Investigating the drivers of air pollution and personal exposure within informal settlements in Nairobi, Kenya.

A recent study in Nairobi, Kenya has shown that urban background sites frequently exceed the 24-hour limit value of 25 µg m-3 for particulate matter of 2.5 µm or less (PM2.5) set by the World Health Organisation. Previous studies in Nairobi have not investigated the composition of PM or the role that reactive nitrogen gases may have in urban air pollution, in particular nitrogen dioxide (NO2) and ammonia (NH3). It is estimated 60% of the Nairobi’s population now live within informal settlements. Residents of informal settlements are thought to be particularly exposed to air pollution, where potential sources include dust, human and animal waste, cooking, burning of waste, transport and local industries. Here we present a pilot study to investigate the feasibility of using a combination of low cost static air quality monitoring and personal exposure methodologies to gain knowledge on personal and community exposure within an informal settlement. Background monitoring is being carried out at two stations using a Denuder for Long-Term Atmospheric sampling (DELTA) which measures both reactive trace gases (NH3, HNO3 and SO2) and their counterpart aerosols (NH4+, NO3-, SO42-). Within the informal settlement, static monitoring by NO2 and NH3 passive samplers and mobile personal exposure studies (Dylos) are achieved using a citizen science approach based on the methodologies of Steinle et al. (2015) and West et al. (in prep). The initial results from this study including a discussion on the applicability of low cost approaches for studying air quality in Sub-Saharan Africa will be presented.