Trends of Particulate Matter PM2.5 and PM10 Concentrations in Dar Es Salaam City Between 2021 and 2022 as measured by Low cost Sensors.

The ambient air quality of Dar es Salaam city has been monitored using 14 low cost PurpleAir PA-II sensors deployed May 2021 to measure particulate matter (PM2.5 and PM10). Daily average of PM2.5 and PM10 concentration recorded at sites across Dares Salaam city between May 2021 and February 2022, has been analyzed. Higher PM2.5 and PM10 concentration values were observed at Pugu Dampo (77.26 g/m3 and 90.89 g/m3 g/m3, respectively) and DMDP Magomeni (77.25 g/m3 and 94g/m3 respectively) as compared to other stations. While Pugu Dampo is an open municipal waste dumpsite, DMDP Magomeni station is located near traffic congestion dominated junction part of the city. Comparing the observed daily mean values of PM2.5 and PM10 across the stations for the study period, the higher value was from Pugu Dampo (37.94 g/m3) and Vingunguti Primary school (47.49 g/m3) respectively. Vingunguti Primary schools, is located in industrial area part of the Ilala District and also is near the major traffic roads and not far from the international airport. Overall, it has been observed that most observed daily mean and maximum values of PM2.5 and PM10 from sensor stations near busy traffic roads, at the municipal waste dumpsite and in industrial areas exceeds the recommended WHO values. Also, the analyzed data, reveals that the pollution from particulate matter varies greatly across the municipal stations and with time of the day.