Examining localized patterns of outdoor and indoor particulate matter in the district of Al-Koura : a spatial and statistical analysis

Abstract

Lebanon, a small Asian country located along the eastern shore of the Mediteranean Sea, is ranked amongst the major air pollution hotspots in the Middle East region, and is considered as an important investigating area for air quality assessment. In spite of the presence of major sources of pollutants emission in Northern Lebanon including cement factories and quarries, phosphate fertilizer industry, transport activities, and other human activities, knowledge about air pollution levels in this region remains sparse and exiguous. Within the scope of this study, a population based questionnaire was conducted in the district of Koura to determine the irritation and annoyance levels of air pollution among citizens. Moreover, ambient levels of particulate matter (PM) were sampled daily at the University of Balamand (UOB) during three sampling campaigns covering the time period from 11 December 2018 to 27 January 2019. Indoor levels of PM were also monitored inside schools like Kfarhazir official School, Bichmizzine High School, and Kfarhata Official High School, and houses located in Kfarhazir, Fih, Anfeh, and Kaftoun. The population based survey showed that respondents perception of air pollution was strongly correlated with many socio-demographic factors. For instance, respondents residing in the vicinity of cement factories and quarries, located respectively in the regions of Kefraya and Kfarhazir, expressed pronounced annoyance levels and health problems, while those living in rural areas like Kaftoun reported good air quality and health conditions. Age and gender, as well, are found to influence the perception of air pollution. Respondents above the age of 35 are more aware and conscious about the adverse effects of air pollution. Women complained more about air pollution, and perceived air quality poorer than it actually is. To sum up, the questionnaire showed high annoyance, irritation, and adverse health effects arising from air pollution, and confirmed the need to conduct such a study in the district of Koura. Average mass concentration of PM10 at UOB was 35.23μg/m3 during the first sampling campaign, and that of PM2.5 was 20.5μg/m3 and 26.09μg/m3 during the second and third campaigns respectively. Daily mass concentration of PM exhibited significant variations as a function of meteorological conditions. Wind direction was taken into consideration, to determine the sources of emissions of PM that are relevant to influence the site. Mass concentrations of PM2.5 measured in the presence of south to southwesterly (SSW) wind direction were significantly higher than those measured in the presence of easterly to southeasterly (ESE) wind direction, and this was justified through One-way Analysis of Variance (ANOVA) statistical test which showed that SSW winds were more correlated with the mean of concentration. Chekka and Selaata located in a south westerly position relative to UOB, and housing heavy industries like cement factories and quarries, phosphate fertilizer industry, and paper factories are the most significant sources of PM2.5 emissions that affect the site. Owing to their small travel distance, long range transport of PM10 from distant regions tends to be chaotic. Hence, the sources of PM10 emissions influencing the site were due to activities generated within the university including tire and brake ware, road surface abrasion, crustal dust, and primary biogenic aerosols particles (PBAP). PM monitored in houses indoor, showed that the average mass concentration recorded in Kfarhazir was 16.1μg/m3 for PM2.5, and 32μg/m3 for PM10. Particles in this site originated mainly from infiltration, and were due to the geographical location of the house that is situated along a busy arterial road and in proximity to quarries. The lowest PM2.5 and PM10 concentrations measured in Kaftoun were 11.41μg/m3 21.9μg/m3 respectively.