Study on the Impact of Some Selected Variables on the Dispersion of Nitrogen Oxide (NO2) using Distribution Lag Model (DLM)

Abstract

Current studies on declining air quality and its associated hazard

has shown a strong correlation between the growing rate of

urbanization and increasing number of vehicles on our roads. It is

also worthy to know that a growing numbers of pollutants emitted

from vehicular activities such as NO2 have adverse effects on

individuals as well as the atmosphere. The aim of the study is to

analyze the impact of some selected variables on the dispersion of

nitrogen dioxide NO2 using Distribution Lag Model (DLM).

Seven (7) selected locations, namely; University of Benin Main Gate,

Ekosodin junction, Agen Junction, Super D junction, Nitel junction,

Okhunmwun junction and Oluku Market junction were used for data

collection. Pollutant from vehicular emission such as dinitrogen

oxide (NO2), was monitored in the morning and evening for a period

of 35 days (7th July to 12th August 2020) with the aid of Aeroqual

multi-parameter environmental monitor (series 500) and radiation

alert meters. Other parameters of interest which were also measured

include; maximum temperature and wind speed using infra-red

thermometers and Sky master thermo anemometer (SM-28). To

ascertain the quality of the data for regression analysis, diagnostic

statistics such as autocorrelation test, heteroscedasticity, variance

inflation factor and test of reliability were done while the

distribution lag model was employed to investigate potential

collinearity among the regressor variables and to test the significant

effects of each independent variable on the dependent variable

Result of the study revealed a high concentration of NO2 around

Ugbowo maingate and Okhunmwun community and environs

especially during the peak hours (4-6pm) when the traffic load is

high. In addition, the outcome of the distribution lag model has

revealed potential collinearity between sampling distance and wind

speed; hence a reasonable conclusion was reached that; sampling

distance and wind speed did not contribute to change in the

concentration of NO2 around the study area. More also, based on

the computed p-value of 0.0340, it was concluded that; the impact of

temperature on the dispersion of NO2 is significant at the 5%

confidence interval.