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Canadian Respiratory Journal
Volume 2017, Article ID 9252069, 12 pages
Research Article

Rainfall-Associated Bronchospasm Epidemics: The Epidemiological Effects of Air Pollutants and Weather Variables

1Department of Emergency Medicine, Imam Khomeini General Hospital, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
2Air Pollution and Respiratory Diseases Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
3Department of Epidemiology and Biostatistics, Faculty of Public Health, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
4Nursing and Emergency Department, Dezful University of Medical Sciences, Dezful, Iran

Correspondence should be addressed to Arash Forouzan; moc.oohay@46898_dm

Received 29 May 2017; Revised 20 July 2017; Accepted 14 August 2017; Published 27 September 2017

Academic Editor: Isabella Annesi-Maesano

Copyright © 2017 Kambiz Masoumi et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Background. This study compares different risk factors in patients visiting a hospital during five rainfall-associated bronchospasm epidemics in Ahvaz and those visiting on other occasions. Methods. This case-control study was conducted on 5307 patients with bronchospasm admitted to the Emergency Department of Imam Khomeini Hospital in Ahvaz (Iran) from late October to December (as the epidemic) and 916 patients admitted from late January to March (as the nonepidemic) in 2011 to 2015. Results. A total of the 41.7% of the cases and 48.8% of the controls had episodes of bronchospasm, suggesting a significant difference between the two groups (). The mean concentrations of PM10, NO, NO2, and NOx pollutants (except O3) were significantly higher in the nonepidemic periods (). The adjusted analysis showed a direct significant relationship between emergency respiratory admissions and each unit of increase in NO and SO2 concentration during the epidemic periods and NO2 concentration during the nonepidemic periods. During the epidemic periods, a direct and significant relationship was also observed between respiratory admissions and each unit of increase in relative humidity and evaporation. Conclusion. The results suggest that certain pollutants and weather variables are associated with the risk of emergency respiratory admissions during epidemic periods.