Exposure to PM_2.5 and PAHs from the Tong Liang, China Epidemiological Study

Chemically speciated PM_2.5 and particle-bound polycyclic aromatic hydrocarbon (PAH) measurements were made at three sites near urban Tong Liang, Chongqing, a Chinese inland city where coal combustion is used for electricity generation and residential purposes outside of the central city. Ambient sampling was based on 72-hr averages between 3/2/2002 and 2/26/2003. Elevated PM_2.5 and PAH concentrations were observed at all three sites, with the highest concentrations found in winter and the lowest in summer. This reflects a coupling effect of source variability and meteorological conditions. The PM_2.5 mass estimated from sulfate, nitrate, ammonium, organics, elemental carbon, crustal material, and salt corresponded with the annual average gravimetric mass within ±10%. Carbonaceous aerosol was the dominant species, while positive correlations between organic carbon and trace elements (e.g., As, Se, Br, Pb, and Zn) were consistent with coal-burning and motor vehicle contributions. Ambient particle-bound PAHs of molecular weight 168–266 were enriched by 1.5 to 3.5 times during the coal-fired power plant operational period. However, further investigation is needed to determine the relative contribution from residential and utility coal combustion and vehicular activities.

Key Words:

• PM_2.5
• Spatial distribution
• Carbonaceous aerosol
• PAH
• Coal
• China.

ACKNOWLEDGMENTS

This study was jointly sponsored by: the National Institute of Environmental Health Sciences (NIEHS) (grant #'s 5 P01 ES09600, 5 R01 ES08977, 5 R01ES11158, 5 R01 ES012468, 5 R01 ES10165), the U.S. Environmental Protection Agency (EPA) (grant #'s R827027, 82860901, RD-832141), Irving General Clinical Research Center (grant #RR00645), the Jenifer Altman Foundation, American Cancer Society, Bauman Family Foundation, Beldon Fund, the Nathan Cummings Foundation, Educational Foundation of America, Henry Ford Health Systems, Horace W. Goldsmith Foundation, the Irving A. Hansen Memorial Foundation, Gladys & Roland Harriman Foundation, W. Alton Jones Foundation, the John Merck Fund, New York City Council Speaker's Fund, the New York Community Trust, the New York Times Company Foundation, the New York Times 9/11 Neediest Fund, V. Kann Rasmussen Foundation, Rockefeller Financial Services, and the September 11th Fund of the United Way. The authors wish to thank Steven Kohl of the Environmental Analysis Facility at the Desert Research Institute (DRI) for conducting chemical analyses and performing data validation of PM_2.5 measurements; Mark Becker of Columbia University's Center for International Earth Science Information Network (CIESIN) for providing the study map; Qi Zhao and Gangcai Chen of the Chongqing Academy of Environmental Sciences and Hanqui You of the Tong Liang Environmental Protection Bureau for their work at the Tong Liang site; and Jo Gerrard and Tim Richard of DRI for assembling and editing the manuscript.

Notes

^a Pyrolyzed OC (OP) is defined as the carbon evolving between the introduction of oxygen (O₂) in the helium (He) atmosphere and the return of reflectance to its initial value (the OC/EC split).

^b OC equals OC1 + OC2 + OC3 + OC4 + OP.

^c EC equals EC1 + EC2 + EC3-OP.

^a Data for August 2002 at Site A is not available.

^b 15 U.S. EPA priority polycyclic aromatic hydrocarbons (PAHs).

^a Only retained data ≥1 ng/m³ at any given site.

^b 15 U.S. EPA priority polycyclic aromatic hydrocarbons (PAHs).

^c Ratio of coal-fired power plant operational period (from 5/10/2002 to 11/10/2002) to coal-fired power plant non-operational period.

^d Not available.