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 PM₁₀, PM_2.5, elements, elemental/organic carbon, and criteria gases (NO₂, SO₂, and O₃) 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 (O₃, PM_10, PM_2.5, and S); after adjustment for O₃, 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 (O₃, PM₁₀, PM_2.5, Na, and S); after adjustment for O₃, only Na and S remained significant. Reduced pulmonary function was significantly associated with O₃ 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.