Long-term trend of ambient air PM10, PM2.5, and O3 and their health effects in Tabriz city, Iran, during 2006–2017

This study was conducted to investigate the long-term temporal trends and spatial variations of ambient PM10, PM2.5 and O3 concentrations using the Moran’s I index and Mann-Kendall's test and also to evaluate their health effects in Tabriz city, between 2006 and 2017. The health impacts of air pollutants were estimated using the World Health Organization (WHO) AirQ + software updated in 2017. The results showed that the annual trend of PM concentrations was decreasing while O3 concentration was almost constant during the study period. The results indicated that in approximately 59 % and 4 % of the studied days for PM10, 48 % and 28 % for PM2.5, and 3 % and 0.3 % for O3, inhabitants of Tabriz city were exposed to the air pollutants in levels greater than the WHO AQG and National and U.S.EPA standard levels. Moreover, the highest monthly mean concentrations of PM10, PM2.5, and O3 were respectively observed in May (80.4 μg/m3), December (42.5 μg/m3), and June (78.4 μg/m3). It was estimated that attributable proportions due to long-term exposure to PM10 were between 7.9 % and 28.7 % for post neonatal infant mortality and between 20.7 % and 61.5 % for incidence of chronic bronchitis in adults. Long-term exposure to PM2.5 was attributed to about 11.8 % from all-cause, 34.6 % from ischemic heart disease, 26.7 % from stroke, 23.4 % from chronic obstructive pulmonary disease, 24.2 % from acute lower respiratory infection, and 16.5 % from lung cancer mortalities. Our study results showed that there were no effective policies and strategies to reduce Tabriz air pollution during the study period; and codification and implementation of effective control policies is necessary to improve ambient air quality of Tabriz.