title: Effects of air pollution on emergency room visits for respiratory illnesses in Montreal, Quebec.
abstract: As an approach to evaluating the public health burden from current air pollution levels, we examined the relationship of daily emergency room (ER) visits for respiratory illnesses (25 hospitals, average 98 visits/d) to air pollution in Montreal, Canada, from June through September, 1992 and 1993. Air pollutants measured included ozone (O3), particulate matter diameter < 10 microm (PM10) and < 2.5 microm (PM2.5), the sulfate fraction of PM2.5 (SO4), and aerosol strong acidity (H+). Temporal trends, autocorrelation, and weather were controlled for in time-series regressions. For 1992, no significant associations with ER visits were found. However, 33% of the particulate data were missing. For 1993, 1-h maximum O3, PM10, PM2.5, and SO4 were all positively associated with respiratory visits for patients over 64 yr of age (p < 0.02). An increase to the mean level of 1-h maximum O3 (36 ppb) was associated with a 21% increase over the mean number of daily ER visits (95% confidence interval [CI]: 8 to 34%). Effects of particulates were smaller, with mean increases of 16% (4 to 28%), 12% (2 to 21%) and 6% (1 to 12%) for PM10, PM2.5, and SO4, respectively. Relative mass effects were PM2.5 > PM10 >> SO4. Ozone and PM10 levels never exceeded 67 ppb and 51 microg/m3, respectively (well below the U.S. National Ambient Air Quality Standards of 120 ppb and 150 microg/m3, respectively). The present findings have public health implications with regard to the adverse health effects of urban photochemical air pollution on older individuals.
authors.affiliation: Department of Medicine, University of California, Irvine, USA.
authors.forename: R J
authors.initials: RJ
authors.lastname: Delfino
authors.forename: A M
authors.initials: AM
authors.lastname: Murphy-Moulton
authors.forename: R T
authors.initials: RT
authors.lastname: Burnett
authors.forename: J R
authors.initials: JR
authors.lastname: Brook
authors.forename: M R
authors.initials: MR
authors.lastname: Becklake
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000393:Air Pollutants / Q000009:adverse effects* / Q000032:analysis; D002648:Child; D002675:Child, Preschool; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data*; D004812:Epidemiologic Methods; D005260:Female; D006801:Humans; D007223:Infant; D008171:Lung Diseases / Q000453:epidemiology / Q000209:etiology*; D008297:Male; D008875:Middle Aged; D010126:Ozone / Q000032:analysis; D011792:Quebec / Q000453:epidemiology; D014504:Urban Health
chemical_list: D000393:Air Pollutants; D010126:Ozone