Assessment of Air Pollution and Prevalence Levels of Respiratory Diseases in Mukuru Informal Settlement in Nairobi City, Kenya

Abstract

Air pollution is one of the major environmental issues globally and is more pronounced in Sub-Saharan Africa (SSA). It is associated with adverse health effects, including respiratory diseases that have led to high morbidity and mortality rates. The urban population in SSA is further concentrated in the slums and more often it uses highly polluting fuels for cooking. This has caused the release of elevated levels of pollutants into the environment. The study was aimed at determining households and ambient PM2.5, and CO levels in densely populated Mukuru slum and control site during the rainy and dry seasons The meteorological conditions that prevailed and prevalence levels of respiratory diseases in the communities were also evaluated. Outdoor and indoor PM2.5 levels were collected for 24 hours for three consecutive days at each site using Harvard impactors with the preconditioned polytetrafluoroethylene filters. They were then analyzed using the gravimetric technique. Ambient and household CO levels were also sampled at each site using a portable lascar easy CO data logger. The ambient mean levels of PM2.5 and CO were compared with those of the WHO air quality guidelines. During the same period, the incidences of respiratory diseases in the communities were obtained from the community health facilities. The PM2.5 levels (μg/m3) in the households in the Mukuru slum ranged from 8 to 151 and 50 to 274, with overall means of 61.4±43.6 and 137±56.9 during the dry and rainy seasons, respectively. The control site had relatively lower indoor PM2.5 with mean levels (μg/m3) of 19±9.2 and 19 ± 7.6 ranging from 13 to 30 and 12 to 27 during the dry and rainy seasons, respectively. On the other hand, the outdoor PM2.5 levels (μg/m3) ranged from 13 to 77 and 20 to 64 with overall means of 38.85±17.7 and 37±14.9 during the same period. In all cases, the mean ambient PM2.5 levels at each site exceeded the WHO air quality guideline of 15 ug/m3 over the 24-hour period. The household CO levels in the slums ranged from 0.45 to 13.42 ppm and 0.95 to 32.47 ppm with means of 4.48±3.50 ppm and 12.22±10.52 ppm during the dry and the rainy season, respectively. The CO levels (ppm) in the ambient air ranged from 0.04 to 1.50 and 0.001 to 1.02 with means of 0.35±0.29 ppm and 0.46±0.35 ppm during the same period. The ambient CO levels were all within the 24-hr WHO set limits of 3.5 ppm. On the contrary, the control site had both household and ambient CO levels that were less than 0.001 ppm for both seasons except for the latter during the rainy season. The prevalence levels of respiratory diseases from the Mukuru communities were higher than the control. It ranged from 36.9 to 46.7% and 30.6 to 43.8% whereas for the control health facility had 25.4 and 32.2% during the dry and rainy seasons, respectively. The study recommends continuous monitoring of air pollution and environmental health -driven policies to reduce the levels of PM2.5 and household CO.