Measurement of fine particle concentrations and estimation of air quality index (AQI) over northeast Douala, Cameroon

Abstract

The paucity of data regarding air quality monitoring and pollutant emissions from various sources in the city of Douala, allowed us to initiate a measuring campaign at the main road entrance of the university campus. Using the OC 300 Laser Dust Particle, nes particles concentrations are monitored during one week from Monday to Sunday. The instrument used detects four (04) different sizes of particles: PM 10 , PM 5 , PM 2.5 , and PM 1 . The daily average concentrations measured ranged from 9.47 ± 0.26 to 50.14 ± 2.42 µg.m − 3 for PM 1.0 ; 13.13 ± 0.38 to 86.65 ± 3.96 µg.m − 3 for PM 2.5 ; 13.60 ± 0.40 to 100.56 ± 4.20 µg.m − 3 for PM 5 and 14.52 ± 0.42 to 114.59 ± 4.60 µg.m − 3 for PM 10 . Exceptions made from PM 5 and PM 1.0 which were not in relation to the WHO (World Health Organization) guideline values, the level of PM 10 and PM 2.5 are higher than the WHO standards. The air quality index (AQI) is between very poor and poor during this measurement campaign, indicating that residents of the study region are highly exposed.Through the use of correlation studies, it has been demonstrated that the predominant source of ne particles in the studied region is vehicular activity. As a result, tra c density is the most signi cant factor causing the different air pollution levels seen in the tested areas.