Time Resolved Variations of PM0.5, PM 2.5 and PM5 in Number from some Selected Areas (Savar, Gazipur and Narayanganj) of Dhaka Division

The study was conducted to find out the time resolve variations of particulate matters (PM0.5, PM2.5 and PM5) in some selected places of Savar, Gazipur and Narayanganj of Dhaka division using Video Particle Counter 300 (VPC 300). We found the distribution pattern of atmospheric particles in all the area studied as 0.5 µm>2.5 µm>5 µm. In this study, we observed that PM0.5, PM2.5, and PM5 particles have been increased from morning to noon and evening, indicating their sources are anthropogenic. During the morning, PM0.5 particle in number ranged from 176269-268219 N (avg. 23640730572 N). However, at noon particle having size of 0.5 µm in number ranged from 290785-412355 N (avg. 33652543905 N) and at evening, particle of same size ranged from 390968 N-694691 N, (avg. 49200385049 N). Interestingly, PM0.5 size has been increased in the study area by ~1.4 times of same size from morning to noon and by ~1.5 times than that of noon. Such increment of PM0.5 from morning to noon and evening may signify their sources in the study areas are associated with anthropogenic activities like vehicles, industry and construction activities. Moreover, in the morning time PM5 loads in number has been decreased by 4.5 times than those of PM2.5, indicating atmospheric dry deposition of larger size particles from the study area.