The effects on human health due to poor air quality mainly involve the respiratory system and the cardiovascular system. Individual reactions to air pollutants depend on the type of pollutant a person is exposed to, the degree of exposure, the individual's state of health and genetics.
The study Impact of air pollution on stunting among children in Africa, published on the Environmental health: a global access science source, explained: "Undernutrition is a global public health crisis, causing nearly half of deaths for children under age 5 years.
Little is known regarding the impact of air pollution in-utero and early childhood on health outcomes related to undernutrition. The aim of our study is to evaluate the association of prenatal and early-life exposure to PM2.5 and child malnutrition as captured by the height-for-age z-score (HAZ), and stunting in 32 countries in Africa.We also evaluated critical windows of susceptibility during pregnancy to each environmental risk.
We linked nationally representative anthropometric data from 58 Demographic and Health Surveys with the average in-utero PM2.5 concentrations derived from satellite imagery. We then estimated associations between PM2.5 and stunting and HAZ after controlling for child, mother and household factors, and trends in time and seasonality.
We observed lower HAZ and increased stunting with higher in-utero PM2.5 exposure, with statistically significant associations observed for stunting (OR: 1.016 (95% CI: 1.002, 1.030), for a 10 μg/m3 increase). The observed associations were robust to various model specifications.
Wald tests revealed that, wealth quintile and urban/rural were not significant effect modifiers of these associations. When evaluating associations between trimester-specific PM2.5 levels, we observed that associations between PM2.5 and stunting was the largest.
This is one of the first studies for the African continent to investigate in-utero and early-life exposure to PM2.5 is an important marker of childhood undernutrition. Our results highlight that PM2.5 concentrations need to be urgently mitigated to help address undernutrition in children on the continent." Indoor air pollution and poor urban air quality are listed as two of the world's worst toxic pollution problems in the 2008 report.
Outdoor air pollution causes 2.1 to 4.21 million dead every year. Collectively, air pollution causes the deaths of approximately 7 million people worldwide each year and is the largest single environmental health risk in the world.