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Nevalainen, T.; Koistinen, J. Chemosphere 1991, 23, 1581-1589. Koistinen, J. Chemosphere 1992, 24, 559-573. Herve, 5. Ph.D. Dissertation, Research Report No. 36, Department of Chemistry, University of Jyvbkyla, 1991; p 36. Koistinen, J.; Paasivirta, J.; Slirkkii, J. Chemosphere 1990, 21, 1371-1379. Nevalainen, T.; Koistinen, J. Proceedings of a SEPA Conference, Environmental fate and effects of bleached pulp mill effluents, Stockholm, Sweden, Nov 19-21,1991; pp 164-167. Koistinen, J.; Paasivirta, J. Ertended Abstracts, 12th International Mass Spectrometry Conference, Amsterdam, Aug 26-30,1991; p 54. Sinkkonen, S.; Koistinen, J. Chemosphere 1990, 21, 1161-1171. Bundt, J.; Herbel, W.; Steinhard, H. J . High Resolut. Chromatogr. 1991, 14, 91-97. Bjermth, A.; Carlberg, G. E.; Merller, M. Sci. Total Environ. 1979,11,197-211. Koistinen, J.; Paasivirta, J. Abstracts, DIOXIN'91, 11th International Symposium on Chlorinated Dioxins and Related Compounds, Sept 23-27,1991; Research Triangle Park, NC, 1991; p 338. Men, L. H.; Berry, R. M.; Fleming, B. I.; Luthe, C. E.; VW, R. H. Chemosphere 1989,19,741-744. Sinkkonen, S.; Paasivirta, J.; Koistinen, J.; LahtiperB, M.; Lammi, R. Chemosphere 1992,24, 1755-1763.
Acknowledgments
Dr. Sirpa Herve (Water and Environment District of Central Finland) is gratefully acknowledged for the mussels, Ms. Mirja Lahtipera (University of Jyviiskyla) for HRMS with VG Autospec, and Professor Jaakko Paasivirta (University of Jyviiskyla) for reviewing the manuscript. Literature Cited Leach, J. M.; Thakore, A. N. J. Fish. Res. Board Can. 1975, 32, 1249-1257. Lindstrom, K.; Nordin, J. J. Chromatogr. 1976,128,13-26. Bjerrseth, A.; Lunde, G.; Gjm,N. Acta Chem. Scand. B. 1977, 31, 797-801. Knuutinen, J. Ph.D. Dissertation,Research Report No. 18, Department of Chemistry, University of Jpbkyla, 1984. Kringstad, K. P.; Lindstrom, K. Environ. Sci. Technol. 1984, 18,236A-248A. Maatela, P. Lic. Phil. Thesis, University of Jyviiskylii, 1992. Beck, H.; Eckart, K.; Mathar, W.; Wittkowski, R. Chemosphere 1988, 17, 51-57. Swanson, S.E.; Rappe, C.; Malmstrom, J.; Kringstad, K. P. Chemosphere 1988, 17, 681-691. Clement, R. E.; Tashiro, C.; Suter, S.; Reiner, E.; Hollinger, D.Chemosphere 1989,18, 1189-1197. Kuehl, D. W.; Butterworth, B. C.; DeVita, W. M.; Sauer, C. P. Environ. Sci. Technol. 1987, 14, 443-447. Buser, H.-R.; Kjeller, L.-0.; Swanson, S. E.; Rappe, C. Environ. Sci. Technol. 1989, 23, 1130-1137. Beck, H.; Dross, A.; Eckart, K.; Mathar, W.; Wittkowski, R. Chemosphere 1989,19, 655-660.
Received for review April 28,1992. Revised manuscript received July 28, 1992. Accepted August 31, 1992. This research was supported financially by the Natural Science Council of the Academy of Finland.
