Assessing the Effects of Meteorological Parameters on Aerosols over Dar es Salaam, Tanzania

Abstract

The effect of meteorology on aerosols concentration in Dar es Salaam was assessed. Meteorological data (Precipitation,temperature, relative humidity and wind speed) were obtained from Tanzania Meteorological Agency during the period from 1980-2012 and the Aerosol Optical Depth (AOD) at 550nm data was sought from the Moderate Resolution Imaging Spectro-radiometer satellite(MODIS) from 2000-2012.Time series analysis based on graphical analysis of meteorological parameters and aerosols were done. Aerosols concentrations were correlated to meteorological parameters. Results showed that the highest concentrations for the aerosol optical depth were observed during the dry season and the lowest concentrations during the wet season. It is interpreted that reasons for the higher levels of the aerosols in the dry season are due to temperature inversions, soil dust dispersal and absence of rain wash-out. A negative correlation between AOD and relative humidity,temperature and rainfall, and positive correlation between AOD and windspeed was observed. The observed Aerosols concentration are affected by the variations in meteorological conditions such as precipitation, relative humidity,temperature and wind speed. Overall, the study found that the aerosols response to changes in meteorlogical parameters was somewhat reasonable identifying meteorological parameters as a driver of air quality and therefore information from this study should be used to form basis for assesing the effect of meteorological factors on aerosols.