The effects of components of fine particulate air pollution on mortality in california: results from CALFINE.
OBJECTIVE
Several epidemiologic studies provide evidence of an association between daily mortality and particulate matter < 2.5 pm in diameter (PM2.5). Little is known, however, about the relative effects of PM2.5 constituents. We examined associations between 19 PM2.5 components and daily mortality in six California counties.


METHODS
We obtained daily data from 2000 to 2003 on mortality and PM2.5 mass and components, including elemental and organic carbon (EC and OC), nitrates, sulfates, and various metals. We examined associations of PM2.5 and its constituents with daily counts of several mortality categories: all-cause, cardiovascular, respiratory, and mortality age > 65 years. Poisson regressions incorporating natural splines were used to control for time-varying covariates. Effect estimates were determined for each component in each county and then combined using a random-effects model.


RESULTS
PM2.5 mass and several constituents were associated with multiple mortality categories, especially cardiovascular deaths. For example, for a 3-day lag, the latter increased by 1.6, 2.1, 1.6, and 1.5% for PM2.5, EC, OC, and nitrates based on interquartile ranges of 14.6, 0.8, 4.6, and 5.5 pg/m(3), respectively. Stronger associations were observed between mortality and additional pollutants, including sulfates and several metals, during the cool season.


CONCLUSIONS
This multicounty analysis adds to the growing body of evidence linking PM2.5 with mortality and indicates that excess risks may vary among specific PM2.5 components. Therefore, the use of regression coefficients based on PM2.5 mass may underestimate associations with some PM2.5 components. Also, our findings support the hypothesis that combustion-associated pollutants are particularly important in California.
Ostro
Bart
B
Office of Environmental Health Hazard Assessment, 16th Floor, 1515 Clay St., Oakland, CA 94612, USA. Bostro@oehha.ca.gov
Feng
Wen-Ying
WY
Broadwin
Rachel
R
Green
Shelley
S
Lipsett
Michael
M
D000368:Aged; D000393:Air Pollutants / Q000032:analysis / Q000633:toxicity*; D000397:Air Pollution / Q000009:adverse effects* / Q000032:analysis; D002140:California / Q000453:epidemiology; D002244:Carbon / Q000032:analysis / Q000633:toxicity; D002318:Cardiovascular Diseases / Q000209:etiology / Q000401:mortality; D002947:Cities; D004784:Environmental Monitoring; D062665:Epidemiological Monitoring; D006801:Humans; D008670:Metals / Q000032:analysis / Q000633:toxicity; D009026:Mortality; D009566:Nitrates / Q000032:analysis / Q000633:toxicity; D010316:Particle Size; D052638:Particulate Matter / Q000032:analysis / Q000633:toxicity*; D012140:Respiratory Tract Diseases / Q000209:etiology / Q000401:mortality; D013431:Sulfates / Q000032:analysis; D001335:Vehicle Emissions
D000393:Air Pollutants; D008670:Metals; D009566:Nitrates; D052638:Particulate Matter; D013431:Sulfates; D001335:Vehicle Emissions; D002244:Carbon