Personal Exposures to Acid Aerosols and Ammonia Helen H. Suh," John D. Spengler, and Petros Koutrakls
Harvard School of Public Health, 665 Huntlngton Avenue, Boston, Massachusetts 021 15 Indoor, outdoor, and personal acid aerosol monitoring was performed for 24 children living in Uniontown, PA, during summer 1990. These measurements were used to investigate the magnitude of personal acid aerosol exposures and its relationship to indoor and outdoor concentrations. Indoor, outdoor, and personal measurements were compared to outdoor measurements collected from a centrally located, stationary ambient monitoring site. Personal exposures reached a maximum of 300 nm01.m-~ for both sulfate and aerosol strong acidity (12-h daytime measurements). Personal exposures were lower than corresponding outdoor levels and higher than indoor levels, with differences being greater for aerosol strong acidity. Air conditioning was found to be an important predictor of indoor sulfate and aerosol strong acidity, while ammonia was found to influence indoor and personal aerosol strong acidity concentrations. Time/activity weighted models of indoor and outdoor concentrations were used to predict personal sulfate and aerosol strong acidity exposures. These models predicted personal sulfate and aerosol strong acidity exposures substantially better than outdoor concentrations done. The aerosol acidity model, however, was unable to explain all the variability in personal exposures. Research should be conducted to determine the effects of particle loss and ammonia neutralization around the human body. Introduction Acid aerosols have received considerable attention over recent years. In the past, studies have focused on their 0013-936X/92/0926-2507$03.00/0
adverse effects to trees, lakes, and visibility; however, more recent efforts have examined their potential deleterious effects to humans. Several controlled laboratory studies in both humans and animals have demonstrated that exin posures to acid aerosols, aerosol strong acidity (H+) particular, may compromise the respiratory system (1-7). Results from epidemiologic studies have been inconsistent and less definitive, but suggest that acid aerosol exposures may result in decrements in pulmonary function, increased hospital admissions for asthma and other respiratory ailments, and possibly excess mortality, as experienced during the 1952 London fog episode (8-12). These health studies underscore the need to characterize personal exposures to acid aerosols. Information on the magnitude and duration of individual acid aerosol exposures will improve risk estimates for both individuals and populations. In addition, personal exposure characterization will help identify factors, such as housing characteristics, personal habits, and activity patterns, that influence acid aerosol exposures. Once identified, these factors can be incorporated into exposure models, which then can be used to obtain improved estimates of health risks when only limited exposure information is known. Epidemiologic air pollution studies, for example, typically use air pollutant measurements collected from a stationary ambient monitor to reflect exposures for surrounding populations, often for entire communities. Ambient measurements may not capture spatial variation in outdoor concentrations. Moreover, outdoor concentration measurements will ignore the often important contribution
0 1992 Amerlcan Chemical Society
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Fburr 1. Home monitoring schedule. SAM represents the stationary ambient monitoring site. Sampling schedule each week is Mentical to that for week 1. Home sampling is identical to that for home 1.
of indoor concentrations on personal exposures. Consequently, personal exposure estimates based on ambient concentrations alone may result in substantial misclassification of the exposure status of study subjects (13-15). Reducing this misclassificationthrough the use of personal monitoring or personal exposure models will increase the statistical power of epidemiologic studies to detect exposure/disease relationships and ultimately will improve estimates of health risk. In this paper, we evaluated the ability of outdoor measurements to estimate personal exposures to sulfates and aerosol strong acidity. We collected daily indoor, outdoor, and personal acid aerosol measurements and time/activity pattern data for 24 children living in Uniontown, PA, during summer 1990. These children were identified from the cohort of participants in the Children’s Summer Health Study, a concurrent investigation of air pollution (acid aerosols, ozone, particulates) and pulmonary performance. As part of the health study, exposures were estimated for 99 children using air pollutant concentrations measured at a single outdoor monitoring site. Personal, indoor, and outdoor measurements for the 24 children were compared to measurements collected from the stationary ambient monitoring site. Factors that may influence indoor and personal concentrations were identified and were incorporated into indoor concentration estimates and personal exposure models. The accuracy and precision of the personal exposure models was evaluated and compared to that of outdoor concentrations alone.
Methods Uniontown, PA, is a small, semirural community (population 14OOO) located 60 km southeast of Pittsburgh and 90 km east of the Ohio River. No major air pollution sources are located within Uniontown; however, large regional sources, including Pittsburgh, the Ohio River valley, and the industrialized Monongahela river (17-25 km to the west and northwest) may impact air pollution concentrations in Uniontown. Monitoring Sites. Indoor, outdoor, and personal monitoring was performed for 24 children participating in 2508
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the Children’s Summer Health Study. These children lived in homes located throughout the Uniontown area. All children lived in nonsmoking households, and approximately half (11out of 24) lived in air-conditioned homes. Three of the children’s homes had gas stoves. Additional outdoor monitoring was conducted at a stationary ambient monitoring (SAM) site as part of the health study. The SAM site was centrally located, as all homes were within a radius of 16 km and an altitude of 33 m of this SAM site. Sampling Period. Monitoring was conducted at the homes on 27 days during the summer of 1990, with two homes monitored each day (Figure 1). Each home was monitored over a 2-day period, during which four 12-h indoor, two 24-h outdoor, and two 12-h personal samples were collected. Four 12-h samples also were collected at the SAM site during this period. All indoor and outdoor samples r a n continuously, beginning or ending at 8 a.m. or 8 p.m. Personal samples were collected on each monitoring day from 8 a.m. to 8 p.m. Indoor and Outdoor Sampling. Indoor and outdoor samplers were placed in the living room and backyard of each home, respectively. Samples were collected at a flow rate of 10 L-min-l using the Harvard-EPA annular denuder system (HEADS). HEADS simultaneously collects the gases ammonia (NH,), nitric acid (HNO,), nitrous acid (HONO), and sulfur dioxide (SO,) and particulate nitrate (NO
