Urban air pollution and emergency department visits for influenza

Original Article, Pol J Public Health, Vol. 132 (2022): 73-79

Mieczysław Szyszkowicz1, Nicholas de Angelis2

1 Environmental Health Science and Research Bureau, Health Canada, Ottawa, Canada
2 Biomedical Program, Department of Mechanical and Aerospace Engineering, Carleton University, Canada

DOI_disc_logo 10.2478/pjph-2022-0015

© 2022  Medical University of Lublin. This is an open access article distributed under the Creative Commons Attribution-NonComercial-No Derivs licence (http://creativecommons.org/licenses/by-nc-nd/3.0/)


Introduction. There is a large body of research which suggests that air pollutants might affect infectious diseases, their transmission, severity, and a length of recovery.
Aim. The aim of this study is to examine the relationships between ambient air pollution and emergency department (ED) visits for influenza and viral pneumonia in Toronto, Canada.
Material and Methods. The National Ambulatory Care Reporting System database was used to drawn ED visits (4 282 days). Five ambient air pollutants: carbon monoxide, nitrogen dioxide, sulphur dioxide, ozone (CO, NO2, SO2, O3, O3H8 – ozone as a maximum eight hour average, respectively), and fine particulate matter (PM2.5) were examined. In addition, the Air Quality
Health Index (AQHI; combines NO2, O3, and PM2.5) was tested. Conditional Poisson models were constructed using daily counts of ED visits. Temperature and relative humidity in the models were represented by natural splines. Air pollutants and weather factors were lagged by 0 to 14 days. The analysis was done by strata of age group, sex, and two seasons.
Results. In the period of the study, 26,200 ED visits were identified; 13,963 for females and 12,237 for males. For each air pollutant, 270 models were generated (18 strata x 15 lags). Ambient air pollution concentrations lagged by 10 and 11 days have the highest impact on ED visits, with 48 and 47 positive associations, respectively. Ozone has 181, sulphur dioxide has 104, and PM2.5 has 76 among the 417 total positive statistically significant (P-Value<0.05) associations. For all persons an increase (12.8 ppb) in ambient ozone lagged by 0, 1, and 2 days gives the following relative risks and their 95% confidence intervals 1.214 (1.135, 1.299), 1.200 (1.121, 1.284), and 1.179 (1.102, 1.263), respectively.
Conclusion. The results suggest that exposures to urban ambient air pollution affect the number of ED visits for viral respiratory illness.

Keywords: age, air pollution, case-crossover, concentration, counts, poisson, strata, urban.

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