Open AccessTemporal Variations in Air Pollution at Two Roundabouts in the City of Cotonou (Benin)
Author(s) -
L M Karine Codjo-Seig,
Vincentia M C Houssou,
Philippe Kossolou,
Ghislain Emmanuel Sopoh,
Martin Pépin Aïna
Publication year - 2021
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.579
H-Index - 13
ISSN - 2279-9028
DOI - 10.4081/jphr.2021.2193
Subject(s) - nitrogen dioxide , ozone , air pollution , environmental science , pollution , environmental chemistry , benin city , environmental engineering , meteorology , geography , chemistry , ecology , medicine , biology , general surgery , organic chemistry , teaching hospital
Background Air pollution has caused health and environmental problems around the world. In this study we analysed the temporal evolution of air pollution in Cotonou regarding the standards of Benin and of World Health Organization (WHO).Design and methods Solar-powered electrochemical sensors (CO: carbon monoxide, SO 2 : sulphur dioxide, and O 3 /NO 2 : ozone/nitrogen dioxide) and photoionization detectors (for NMVOC: nonmethane volatile organic compounds) were permanently installed and monitored from June 2019 to March 2020 at Akpakpa PK3 (A) and Vèdokô Cica-Toyota (B) roundabouts.Results CO and SO 2 concentrations at both roundabouts were significantly higher on weekends than on weekdays. The concentrations of NMVOC and O 3 / NO 2 on Sunday differed considerably from the other days of the week at A and B, respectively. There was a positive linear correlation between the concentrations of CO and SO 2 , O 3 / NO 2 and SO 2 , and CO O 3 / NO 2 to B, and only between CO and O 3 / NO 2 , in A. At the two sites, the average of SO 2 concentrations (in μg/m 3 ) were higher than the WHO standard (500) for an exposure of 10 minutes (2258 A and 2143 B) and the Benin standard (1300) for 1 hour exposure (2181 in A and 2092 in B).Conclusion Air pollution varies in hours and days in Cotonou. Standards are respected, except for SO 2 . Particular attention should be paid to the concentrations and the possible sources of gas. More sophisticated monitoring system should be put in place.