Analysis of air quality monitoring data in the urban-industrial region of Chekka/Selaata

Abstract

Air pollution is becoming a worldwide major threat for human health resulting in millions of deaths per year. Monitoring air quality is therefore crucial to find solutions that limit air pollution and accordingly decreasing the exposure of people to air pollutants. In Lebanon, most of the air quality research revolved around the capital Beirut, while few studies dealt with industrial pollution. Chekka and Selaata cities, which are considered as industrialized areas, are zones that exhibit emissions of large concentrations of pollutants leading to serious environmental and health impacts at downwind populations. There are few studies that attempted to understand the air quality around industrial regions in Lebanon, this is why this work encloses an analysis of air quality monitoring data and meteorological data collected by the Ministry of Environment in the urban-industrial region of Chekka/Selaata, namely Fiaa, Kfarhazir, Hamat and Qelhat, from June 2017 till July 2019. The results showed that in 2017, 2018 and 2019 all the pollutants exceeded the recommended limit values of the WHO at Fiaa except for SO2 in 2019. In Kfarhazir, Hamat and Qelhat, PM was in exceedance in 2017 and 2018. In 2019, PM10 and PM2.5 exceeded at Kfarhazir, but were below the limit values at Qelhat. The time variation analysis showed that NO and NO2 have similar trends, NO2 and O3 showed opposing trends. PM10 was found to be related to PM2.5 at all sites, sometimes this relationship is disturbed, showing higher levels of PM10 probably from quarrying activities. Polar plot analysis showed that in Fiaa, the levels of NO, NO2, SO2 and O3 were possibly related to the Chekka/Selaata industrial complex (cement factories and chemical fertilizer factory). In Kfarhazir, Lafarge-Holcim grey cement stack in Chekka and possible agricultural and/or residential emissions could be the major contributors of high PM levels. In Hamat, major PM contributions were found possibly generated from the Lebanese Chemicals Company and the Mseilha dam construction project. Whereas in Qelhat, the possible contributions in PM loads may have been related to the food manufacturing plant (KARIM), a Sand/Pavement processing plant, in addition to agricultural and/or residential activities. The air mass back-trajectory analysis helped to narrow down the sources contributing to the air pollution to local sources in most cases of pollution episodes the results obtained from the polar plots about the industrial, long-range transport and other possible sources of pollution emission. The result of this study shows that the contribution from the Chekka/Selaata industrial complex wind sector, and sometime from other possible distant sources, led to high levels of air pollution in Fiaa, Kfarhazir, Hamat and Qelhat. Therefore, a more complex chemical analysis of metals, soluble ions and organic compounds in PM samples was suggested to define the individual emission’s contribution in the region. In addition, this study recommended the use of the findings to compare with clinical data to uncover the possible impacts of these pollutants on the local community in the study area.