US EPA

10273 

Journal Article 

Association between particulate- and gas-phase components of urban air pollution and daily mortality in eight Canadian cities 

Burnett, RT; Brook, J; Dann, T; Delocla, C; Philips, O; Cakmak, S; Vincent, R; Goldberg, MS; Krewski, D 

2000 

Yes 

Inhalation Toxicology
ISSN: 0895-8378
EISSN: 1091-7691 

12 

Suppl. 4 

15-39 

English 

12881885 

10.1080/08958370050164851 

WOS:000165160100004 

is part of a larger document 013204 PM2000 particulate matter and health

Alhough some consensus has emerged among the scientific and regulatory communities that the urban ambient atmospheric mix of combustion related pollutants is a determinant of population health, the relative toxicity of the chemical and physical components of this complex mixture remains unclear. Daily mortality rates and concurrent data on size-fractionated particulate mass and gaseous pollutants were obtained in eight of canada's largest cities from 1986 to 1996 inclusive in order to examine the relative toxicity of the components of the mixture of ambient air pollutants to which Canadians are exposed. Positive and statistically significant associations were observed between daily variations in both gas- and particulate-phase pollution and daily fluctuations in mortality rates. The association between air pollution and mortality could not be explained by temporal variation in either mortality rates or weather factors. Fine particulate mass (less than 2.5 "mu"m in average aerometric diameter) was a stronger predictor of mortality than coarse mass (between 2.5 and 10 "mu"m). Size-fractionated particulate mass explained 28% of the total health effect of the mixture, with the remaining effects accounted for by the gases. Forty-seven elemental concentrations were obtained for the fine and coarse fraction using nondestructive x-ray fluorescence techniques. Sulfate concentrations were obtained by ion chromatography. Sulfate ion, iron, nickel, and zinc from the fine fraction were most strongly associated with mortality. The total effect of these four component was greater than that for fine mass alone, suggesting that the characteristics of the complex chemical mixture in the fine fraction may be a better predictor of mortality than mass alone. However, the variation in the effects of the constituent of the fine fraction between cities was greater than the variation in the mass effect, implying that there are additional toxic components of fine particulate matter not examined in this study whose concentrations and effect vary between locations. One of these component, carbon, represent half the mass of fine particulate matter. We recommend that measurements of elementaland organic carbon be undertaken in Canadian urban environment to examine their potential effect on human health.