Journal of Environment Pollution and Human Health, 2016, Vol. 4, No. 4, 83-90 Available online at http://pubs.sciepub.com/jephh/4/4/2 ©Science and Education Publishing DOI:10.12691/jephh-4-4-2 Spatial Variability of Ambient Air Pollution Concentration in Dar es Salaam Robert M. Njee 1,2,* , Kees Meliefste 3 , Hamisi M. Malebo 2 , Gerard Hoek 3 1 Preventive Health Department, Ministry of Health and Community Development Gender Elderly and Children, P.O. Box 9083, Dar es Salaam, Tanzania 2 Department of Traditional Medicine, National Institute for Medical Research, P.O. Box 9653, Dar es Salaam, Tanzania 3 Institute for Risk Assessment Sciences, Utrecht University, P.O. Box 80178, 3508 TD Utrecht, the Netherlands *Corresponding author: robertmussa@gmail.com Abstract Epidemiological evidence shows health effects of ambient air pollutants. Such effects have been evaluated in different regions of the world but scarcity of pollution measurements in Sub Saharan Africa (SSA) limits understanding of pollution levels and related health risks. Our aim was to assess spatial variability of concentrations of key air pollutants in a major African city. Particles smaller than 2.5 and 10 μm (PM 2.5 and PM 10 ), the absorbance of PM 2.5, and NO 2 / NO x were measured in dry season at locations close to identified pollution sources. Higher PM 10 , PM 2.5 and soot concentrations were measured compared to typical European concentrations. NO 2 concentrations were moderate. PM 10 ranged from 86 μg/m 3 at the urban background to 248μg/m 3 at the landfill site, likely related to unpaved roads. PM 2.5. varied from 27μg/m 3 at the harbor site to 49μg/m 3 at the traffic site. Measured PM 2.5 concentrations were several times higher than the global 2005 modelled values based upon satellite and chemical transport modelling. PM 10 and PM 2.5 concentrations were 1.8 and 1.6 times higher at the traffic site compared to the urban background, a larger contrast than in most western studies. Suburban PM 10 , PM 2.5 and soot absorbance concentrations were higher than at central urban location. The high soot concentrations document that combustion sources including motorized traffic contribute to the high PM concentrations. Average NO 2 concentrations ranged from 8 μg/m 3 to 109 μg/m 3 . Emissions from road traffic vehicles were shown to have the strongest influence on all ambient pollutants, although emissions levels where roads were unpaved were associated with elevated levels of particulates. Spatial variability of particulate matter air pollution was larger and showed different patterns than reported in European / North American study areas. Ambient pollution monitoring with mitigation measures targeting road traffic emissions are necessary in averting negative health consequences of ambient pollution in SSA cities. Keywords: ambient air pollution, concentration, variability, Africa. Cite This Article: Robert M. Njee, Kees Meliefste, Hamisi M. Malebo, and Gerard Hoek, “Spatial Variability of Ambient Air Pollution Concentration in Dar es Salaam.” Journal of Environment Pollution and Human Health, vol. 4, no. 4 (2016): 83-90. doi: 10.12691/jephh-4-4-2. 1. Introduction Ambient air pollution is an established risk factor for diseases affecting respiratory system. Evidence is mounting on the role of air pollution in exacerbating other disease endpoints particularly lung cancer, cardiovascular diseases, and on its negative effects to the health of children exposed early in life [6,11,17]. Recognition of the growing problems of ambient air pollution and its negative implication to public health led to adoption of control measures including emission standards for factories and automobiles in industrialized countries [1,8]. Application of pollution controls are now reported to have significantly reduced pollution levels in most of Europe and North American cities [15,24]. Contrariwise, air pollution levels have been on the increase in most developing countries [15]. Recent analysis of global data on ambient air pollution suggests an increasing trend of urban ambient pollution levels in cities of developing countries with highest increase recorded for Africa region [35]. Ambient particulate air pollution is now estimated to contribute 3.7% of premature deaths and 3.1% of global Disability Adjusted Life Years (DALY). Africa contribute 5% of the global burden due ambient air pollution [34]. Information on levels of ambient air pollution for Sub Saharan Africa (SSA) is still scanty [4,16,26,29,32]. Air pollution data for most cities is obtained from small discrete monitoring programs rather than established networks, leading to uncertainty about particulate levels. Uncertainty in exposure further limits estimation of related public health impact [32]. Paucity of pollution data necessitates the use of regional estimates and isolated monitoring data in the determination of attributable disease burden for SSA [2,3,27,33]. The available data is largely limited in precision and ability to reflect on spatial variability within relatively small geographical areas such