Journal of Exposure Analysis and Environmental Epidemiology (1999) 9,293±299 # 1999 Stockton Press All rights reserved 1053-4245/99/$12.00 http://www.stockton-press.co.uk Respiratory function as measured by peak expiratory flow rate and PM10: six communities study JONG-TAE LEE a,b AND CARL M. SHYa a Department of Epidemiology, School of Public Health, University of North Carolina, Chapel Hill, NC b Department of Preventive Medicine, College of Medicine, Yonsei University, Seoul, Korea This Six Communities Studyconducted at six communities in southwestern North Carolina investigates the respiratoryhealth status of residents who se households are located near an incinerator. This diarystudymakes it possible to estimate the dailyvariation of pulmonaryfunction measured as peak expiratory flow rate (PEFR) related to 24-h mean PM10 levels, which were observed at each monitoring station placed in the six studycommunities, as a surrogate exposure measure of outdoor air pollution. Observations of PEFR among participants in each communitywere analyzedto determine how theyvaried according to the degree of exposure to ambient pollutants as well as to other cofactors including, sex, age, respiratoryhypersensitivity,hours spe nt outdoors within the area of the selected community, and surrogate measures for indoor air pollution exposure (vacuum use and experience of air irritants at work). The findings revealed that respiratoryhypersensitivitystatus is a predictor of declining PEFR. PM 10 concentrations measured in each studyarea did not seem to be related to the variations of respiratoryhealth as measured byPEFR. This studydid not show anydifference in respiratoryhealth between subjects of a n incinerator communityand those of its comparison community.Even though this community-based studywith free-living subjects shows negative find ings on the relationship between respiratoryhealth and PM 10, it is worth noting that these findings must be interpreted cautiouslybecause exposure estimation based on monitoring of ambient air likelyresults in misclassification of true exposure levels. Keywords: air pollution, environmental epidemiology, epidemiologic methods, incinerators, longitudinal data, particulate matters, PEFR, respiratory function. Introduction nominal 10 m (PM10). The study, however, failed to see an association between the prevalence of acute respiratory symptoms and these pollutants. Because the volume of inhaled air is so large, a biologically Incineration, disposing about 10% of solid waste in the significant dose of a potentiallyhazardous contaminant may United States, is an important and useful method for be delivered to the respiratorytract even though the destroying any type of hazardous waste (Environmental contaminant is present in the air at a low concentration. Protection Agency, 1986). A total of 260 hazardous waste Studies of trends over time in air pollution and disease incinerators were operating throughout the countryin 1986 patterns have produced a growing bodyof literature that has (Environmental Protection Agency, 1986). Pollutants associated day-to-day fluctuations in air pollution with daily emitted from an incinerator stack are particulate matter, fluctuations in acute morbidityor mortality(Whittemore carbon monoxide, hydrogen chloride, sulfur dioxide, and Korn, 1980; Dockeryand Schwartz, 1992; Schwartz nitrogen oxides, various metals, dioxins/furans, and volatile and Dockery, 1992 ; Schwartz et al., 1993). The acute organic compounds (VOCs). Much of the data that we have respiratoryeffects of ambient winter air pollution episodes on adverse health effects from exposure to incinerated waste were studied in a sample of children aged 7±12 years old in comes from cases of accidental or exceptionallyhigh levels nonindustrial communities in the Netherlands (Hoek and of exposure to pollutants. There is good evidence that Brunekreef, 1994). The studyreported significant negative particulate matter and other combustion products released associations between pulmonaryfunction and the concen- byindustrial sources can produce chronic respiratory tration of sulfur dioxide (SO ), black smoke, and particulate 2 disease (Environmental Protection Agency, 1982). Building matter with an aerodynamic diameter equal to or less than a a new incinerator, therefore, is often controversial because of concerns related to the possibilityof adverse health 1. Address all correspondence to: Dr. Jong-Tae Lee, Department of effects and environmental contamination from long-term Preventive Medicine and Public Health, College of Medicine, Yonsei exposure to these pollutants. University, 134 Shinchon-Dong, Seodaemun-Gu, Seoul, South This studyis a community-based diarystudyand uses a Korea. Tel.: +82-2-361-5357. Fax: +82-2-392-0239. E-mail: [email protected] classic design for the respiratoryeffects of air pollution. The Accepted 20 November 1998. studydesign consisted of a cross-sectional survey,yearly Lee and Shy Respiratoryfunction as measured bypeak expiratoryflow rate and PM 10: six communities study repeated cross-sectional observations (baseline spirometry sities. Three comparison communities were rep resented by information), and longitudinal information for 5 weeks in the labels MCo, BCo, and HCo. There is no other major air each year of follow-up. Over cross-sectional studies, the pollution source in these selected communities, except those longitudinal methods have a unique benefit of which the incinerators. possibilityof confounding byother time-varyingfactors At each studysite, we contacted everyselected house- that are difficult to control maybe reduced. The analyses hold byan introductoryletter, followed bypersonal home presented here address the following research questions. (1) and telephone interviews. The participants were informed Is the outdoor PM10 level associated with respiratory that theywere part of an environmental study,but no function, as measured bypeak expiratoryflow rate (PEFR)? reference was made to the area incinerator as a pollution (2) Are some indoor sources of air pollution in the source of interest. Through the telephone interview, we workplace or home associated with PEFR? (3) Does the obtained information on sociodemographic factors, smok- lung function of participants in an incinerator community ing habits, respiratorysymptoms compatible with chronic differ from that in its comparison community? (4) Are the obstructive lung disease or with respiratoryhypersensitivity, results more conclusive or different when anyquestion frequencyof lower respiratorytract disease over the past described above is applied onlyto a subgroup of participants 2 years, other medical conditions, occupation and place with respiratory hypersensitivity? This study investigated of work as well as potential for exposure to irritating each of these research questions byanalyzing the respiratory substances at work, and perception of neighborhood function measured as PEFR of the original longitudinal data environmental pollution associated with respiratorysymp- of the Health and Clean Air (HCA) studyduring 1992±1993 toms. We identified active smokers and persons usually in all six communities (Shyet al., 1995). exposed to tobacco smoke at home, and excluded these subjects from the follow-up study. Based on information obtained from the community- wide cross-sectional survey, about 80 subjects aged 8±80 in Methods and materials each communitywere selected and asked to participate in the 1-month longitudinal study. The 80 subjects were This studyused a longitudinal component from the HCA selected such that half of them gave a positive response on studyconducted in southwestern North Carolina during the question regarding wheezing or asthma-like symptoms 1992 and 1993. All information were obtained from during the past 12 months, and the other half included nonsmoking participants. Participants were instructed to persons who did not have anyactive respiratorydisorders. perform the peak flow test three times in the standing The former subjects were termed `respiratory-hypersensi- position, twice daily(in the morning and in the evening), tives' and the latter `normals'. All selected subjects were and to report simple time±activitypatterns of the day.Daily neither active nor passive smokers. The baseline assessment measurements of 24-h average PM concentrations were 10 of lung function was done with routine spirometryusing a obtained from an air sampling tower in each study computerized dryrolling seal spirometer. Each subject was communityduring the month of the longitudinal study. provided with a mini-Wright peak flow meter (Clement Clark, Inc., Columbus, OH) and a preformatted health Subject Selection and Health Outcomes symptom diary for 5 weeks, and was trained on their proper Based on aerial photographs and site visits, we located three use. Participants were instructed to perform the peak flow paired communities. There were about 400±500 homes in test three times in the standing position, twice daily(in the each selected community. Each pair of communities morning and in the evening), and to record all the readings consisted of a target (exposed, or incinerator community) along with the symptoms experienced that day, any and a comparison (nonexposed) area. This studywas medication use, and simple time±activitypatterns of the directed at the population surrounding three distinct waste day. Respiratory and nonrespiratory symptoms were listed combustion facilities; two located in Mecklenburg County, on the diaryform, with following