Onitsha, an Anambra State city with over 350,000 inhabitants, was ranked as the world’s worst city in terms of air quality. The WHO measured air quality by examining the annual mean concentration of particulate matter (PM10) in nearly 3000 cities across the world with populations of at least 100,000. Onitsha’s average annual PM10 was recorded to be 594, which is nearly 30 times greater than the WHO-recommended annual PM10 level of 20.
According to the report, low-income cities tend to have the highest levels of air pollution and are more vulnerable to the negative effects of air pollution than wealthier cities. In low- and middle-income countries, 98 percent of cities with at least 100,000 inhabitants do not meet WHO air quality standards. However, that percentage is only 56 in high-income countries.
Poor air quality poses serious risks to public health. The report notes that as air quality declines, the risk of stroke, heart disease, lung cancer, and chronic and acute respiratory diseases increases for inhabitants of the affected cities.
“Air pollution is a major cause of disease and death,” says Dr. Flavia Bustreo, WHO Assistant-Director General of Family, Women and Children’s Health. “When dirty air blankets our cities the most vulnerable urban populations—the youngest, oldest and poorest—are the most impacted.”
According to the WHO, over 3 million people die prematurely every year due to high levels of air pollution, and despite improvements in air quality in some cities, global air pollution levels have increased by 8 percent since 2013.
“Urban air pollution continues to rise at an alarming rate, wreaking havoc on human health,” says Dr. Maria Neira, WHO Director of the Department of Public Health, Environmental and Social Determinants of Health.
The report notes that reducing the level of air pollution requires action by urban and national governments. The WHO calls on policymakers to reduce industrial smokestack emissions, promote the use of renewable power sources, and prioritize rapid transit, walking, and cycling networks in cities most affected by air pollution.
“It is crucial for city and national governments to make urban air quality a health and development priority,” says WHO’s Dr. Carlos Dora.
“When air quality improves, health costs from air pollution-related diseases shrink, worker productivity expands and life expectancy grows. Reducing air pollution also brings an added climate bonus, which can become a part of countries’ commitments to the climate treaty.”