Air pollution kills at least 7 million people prematurely annually. The World Health Organisation (WHO) and the Institute for Health Metric Evaluation reported this average figure.
In a WHO 2021 analysis, at least 7 million people died prematurely from air pollution in 2016. While 4.2 million died from outdoor air pollution, 3.8 million were victims of indoor air pollution. The Institute for Health Metric Evaluation placed the death figure at a minimum of 6.7 million people in 2019. From their analysis, 4.5 million died from outdoor air pollution, while 2.3 million were indoor air pollution.
Air pollution is caused by the presence of Particulate Matter (PM) in the atmosphere. PM is a mixture of coarse, fine, ultrafine solid and liquid suspended in the air that are between 2.5 micrometres to 10 micrometres, 25 to 100 times thinner than the human hair. PM2.5 refers to particles that are less than 2.5 micrometres, 100 times thinner than the human air which is why they are not visible to the human eye.
Nigeria is among the top 20 most polluted countries in the world. The country is ranked 18th among 118 countries on the Air Quality Index (AQI) in 2021. The country’s air measured in PM2.5 was 97 μg/m³ in 2021, up from 21.40 μg/m³ in 2019 when Nigeria placed 39 on the index..
The presence of PM2.5 below 12 μg/m³ is considered healthy. However, when the volume is above 35 μg/m³ during a 24-hour period, the air is considered unhealthy, and prolonged exposure to a PM2.5 above 50 μg/m³ can lead to serious health consequences, especially for people with breathing issues like asthma.
More serious health risks with PM2.5 is that it can travel deep into the respiratory tract, reaching the lungs and entering the bloodstream. Continuous exposure to excess PM2.5 is linked with increased respiratory and cardiovascular hospital admissions, emergency department visits, and deaths.
The 2021 average PM2.5 concentration of 97 μg/m³ in Nigeria is 6.8 times higher than the WHO annual air quality guideline value and Nigeria daily exceeds the required volume of PM2.5, five to seven times.
The major causes of air pollution in Nigeria are the emission from vehicles, factories burning diesel fuels, household consumption of fossil fuels, and other economic activities. These activities lead to huge carbon dioxide (CO2) emissions daily, increasing the PM2.5 level in the atmosphere.
Emissions increased between 2015 and 2019, before dropping slightly in 2020. Total emissions from fossil combustion increased from 107.8 million tonnes in 2015 to 111.1 million tonnes in 2016. It reached 112.9 million tonnes in 2017, then 130.5 million metric tonnes and 133.5 million metric tons in 2018 and 2019, respectively. However, emissions dropped to 126.9 million metric tonnes in 2020.
Average per capita of CO2 emissions by Nigerians is 0.59 tonnes annually over a 15-year period.
According to the AQI ranking, Osogbo in Osun State, was the cleanest state in the country in 2021. The city has an AQI of 75 μg/m³. Port Harcourt in Rivers State was rated the most polluted city in 2021, with an AQI of 140 μg/m³.