THE IMPACT OF AIR POLLUTION ON MORTALITY RATES IN NIGERIA: A STATISTICAL PERSPECTIVE.

Abstract

This study examined the association between air pollution indicators and mortality rates in
Nigeria over the period 2000 - 2024, the data obtained were mainly secondary data sourced from
the World Health Organization’s Global Health Observatory and National Bureau of Statistics.
In this paper, the independent variables are: Particulate matter concentrations (PM 2.5 and PM 10 ),
Nitrogen dioxide (NO 2 ) concentrations, Sulfur dioxide (SO 2 ) concentrations and Ozone (O 3 )
concentrations where the response variable is Mortality rate. The study employed Multiple
regression and correlation to investigate the influence of five air pollutants (PM 2.5 , PM 10 , NO 2 ,
SO 2 , and O 3 ) on mortality rates. From the regression models formed through Multiple Regression
Analysis; Y = 16.109 - 0.050(PM2.5) + 0.028(PM10) - 0.083(NO 2 ) - 0.031(SO 2 ) + 0.028(O 3 ).
The negative coefficients observed for PM 2.5 , NO₂, and SO₂ suggest that their annual mean
concentrations were inversely related to mortality rates, whereas PM 10 and O₃ exhibited positive
associations. The opposing signs for PM 2.5 and PM 10 , despite PM 2.5 being a component of PM 10 ,
further suggest model misspecification or omitted variable bias rather than divergent health
effects. Similarly, the positive association observed for O₃ may be attributable to seasonal
confounding with temperature or other unmeasured covariates. These results diverge from
established epidemiological evidence and are best interpreted as exploratory, hypothesis-
generating associations that likely reflect residual confounding and shared temporal patterns
rather than causal exposure effects. Furthermore, diagnostic tests for multicollinearity,
heteroskedasticity, and autocorrelation confirmed that the dataset was free from these statistical
issues.