Assessment of population exposure to climate change-induced exceedances of health-based air pollution thresholds in some urban areas in Kenya.

Abstract

Air quality is worsening in the rapidly growing metropolises of sub-Saharan Africa, including those in Kenya. In parallel, there is increasing evidence that air pollution is affecting health. Furthermore, since air quality is strongly reliant on weather, it is sensitive to climate change. While health effects can occur in the absence of climate change, their incidence, intensity and distribution will be influenced by the alteration in the weather patterns. This study sought to assess the population exposure to climate change-induced exceedances of health-based air pollutants over Kenya. In order to achieve this, climate projections were obtained from CORDEX Regional Climate Model driven by a General Circulation Model under forcing from Representative Concentration Pathway RCP-4.5 and RCP-8.5 greenhouse gases emission scenarios. Daily weather variables (rainfall, minimum and maximum temperature, relative humidity and wind speed) and satellite column measurements of air pollutants (ozone, nitrogen dioxide, sulphur dioxide, particulate matter, formaldehyde and carbon monoxide) were obtained over two time slices; 2005-2015 as baseline, and 2035-2045 as future. The weather variables were obtained from the Kenya Meteorological Department. Respiratory-related morbidity and mortality data from March 2015 to March 2016 were obtained from Kenyatta National Hospital. Socioeconomic and environmental risk factors for severe respiratory disease prevalence were collected through the administration of questionnaire in a survey carried in Nairobi, Mombasa and Uasin Gishu counties between 28th May 2016 and 3rd June 2016.