Characterization of complex mixtures in urban atmospheres for inhalation exposure studies

This paper discusses the importance of comprehensive characterization of ambient PM2.5, CAPs and their sources, and the associated challenges. In a southwest Detroit community where the pediatric asthma rate is about three times the national average, a detailed assessment was performed including: characterization of ambient PM2.5 and CAPs; identification of major emission sources of PM2.5; and quantification of trace elements in lung tissues of laboratory rats that were exposed to CAPs, all in an effort to define source-receptor pathways for ambient PM2.5. Our findings to date constitute evidence of the retention of ambient urban particulates from local combustion sources within animal tissues from short-term exposures, and possible associations between the observed health effects and source-specific PM2.5. However, a complete understanding of the effects of complex mixtures of air pollutants and their toxicological impacts still faces many challenges.