Environ. Sci. Techno/. 1989, 23, 610-614
Characterization of Environmental Tobacco Smoke Goran Lofroth,t Robert M. Burton,* Linda Forehand,§ S. Katharine Hammond,Il Robert L. Seila,' Roy B. Zweidinger,* and Joellen Lewtas',' Health Effects Research Laboratory and Atmospheric Research and Exposure Assessment Laboratory, U S . Environmental Protection Agency, Research Triangle Park, North Carolina 2771 1, Environmental Health Research & Testing Inc., Research Triangle Park, North Carolina, and Department of Family and Community Medicine, University of Massachusetts Medical School, Worcester, Massachusetts ~~~
Environmental tobacco smoke (ETS) has been analyzed with respect to several components following smoking of research cigarettes in an experimental chamber. Parameters analyzed and their airborne yield per cigarette included particulate matter (10 mg) and its mutagenic activity in a Salmonella bioassay, carbon monoxide (67 mg), nitrogen oxides (2 mg), nicotine (0.8-3.3 mg), formaldehyde (2 mg), acetaldehyde (2.4 mg), acrolein (0.56 mg), benzene (0.5 mg), and several unsaturated aliphatic hydrocarbons (e.g., 1,3-butadiene) of which isoprene (3.1 mg) had the highest yield. ETS from commercial cigarettes was likewise analyzed in the experimental chamber and at a public location. The relative component composition for ETS is similar when generated from either research or commercial cigarettes. All components analyzed were present a t concentrations above the background concentrations. Isoprene might be utilized as a tobacco smoke tracer for unsaturated aliphatic hydrocarbons.
Introduction Environmental tobacco smoke (ETS), which is derived primarily from sidestream smoke emitted between puffs, is a major contributor to indoor air pollution wherever smoking occurs (1, 2). ETS differs both chemically and physically from the precursor sidestream smoke, presumably due to chemical and physical transformations that occur as the mixture is diluted and aged. Chemical characterization studies have focused on mainstream and sidestream smoke (1). Data are lacking, however, on the presence and concentration of potentially toxic and carcinogenic components in tobacco-smoke-polluted indoor environments. An ideal ETS tracer air contaminant is not available for total ETS exposure (2), although nicotine is the best available tracer. In this study we investigated the concentration of a number of genotoxic components as well as potential tracers of ETS under controlled and environmental conditions. Some of the components measured are routinely monitored air pollutants including carbon monoxide, nitrogen oxides, and particulate matter. A series of aldehydes and alkenes were measured in these studies, including several that are carcinogenic. The mutagenicity of the particulate phase was assayed in Salmonella typhimurium. Nicotine was measurd as an ETS tracer. Indoor chamber experiments were performed at the EPA facility at the University of North Carolina, Chapel Hill, partly in conjunction with studies on the urinary cotinine (nicotine metabolite) concentration and excretion rate in young children following exposure to sidestream cigarette smoke 'Visiting Scientist at U.S.EPA from Nordic School of Public Health, P.O. Box 12133, S-402 42 Gothenburg, Sweden. 3 Atmospheric Research and Exposure Assessment Laboratory, US. EPA. Environmental Health Research & Testing Inc. 11 University of Massachusetts. Health Effects Research Laboratory, Genetic Bioassay Branch, MD68, U.S. EPA. 610
Environ. Sci. Technol., Vol. 23, No. 5, 1989
( 3 ) . Indoor measurements were also made in a tavern.
