Short-term associations between ambient air pollutants and pediatric asthma emergency department visits.
BACKGROUND
Certain outdoor air pollutants cause asthma exacerbations in children. To advance understanding of these relationships, further characterization of the dose-response and pollutant lag effects are needed, as are investigations of pollutant species beyond the commonly measured criteria pollutants.


OBJECTIVE
Investigate short-term associations between ambient air pollutant concentrations and emergency department visits for pediatric asthma.


METHODS
Daily counts of emergency department visits for asthma or wheeze among children aged 5 to 17 years were collected from 41 Metropolitan Atlanta hospitals during 1993-2004 (n = 91,386 visits). Ambient concentrations of gaseous pollutants and speciated particulate matter were available from stationary monitors during this time period. Rate ratios for the warm season (May to October) and cold season (November to April) were estimated using Poisson generalized linear models in the framework of a case-crossover analysis.


RESULTS
Both ozone and primary pollutants from traffic sources were associated with emergency department visits for asthma or wheeze; evidence for independent effects of ozone and primary pollutants from traffic sources were observed in multipollutant models. These associations tended to be of the highest magnitude for concentrations on the day of the emergency department visit and were present at relatively low ambient concentrations.


CONCLUSIONS
Even at relatively low ambient concentrations, ozone and primary pollutants from traffic sources independently contributed to the burden of emergency department visits for pediatric asthma.
Strickland
Matthew J
MJ
Department of Environmental and Occupational Health, Atlanta, GA 30322, USA. mjstric@emory.edu
Darrow
Lyndsey A
LA
Klein
Mitchel
M
Flanders
W Dana
WD
Sarnat
Jeremy A
JA
Waller
Lance A
LA
Sarnat
Stefanie E
SE
Mulholland
James A
JA
Tolbert
Paige E
PE
D000293:Adolescent; D000393:Air Pollutants / Q000032:analysis / Q000633:toxicity*; D001249:Asthma / Q000453:epidemiology*; D002648:Child; D002675:Child, Preschool; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data*; D004784:Environmental Monitoring; D062665:Epidemiological Monitoring; D005845:Georgia / Q000453:epidemiology; D006801:Humans; D016014:Linear Models; D010126:Ozone / Q000032:analysis / Q000633:toxicity; D052638:Particulate Matter / Q000032:analysis / Q000633:toxicity; D012135:Respiratory Sounds; D012621:Seasons; D001335:Vehicle Emissions / Q000032:analysis / Q000633:toxicity
D000393:Air Pollutants; D052638:Particulate Matter; D001335:Vehicle Emissions; D010126:Ozone