Spatial variation of volatile organic compounds and carbon monoxide in Blantyre City, Malawi

Abstract

This study assessed variations of ambient volatile organic compounds and carbon monoxide (CO) levels in Blantyre City, Malawi. Volatile organic compounds and carbon monoxide measurement was done using the Multi-Gas Monitor between August and December, 2010. Rapid urbanization and lack of standard enforcement on air pollution as well as lack of data on pollutant levels in the city prompted this study. The study focused on methane volatile organic compounds and non-methane volatile compounds besides carbon monoxide. Results of the analysis showed that non-methane volatile compound levels were highest at public bus terminuses with 12.40 ± 0.83 ppm, and lowest for industrial locations (2.16 ± 0.09 ppm). However, all points registered zero (0.00) ppm for methane volatile organic compounds. Similarly, mean levels of carbon monoxide were highest at public bus terminuses with 10.92 ± 0.74 ppm, and lowest for industrial locations (1.11 ± 0.13 ppm). With the exception of Ginnery Corner, all the sampling points had levels of both parameters within the air quality standards. The study revealed a spatial and diurnal variation of the pollutants in all sampling points. It further revealed that the sources of these pollutants are diverse with vehicular emissions being the main  source for Masauko Chipembere highway.

Key words: Air pollution, ambient, permissible limit, urban, vehicular emission.