The paper employs a nonlinear autoregressive distributed lag (NARDL) approach to cointegration in order to examine the interactions among air pollution, economic growth and healthcare expenditure in Nigeria by using time series data from 1990 to 2022. The results show the long run impact of air pollution (Carbon dioxide emission) on health expenditure to be positive and statistically significant at 1%. Also, it reveals the existence of significant nonlinear effect of economic growth on healthcare expenditure. Specifically, 1 percent point increase in gross national income leads to -0.383919 percent point decrease in total health expenditure as a share of Gross Domestic Product.1 percent point decrease in gross national income leads to 571.143839 percent point decrease in total health expenditure as a share of GDP. As such, Nigerian government should increase public health expenditure so that the health of the individuals in the society will be adequately taken care of and mortality rate reduced. Similarly, Nigerian government alongside development actors should institute low-carbon mechanisms like green infrastructure and renewable energy systems that reduce energy consumption and carbon dioxide emissions.