Outdoor air pollution and health effects in urban children with moderate to severe asthma

Particulate matter less than 2.5 μm in diameter (PM 2.5 ) is associated with asthma morbidity. Recent studies have begun examining the role of various constituents of PM 2.5 , their potential sources, and their effects on health. We examine their role in asthmatic children. Thirty-six children 6–14 years with moderate/severe asthma from inner city areas in New York City were studied for 2-week periods (summer and winter) using diaries and lung function. Outdoor data, including PM 10 , PM 2.5 , elements, elemental/organic carbon, and criteria gases (NO 2 , SO 2 , and O 3 ) were collected at two sites. Odds ratios (ORs) relating daily pollutant concentrations to asthma indicators were calculated. During summer significant ORs>1 for symptom severity were obtained (O 3 , PM 10, PM 2.5 , and S); after adjustment for O 3 , the ORs were no longer significant. During winter, Cu, Fe, Si, and Zn were significantly but negatively (ORs<1) associated with symptoms. Lag effects in winter suggested delayed effects (ORs>1) on symptoms (As, K, Pb, and V). Albuterol use increased during summer (O 3 , PM 10 , PM 2.5 , Na, and S); after adjustment for O 3 , only Na and S remained significant. Reduced pulmonary function was significantly associated with O 3 and Cl. Components of PM 2.5 are associated with asthma exacerbation in asthmatic children. Same-day pollutant associations with symptoms are seen in summer. In winter, our analysis suggests delayed adverse associations of PM 2.5 components.