A GIS Based Approach to Back Trajectory Analysis and Mass Concentration & Dispositions of Aerosols in Nairobi, Kenya

The origins and pathways of atmospheric aerosols in Kenya are examined in Nairobi for the three years (2015-2017) using HYSPLIT model and meteorological data. Aerosol concentrations in Kenya depended on the frequency of the air mass from the northeastern Asian Continent and southeastern Madagascar Island. There was a direct correlation of more pollutants during dry and hot seasons (JJA) of the year. To study the reasons for the seasonal variations, the origins of the air mass flowing to Nairobi were analyzed by backward air mass trajectory analysis. Monthly variations revealed that aerosols are transported from different directions due to variation of winds flowing and peak values were during July because of the increased emissions due to higher temperature and stronger solar radiation during heating, while the lowest value found in April was probably due to rain wash.