Characteristics Of Ambient PM2.5 In Relation To Meteorological Parameters In Dhaka City, Bangladesh

Abstract

Air Pollution is one of the foremost environmental problem in Dhaka city. This study aims to assess the characteristics of Particulate Matter (PM2.5- diameter is less than 2.5 micrometers) in relation with meteorological parameters in Dhaka city. Data were gathered from the Air Now Department of State (Air Now DoS) collected through PM2.5 monitor (beta attenuation monitor BAM-1020) installed at the U.S. Embassy in Dhaka. The maximum monthly average concentration was found 203±69.906 µg/m3 in the month of January while minimum average concentration was found 30±16.040 µg/m3 in July in the year of 2018. This study also observed that 54% of the total hours AQI was “Unhealthy” while only 2% was “Good” and most of the time (77%) the condition was beyond livable. The annual concentration of PM2.5 was found 99.36±79 µg/m3 in 2018 which exceeds the NAAQS of Bangladesh and WHO standard. It is revealed from the study that, significant strong negative correlation exists between PM2.5 and meteorological parameters (Temperature, Humidity and Rainfall) individually and as a set these three parameters account for a significant 92.2% variation in PM2.5 concentration whereas singly temperature can attribute significant unique variance to the concentration. Hence winter season is found as most polluted on the basis of PM2.5 concentration compared to other. Furthermore, the concentration of PM2.5 is found high night and morning shift may be due to movement of Long-route buses and any kind of heavy-duty diesel trucks along with studied meteorological parameters.