Air pollution levels are unsafe in nearly all cities in developing countries, according to new data from the World Health Organization, which shows that more than 80 percent of people living in urban areas around the world are exposed to high levels of air pollution. It is a problem that kills more than 3 million people prematurely each year and takes a heavy toll on the world’s poorest.
The database tracking some 3,000 cities in 103 countries shows that the air quality gap is global. Pollutants that affect the lungs and cardiovascular system, including sulfate, nitrates and black carbon are above limits set by the World Health Organization in 56 percent of cities located in high-income countries. And many of those countries saw pollution levels decline over the past five years.
On the other hand, low- and middle-income countries are nearly completely made up of cities with too much air pollution. Some 98 percent of cities in those countries have air pollution levels exceeding the WHO limit. Further, many regions are getting worse as pollution is increasing in recent years.
As is the case with other harmful environmental problems, it is the people living at the bottom who bear the brunt of the damage. Bad urban air quality raises the risk of people suffering from a stroke, heart disease, lung cancer, and chronic and acute respiratory diseases.
“It is crucial for city and national governments to make urban air quality a health and development priority,” said Carlos Dora of the WHO, in a statement. “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.”
Overall, urban pollution levels increased by 8 percent between 2008 and 2013 globally. The new analysis does have a major gap – sub-Saharan Africa. Only 39 towns and cities from 10 countries in the region are included in the database right now because there is little information on particulate matter measurements for the region. What little data that WHO managed to collect shows that sub-Saharan African countries have levels exceeding the median.
High-pollution events have shut down cities for brief stretches in recent years, particularly in Asia. The negative effects of air pollution were well known, but new research is showing just how bad it can be. One new study connected air pollution with causing thousands of preterm births each year in the U.S. Children born too young are at much higher risk of developmental disability or death. It potentially adds billions of dollars in economic losses to an already tragic outcome for children and their families.
All becomes more concerning in places where air pollution levels are exceedingly high. The WHO recommends that cities have no more than 10 micrograms of particulate matter less than 2.5 micrometers in diameter per cubic meter of air (PM 2.5). The world’s most polluted city, Zabol, Iran, has a rate of 217 PM 2.5. The world’s 10 most polluted cities have rates exceeding 125 PM 2.5, with four cities in India, two in China, two in Saudi Arabia and one in Cameroon. All of those cities are in either developing countries or oil-rich states.
The data add another layer of urgency to take steps that will reduce carbon emissions and slow climate change. An estimated 12.6 million deaths, 23 percent of all global deaths, are attributed to environment risks. The majority of which are noncommunicable diseases that are more often than not caused by the most basic thing people need to live – air.
World leaders agreed in December during a climate conference in Paris to limit global warming to less than 2 degrees Celcius above pre-industrial levels. Achieving that goal will require less pollution generated by factories, vehicles and other sources. The air pollution trends are proof that change is needed fast, especially given projections that more and more people will live in urban areas over the next few decades.