Magnitude and variation of traffic air pollution as measured by CO in the City of Addis Ababa, Ethiopia

Abstract

Background: Air pollution level in Addis Ababa is presumed to be high due to the prevalence of old vehicles and substandard road infrastructures. This study assessed CO concentration as a measure of traffic air pollution. Materials and methods: a total of 80 road side and 24 on-road daily traffic air samples during wet and dry seasons of 2007 and 2008, respectively, were taken using CO data logger. A structured checklist was used to document related data. Downloaded data from the CO sampler was used to generate summary statistics and data presentations. Data quality of CO measurement was ensured using calibration checks. Results: The mean for 15 minutes CO concentration was 2.1 ppm (GM=1.3) and 2.8 ppm (GM=2.2) for wet and dry seasons, respectively. The concentrations from season to season varied statistically. The CO temporal and spatial profiles among the two seasons were similar. The overall mean on-road CO concentration was 5.4 ppm (GM=5.3). Fifteen percent of roadside samples and all on-road samples exhibited more than 50% of the 8-hr CO WHO guideline.. Daily CO maxima were observed in early mornings and late afternoons. Conclusions: The consistency in spatial and temporal profiles and the variation on both on-road and road side traffic lines imply that vehicles are the main source of traffic air pollution. There is a concern that the CO 8-hr World Health Organization guideline might be exceeded in future. [Ethiop.

Ambient Air Pollution Status of Addis Ababa City; The Case of Selected Roadside

“…All the sites (SS16, SS40, SS3, SS41, SS33, SS39, SS38, SS26 and SS35) with high CO concentration (mean ± SD) are sites located in the high congestion traffic zones of Addis Ababa. The finding of this study is higher than the value reported (2.8 and 2.1 ppm in dry and wet seasons respectively) by [3] which was studied in the same city (Addis Ababa) and lower than the one reported by [16]. The higher concentration of CO recorded in this research work was may be due to the indirectly increased vehicle congestion in the city.…”

“…The daily (hourly) maximum CO concentration recorded during the study period was 18 ppm for SS14 and SS3 sampling sites on rushing hours of the day on 9:00 am and 5:00 pm respectively [ Figure 4]. The high CO concentration in the early morning and late afternoon was due to the congested vehicular staging and stagnation of temperature in the city [3,16]. The low concentration of CO at mid-day was because of the photochemical reaction taking place by sunlight in the presence of hydrocarbons as CO is converted to carbon dioxide [3].…”

“…However, 3.7 and 4.3 million are only due to Ambient Air Pollution (AAP) and Indoor Air Pollution (IAP) respectively [1,2]. Population growth, limited emission control technology, substantial scale of urbanization, increased demand of transportation service, land use without planning, low quality fuels, age of vehicles, increased road congestion and lack of effective transport are among the factors contributing to enhanced vehicular urban air pollution [2][3][4][5][6]. The combined effects of urban air pollution factors create adverse air pollution by forming traffic air pollution.…”

“…Urban environment of both developed and developing countries like Ethiopia, vehicular emission pollution are a major source of emissions of ultrafine particles in ambient/outdoor air both at national and local level [3,4,5,9,10]. Ninety (90%) urban air pollution is rapidly growing and expanding in cities like Addis Ababa is due to motor vehicle emission.…”

Variation in Parameters of Ambient Air Quality in National Capital Territory (NCT) of Delhi (India)

“…Private vehicles account for 30% of the total demand for transportation, while the rest of the demand is met largely by auto-rickshaws and taxis. Reddy and Venkataraman [7] and Abera et al [8] note that the pollutants like CO and NO x emanate from automobile exhausts, whereas use of coal based fuels causes heavy emissions of SO 2 . Murphy (2008) et al [2] and Rosibeto et al [9] find that the levels of O 3 , NO x and particulate matter are an issue of concern in the urban environment.…”