Experimental Section Chamber and Smoking. The tests were performed in a 13.6-m3Plexiglas chamber ( 4 ) set a t a ventilation rate of 3.55 air changes h-l; in addition, air removed by the sampling added -0.50 air changes h-l. The air in the chamber was circulated by a fan at 1.35 m3 h-l. The temperature and the relative humidity are given in Table I. Research cigarettes of the type 2R1 (51, which had been equilibrated at 22 OC at 60% relativity humidity for 48 h, were smoked by machine (RM30, Heinr. Borgwalt, Hamburg, FRG). One cigarette was lighted every 30 min and was smoked with a 35-mL puff of 2 s every minute until extinguished after 12 min. Mainstream smoke was vented to the outside of the chamber. The cigarettes weighed -1.2 g, of which 0.9-1.0 g was consumed. One adult and one child were present in the chamber during the 4-h tests in the first series of nine experiments. Six additional experiments were performed with the research cigarettes smoked by machine later in a second series, including two tests with no smoking, two tests (13 and 14) similar to the first series, (one cigarette every 30 min), and two tests (15 and 16) with one cigarette every 15 min. In tests 15 and 16, decay of components in the chamber was measured. Subsequently, in a third series of chamber tests, the emissions from two different commercial cigarette brands (A and B, both low-tar and nicotine brands) were analyzed in the chamber with regular smoking by one person without any applied ventilation. Sampling and Analysis. Particle Sampling and Analysis. Total suspended particles (TSP) were collected in duplicate on preweighed Teflon-coated glass fiber filters (Pallflex) at 1.7 m3 h-' by modified Anderson samplers consistingof the 10-mm preseparator and the backup filter. TSP was also measured continuously by an Electric Aerosol Analyzer, EAA (Thermo-System, Inc., Model 3030), with measurements taken every 9 or 10 min. Particles were also collected in triplicate with personal sampling pumps (Model P4000, Du Pont, Kennett Square, PA) at 1.7 and 3 L min-l. Nicotine. Nicotine was collected on bisulfate-impregnated fiiters (6) placed downstream from the particle filters on the personal samplers (first series) or on both Anderson and personal samplers (second series). Extraction and gas chromatography analysis of nicotine was performed as described by Hammond et al. (6). Particle Mutagenicity. The filters were extracted by sonication in dichloromethane, and the extract was brought to a fixed volume. Aliquots of the solution were distributed into 4-mL vials together with 5 pL of dimethyl sulfoxide (DMSO) and then evaporated by nitrogen gas at 35 "C. The vials were kept capped at -20 "C until bioassayed. The mutagenicity was determined by a microsuspension assay developed by Kado et al. (7) and modified by DeMarini et al. (in preparation) using Salmonella TA98 in the presence of S9 (8). The microsuspension was modified by using a bacterial suspension concentrated 5 times in-
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0013-936X/89/0923-0610$01.50/0
0 1989 American Chemical Society
Table I. Average Chamber Concentrations (fSD) and Average Airborne Yields for Carbon Monoxide, Nitrogen Oxides, Total Suspended Particles, Particle Mutagenicity, and Nicotine during Smoking of One Cigarette Every 30 Minutes (Tests 1-9, 13, and 14) and Every 15 Minutes (Tests 15 and 16) in a 13.6-maChamber with an Air Exchange of 3.55 h-l. component
series I 1-9
series I1 13 and 14
15 and 16
relative humidity, % temperature, " C carbon monoxide, mg/m3 nitric oxide, pg/m3 nitrogen oxides," pg/m3 total suspended particles, pg/m3 by mass by EAA' mutagenicity, revertants/m3 personal sampler Anderson sampler nicotine, pg/m3 personal sampler 1-9 personal sampler 13-16 Anderson sampler 13,14
53 f 4 24 f 0.5 2.48 f 0.29 68.0 f 6.OC 72.8 f 6.gC
29 f 1 23 f 0 1.79 f 0.81 61.0f 2.8 65.0 f 8.5
34 f 0 23 f 0 4.76 f 0.21 139 f 6 139 f 9
b b
349 f 39 349 f 451
321 f 25 513 f 47
934 f 46 1223 f 84
10 mg
628 f 49 494 f 58
nde 517 f 40
nd 837 f 76
17300 revertants 13400 revertants
29 f 7 nd nd
nd 127 f 23 150 f 14
nd 228 f 49 nd
800 clg 3300 pg b
airborne yield per cigarettea
67 mg b
1950 pg b
nuncorrected for surface removal. *Not applicable. cBased on eight tests. "Expressed as NO from total concentration of NO and NOz. 'Assuming unit density. 'Based on four tests. end, not determined.
