Changes of PM2.5 population exposure and its sources in the US from 1990 to 2010

KEYWORDS PM25, air pollution sources, exposure BACKGROUND AND AIM The quantification of the contributions of sources of air pollutants, especially PM2.5, can be used for the improvement of our understanding of PM2.5 health effects. Three-dimensional chemical transport models are well suited to address this problem, since they simulate all the major processes that impact PM2.5 concentrations and transport. In this work, we quantified the changes in the concentration, exposure, composition, and sources of PM2.5 in the US. Significant reductions of emissions of SO2, NOx, VOCs and primary PM have taken place. METHODS We evaluate our understanding of the links between these emissions concentration and exposure changes combining a chemical transport model (PMCAMx) with the Particle Source Apportionment Algorithm. RESULTS Results for 1990, 2001 and 2010 are presented. The 63% reduction in PM2.5 sulfate concentrations from electrical generation units during these 20 years has led to a 60% reduction in PM2.5 sulfate exposure. Also, the reductions in elemental carbon (EC) concentrations from road transport by 72% have led to a reduction of PM2.5 EC exposure of 70%. CONCLUSIONS In 1990 90% of the US population was exposed to PM2.5 concentrations to equal and higher than the suggested annual mean by the WHO, but this reduced to 70% in 2010. These results are the basis for an epidemiological study linking PM2.5 sources in the US and their health effect (Pond et al., 2021). REFERENCES Pond, Z. A., Hernandez, C. S., Adams, P. J., Pandis, S. N., Garcia, G. R., Robinson, L. A., Marshall, J. D., Burnett, R., Skyllakou, K., Rivera, P. G., Karnezi, E., Coleman, C. J., and Pope, A. C.: Cardiopulmonary Mortality and Fine Particulate Air Pollution by Species and Source in a National U.S. Cohort, Env. Science & Tech. Article ASAP, 2021.