibbs,†,‡ Congrong He,†,‡ Caroline Duchaine,†,§ and Lidia Morawska*,†,‡ †
International Laboratory for Air Quality and Health and ‡Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Australia § Departement de Biochimie, de Microbiologie et de Bioinformatique, Universite Laval, Quebec, Canada
bS Supporting Information ABSTRACT: Vacuuming can be a source of indoor exposure to biological and nonbiological aerosols, although there are few data that describe the magnitude of emissions from the vacuum cleaner itself. We therefore sought to quantify emission rates of particles and bacteria from a large group of vacuum cleaners and investigate their potential determinants, including temperature, dust bags, exhaust filters, price, and age. Emissions of particles between 0.009 and 20 μm and bacteria were measured from 21 vacuums. Ultrafine ( 0.54 μm)
price
age
1 1 0.42
1
Numbers in bold indicate statistical significance at the 5% level (two-tailed).
range were characterized by a mean CMD of 14 nm, while emissions in the UVAPS range exhibited a continuation of the accumulation mode tail and no distinct peaks. By contrast, vacuum 10 emitted particles in the SMPS range with a mean CMD of 146 nm, and UVAPS measurements revealed two small peaks at approximately 2.2 and 5.5 μm. Vacuums 1 and 10 are used as examples here as they represent two markedly different emission spectra. Emission spectra from the majority of vacuums we tested were more comparable to those of vacuum 1 rather than vacuum 10. 3.1.4. PM2.5. Mean emissions of PM2.5 from cold vacuums ranged from 4.1 101 to 2.0 103 μg min1 (Table 1). Emissions from warm vacuums spanned 2.4 101 to 2.9 103 μg min1 (Table 2). After removal of the dust chamber or bag, emissions were between 4.3 101 and 5.4 103 μg min1. When the
exhaust filter was removed, emissions from the test group ranged from 4.1 101 to 7.2 102 μg min1. 3.1.5. Bacteria. Table 3 presents bag dust bacteria content and emission rates from cold and warm vacuums. Mean bacteria emissions from cold vacuums ranged from 0 to 6.4 105 bacteria min1. Warm start emissions were between 3.0 103 and 7.4 105 bacteria min1. The bacteria content of dust in the chamber or bag ranged from 0.03 to 15.9 106 bacteria g1 dust. No statistically significant correlation was observed between bag dust bacteria content and either cold or warm start bacteria emissions (Table 2, Supporting Information). 3.1.6. Correlation between Emission Rates. Table 4 shows Spearman’s rank correlation coefficients between mean ERs measured during cold starts. Statistically significant correlations were observed between UFPs, 0.5420 μm particles, and PM2.5. 538
dx.doi.org/10.1021/es202946w |Environ. Sci. Technol. 2012, 46, 534–542
Environmental Science & Technology
ARTICLE
Table 5. Comparison with Results of Previous Vacuum ER Studies study this study
vacuum
parameter
ER (particles 109 min1) ER (particles 106 min1) ER (μg min1) value
Electrolux Z570 (14 V) number of UFPs
0.004
min
Piranha PetPal
number of UFPs
108a
max
Afshari et al.16
unknown
number of UFPs
38
Gehin et al.18
unknown
number of UFPs
1092
He et al.15
unknown
number of UFPs
97
Lioy et al.12
Hoover 53611
number of UFPs
82
Szymczak et al.17
Thomas Junior 1516
number of UFPs
0.04
min
number of UFPs number of UFPs
130 60
max
Wallace and Ott20 unknown this study
Dyson DC08
number of 0.5420 μm particles
0.04
min
Ryobi VC20HD
number of 0.5420 μm particles
1215a
max
Afshari et al.16
unknown
number of >0.3 μm particles
30
Lioy et al.12
Miele S4321
number of 0.33.0 μm particles
0.10
min
Panasonic MC-V9620
number of 0.33.0 μm particles
334
max
Thomas Junior 1518
number of 0.32.0 μm particles
25
Willeke et al.14
unknown
number of 2.020 μm particles number of 0.34.0 μm particles
0.01 70
this study
Dyson DC08
mass of
