Background: Although several cohort studies report associations between chronic exposure to fine particles (PM_2.5) and mortality, few have studied the effects of chronic exposure to ultrafine (UF) particles. In addition, few studies have estimated the effects of the constituents of either PM_2.5 or UF particles.

Methods: We used a statewide cohort of > 100,000 women from the California Teachers Study who were followed from 2001 through 2007. Exposure data at the residential level were provided by a chemical transport model that computed pollutant concentrations from > 900 sources in California. Besides particle mass, monthly concentrations of 11 species and 8 sources or primary particles were generated at 4-km grids. We used a Cox proportional hazards model to estimate the association between the pollutants and all-cause, cardiovascular, ischemic heart disease (IHD), and respiratory mortality.

Results: We observed statistically significant ( p < 0.05) associations of IHD with PM_2.5 mass, nitrate, elemental carbon (EC), copper (Cu), and secondary organics and the sources gas- and diesel-fueled vehicles, meat cooking, and high-sulfur fuel combustion. The hazard ratio estimate of 1.19 (95% CI: 1.08, 1.31) for IHD in association with a 10-μg/m³ increase in PM_2.5 is consistent with findings from the American Cancer Society cohort. We also observed significant positive associations between IHD and several UF components including EC, Cu, metals, and mobile sources.

Conclusions: Using an emissions-based model with a 4-km spatial scale, we observed significant positive associations between IHD mortality and both fine and ultrafine particle species and sources. Our results suggest that the exposure model effectively measured local exposures and facilitated the examination of the relative toxicity of particle species.

Citation: Ostro B, Hu J, Goldberg D, Reynolds P, Hertz A, Bernstein L, Kleeman MJ. 2015. Associations of mortality with long-term exposures to fine and ultrafine particles, species and sources: results from the California Teachers Study cohort. Environ Health Perspect 123:549–556;  http://dx.doi.org/10.1289/ehp.1408565

Address correspondence to B. Ostro, OEHHA, 2008 Tampa Ave., Oakland, CA 94611 USA. Telephone: (510) 339-3379. E-mail: bostro@pacbell.net

Funding for this effort was provided by grant R01 CA77398 from the National Cancer Institute, contract 97-10500 from the California Breast Cancer Research Fund, and STAR grant R833372 from the U.S. Environmental Protection Agency (EPA).

Although the research described in the article has been partially funded by the U.S. EPA, it has not been subject to the agency’s required peer and policy review and therefore does not necessarily reflect the views of the agency and no official endorsement should be inferred. All PM_2.5 and ultrafine PM exposure data used in the present study is available free of charge at http://faculty.engineering.ucdavis.edu/k​leeman/ .

The authors declare they have no actual or potential competing financial interests.

Received: 15 April 2014 Accepted: 22 January 2015 Advance Publication: 23 January 2015 Final Publication: 1 June 2015