stead of 10 times, 0.015 M phosphate-buffered saline instead of 0.15 M, no shaking during the 90-min incubation of the vials at 37 OC, and addition of histidine and biotin to the plate bottom agar instead of to the top agar. The combined sample from the duplicate Anderson filters from each experiment was tested with six doses corresponding to 25-300 L of air in duplicate tests with duplicate vials for each dose and test. The combined sample from the personal filters from each experiment was tested with three doses corresponding to 50-200 L of air in one test, with triplicate vials for each dose. The response was calculated by linear regression using doses on the linear or almost linear part of the dose-response curve. Carbon Monoxide and Nitrogen Oxides. Carbon monoxide (CO) was measured continuously by nondispersive infrared absorption (Bendix 8501-5), and nitrogen oxides NO, (Le., NO plus NO2) were measured indirectly by chemiluminescence(Bendix 8101-B). Data points were recorded every 3 min. Hydrocarbons. Air was collected in evacuated stainless steel canisters (9),and the sample was then subjected to speciated gas chromatographic analysis by the method described by McElroy et al. (IO). Samples in the first experimental series were collected as grab samples at a peak concentration of carbon monoxide in the chamber, whereas samples in the second series were collected over the entire smoking period (4 h). Aldehydes. Aldehydes were collected in the second series at a rate of 1.0 L min-' using 2,4-dinitrophenylhydrazine-coated silica gel cartridges for collection and high-performance liquid chromatography for analysis of the hydrazone derivatives as described by Tejada (11). Calculations. The average chamber concentrations were calculated as the average value between 1h after start until the end of the experiments. When sampling included the first hour, the average concentration was calculated by normalizing to the continuous CO concentration; this correction was approximately 5%. Likewise, grab samples of hydrocarbons were normalized to the average concentration from the peak concentration, when the sample had been collected. The airborne yield, expressed as amount per cigarette, was calculated from the average concentration by using the known smoking frequency, the chamber volume, and the total air exchange rate. Environmental Sampling. The impact of tobacco smoke was determined in two studies in a local tavern. The main room in which sampling took place had a volume
of -180 m3 ( I = 15 m, w = 4 m, and h = 3 m) and was variously occuplied by 5-25 persons, many of whom were smoking. Indoor TSP and nicotine were collected on a Tefloncoated glass fiber filter and a second bisulfate-impregnated filter, respectively, at 20 L/min by an Anderson sampler. Particulate matter was measured by taking 120-9 readings each 112 h over the 3- or 4-h study with a piezobalance Model 3500 (TSI Inc., St. Paul, MN) both indoors and outdoors with at least two cleaning cycles per hour. Indoor and outdoor carbon monoxide was determined with two General Electric Model 15ECS3C03 carbon monoxide detectors (Wilmington, MA) that had been calibrated at zero and 60 ppm CO. Indoor aldehydes and indoor and outdoor hydrocarbons were collected and analyzed as described for the chamber studies. The hydrocarbon sampling was performed during only 2 h in each of the two studies.
Results The concentrations and calculated yields are given in Table I for components that were analyzed in all chamber tests in the first and second series. Carbon monoxide and nitrogen oxides were determined continuouslyevery 3 min, and their concentrations varied in a saw-toothedform with the smoking cycle of one cigarette every 30 min. The ratio of the average maximum to the minimum concentratiuon was -3. The average concentration of carbon monoxide was about 65-70% of the maximum concentration; similar ratios were found for nitrogen oxides. Particle concentrations measured by EAA had the same type of variation, but the resolution was less because the analyses were performed less frequently. The average concentration of particles as measured by EAA (assuming unit density) was in good agreement with the concentration obtained by filter collection in the first series and overestimated the particle concentration in the second series under lower relative humidity. Due to the organic character of ETS, however, the density would be expected to be somewhat less than 1.0. The nicotine concentrations and yields were lower during the first series than during the second series, with yields of 800 pglcigarette and 3300 pglcigarette, respectively. There were several differences in the two series. In the first series, the chamber contained more adsorbant surfaces: two persons, mother and child, television set, crib, chair, and a curtain, all of which were absent in the Environ. Sci. Technol., Vol. 23, No. 5 , 1989
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Table XI. Selected Hydrocarbon Concentrations (@g/ma)in Background Air and in the 13.6" Cigarette Smoke, and Their Airborne Yields
hydrocarbon ethene ethane propene propane 1,3-butadiene isoprene benzene
erab samdes at Deak concn 1 cig'arette/30 min , , Lest av 1 2 6 concn" backgrd 65 5
116 63 74 54
2
9
105 93 71 56 24 231 38
22
