Journal of Chemistry and Biochemistry

Environmental Monitoring of NOX, Total Oxidants and the Implications for Photochemistry of Air Pollution over Ilorin Shed, Nigeria
Abdul Raheem A.M.O., Adekola F.A., Obioh I.B.

Abstract
The assessment of oxides of nitrogen (NOX) and total oxidants as ozone (O3) over the air shed of a typical average tropical equatorial city monitored with the aid of high volume sampler for three years is presented using three urban site classes and a control. The mean concentrations for all sites during wet season (May - October) were 3.31 ± 0.40 ppb for NOX, 21.86 ± 2.47 for O3 while the dry season (November - April) mean concentration values were 2.03 ± 0.23 ppb for NOx and 32.44 ± 5.13 for O3. Mean value at the control site was an order of magnitude lower than the urban sites during the two seasons except concentration of O3 higher during the dry season. Traffic density and trace gas concentrations showed good correlation of 0.98 (P<0.05). NOx was confirmed to be a strong precursor for O3 formation. The influence of Harmattan dust in impeding the photochemistry of O3 formation from November to January (NDJ) months was observed. The overall concentration levels of NOx and O3 for the air shed are 2.67 ± 0.32 and 27.15 ± 3.8 respectively, within the limit of United States Environmental Protection Agency (USEPA) guidelines for air quality standards.

Full Text: PDF     DOI: 10.15640/jcb.v7n1a1