SHORT-TERM AIR-POLLUTION EXPOSURES AND RESPONSES IN LOS-ANGELES AREA SCHOOLCHILDREN

We studied 269 school children from three Southern California communit ies of contrasting air quality in two successive school years, to inve stigate short-term effects of ambient ozone (O-3), nitrogen dioxide (N O2), or particulate matter (PM) on respiratory health. We measured lun g function and symptoms twice daily for one week each infall, winter a nd spring; and concurrently assessed time-activity patterns and person al exposures. Average daily personal exposures correlated with polluta nt concentrations at central sites (r=0.61 for O-3 0.63 for NO2 0.48 f or PM). Questionnaire-reported outdoor activity increased slightly in communities/seasons with higher pollution. Lung function differences b etween communities were explainable by age differences. Morning forced vital capacity (FVC) decreased significantly with increase in PM or N O2 measured over the preceding 24 hours. Morning-to-afternoon change o f forced expired volume in one second (FEV(1)) became significantly mo re negative with increase in PM, NO2, or O-3 on the same day Predicted FVC or FEV(1) loss on highest- vs lowest-pollution clays was <2%. Dai ly symptoms showed no association with current or prior 24-hour pollut ion, but increased with decreasing temperature. Parents' questionnaire responses suggested excess asthma and allergy in children from one po lluted community while children in the other polluted community report ed more symptoms, relative to the cleaner community. We conclude that Los Angeles area children may experience slight lung function changes in association with day-to-day air quality changes, reasonably similar to responses seen by others in less polluted areas. Although short-te rm pollution effects appear small, they should be assessed in longitud inal lung function studies when possible, to allow maximally accurate measurement of longer-term function changes.