Fungus spores, air pollutants, and other determinants of peak expiratory flow rate in children.
The impact of summertime haze episodes on daily variations in symptoms and peak expiratory flow rates (PEFRs) was examined in a study of 108 children living in State College, Pennsylvania, during the summer of 1991. Twice daily, each child recorded symptoms, PEFRs and hours spent outdoors. Environmental measurements included daily 12- and 24-hour averages for meteorologic and air pollutant variables and 24-hour average fungus spore concentrations. A 10,000-spore/m3 increment in Cladosporium spore concentration was associated with a deficit in morning PEFR (-1.0 liters/minute, 95% confidence interval (CI) -1.9 to -0.2). A 60-spore/m3 increment in Epicoccum spore concentration was associated with increased incidence of morning cough (odds ratio (OR) = 1.8, 95% CI 1.0-3.2) and a deficit in morning PEFR (-1.5 liters/minute, 95% CI -2.8 to -0.2). Fungi spore counts were not associated with respirable particle mass. A 125-nmol/m3 increment in 12-hour daytime particle-strong acidity was associated with a deficit in evening PEFR (-0.5 liters/minute, 95% CI -1.2 to 0.2) and increased incidence of cold episodes that evening or the subsequent morning (OR = 1.35, 95% CI 1.14-1.61). A 20-microgram/m3 increment in 24-hour respirable particles lagged by 24 hours was associated with a deficit in evening PEFR (-0.5 liters/minute 95% CI -1.4 to 0.4) and increased incidence of cough episodes that evening or the subsequent morning (OR = 1.37, 95% CI 1.13-1.66). These results confirm the acute effects of summertime particulate air pollution and suggest that aeroallergens have independent effects on respiratory symptoms and PEFR in children.