Assessment of exhaust emissions from imported used Motor Vehicles

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Nkamba, Joseph
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University of Zambia
Zambia is tipped to be an emerging economy with current GDP (purchasing power parity) at US $ 61.79 billion (CIA World Fact Book 2015). Recorded real growth rate was at 6.5% in 2014, 6.7% in 2013 while 2012 recorded 6.8% growth rate making the country one of the fastest growing economies in sub Saharan Africa thanks to the estimated 6.33 million (2014) people that constitute Zambia’s workforce.The Transport Sector was cited to be a major source of this economic growth and specifically associated with the upgrading of 9,403 km out of a total of 40,454 km from gravel to bituminous standards and more kilometers expected to be upgraded with the various road rehabilitation projects underway.This economic growth complemented by increased access to financing (financial inclusion) has resulted in more people being able to afford at the minimum, the purchase of a used motor vehicle aged on average 8 years old. Given the ‘used’ condition coupled by old age of these motor vehicles entering Zambia’s borders in increasing numbers, citizens across the country have raised concerns on the potential environmental and safety impacts that these vehicles may have, with some advocating for a total ban of such imports. To investigate the allegations raised, a study was commissioned as part of the partial fulfillment of the award of Masters of Engineering Degree by the University of Zambia.An MGT 5 gas analyzer was used to conduct tail pipe emission testing from vehicles imported and presented for registration at Mimosa Motor Vehicle Inspection Centre in Lusaka. A total of 200 out of 116,007 imported used motor vehicles were assessed using an MGT 5 gas analyzer. All but 6 out of the 200 motor vehicles subjected to the study were passenger cars with engines ranging from 998cc to 4500 cc. with ages ranging from 1998 to 2009.From the tailpipe emission tests conducted, the exhaust contents were CO, CO2, NOX, and HC. Lambda and O2 contents were also measured to establish whether the engines in the motor vehicles presented were operating at stoichiometry or sub-stoichiometry ratios. The average emission levels found from the study of the two hundred motor vehicles were CO2 13.33 (% vol), CO (0.62 % vol), HC 204.93 ppm, O2 (1.06 % vol), λ (1.02) and NOx (25.94 ppm). The results were compared with the ZABS 560:2004 standard for imported used motor vehicles and Euro 4 (in the case of Hydrocarbons and NOx).The study concluded that these imported used motor vehicles meet both the Zambian Standard for imported used motor vehicle set by the Zambia Bureau of Standards and the Euro 4 emission standard for gasoline engine motor vehicles.
Automobile-Pollution , Automobile-Motors-Exhaust Gas-Environmental Aspects-Zambia