The purpose of this study is to assess the effect of long-term concentrations of ambient PM on risks of all causes, cardiopulmonary, coronary heart disease (CHD), total cancer, and any mention of nonmalignant respiratory disease (NMRD) mortality.
The health effects of long-term ambient air pollution have been studied with up to 30 years of follow-up in the AHSMOG cohort, a cohort of 6,338 nonsmoking white California adults. Monthly concentrations of ambient air pollutants [particulate matter <10 μm in aerodynamic diameter (PM10), Ozone (O3), sulfur dioxide (SO2), nitrogen dioxide (NO 2) or particulate matter <2.5 μm in aerodynamic diameter (PM 2.5)] were obtained from monitoring stations or airport visibility data (for PM2.5) and interpolated to ZIP code centroids of work and residence locations. All participants were asked to complete a detailed lifestyle questionnaire at baseline (1976). Follow-up information on environmental tobacco smoke and other personal sources of air pollution was available from four subsequent questionnaires from 1977 to 2000.
In the AHSMOG cohort, each increment of 10 μg/m3 in PM10 in two-pollutant models showed increased risks of fatal NMRD with the relative risk (RR) of 1.13 [95% confidence interval (CI), 1.04-1.22], 1.05 (95% CI, 0.98-1.13) or 1.06 (95% CI, 0.99-1.14) controlling for O 3, NO2 or SO2, respectively. Also the RR of cancer mortality for each increment of 30 days/year of PM10 in excess of 100 μg/m3 was 1.16 (95% CI: 1.03-1.31).
In the AHSMOG airport subcohort (n=3,239), the RR for fatal CHD with each 10 μg/m3 increase in PM2.5 was 2.00 (95 % CI: 1.51, 2.64) in the two pollutant model with O3 in females. Corresponding RR’s for a 10 ìg/m3 increases in PM 10-2.5 and PM10 were 1.62 and 1.45, respectively, in all females. No significant associations were found in males.
A positive association with fatal CHD was found with all three PM fractions in females, but not in males. The risk estimates were more significant after adjustment for gaseous pollutants, especially O3. The risk estimates were the highest for PM2.5. Also, increased risks of NMRD and cancer mortality were found with ambient levels of PM10 and gases (O3, or SO2).