Around 98 percent of cities in low- and middle-income countries with more than 100,000 inhabitants have air pollution levels that exceed WHO guidelines, with the South East Asia region registering an increase of over five percent increase in dirty air over the five years, a new UN study revealed.
A database released by the World Health Organisation (WHO) compares a total of 795 cities across 67 countries for levels of small and fine particulate matter (PM10 and PM2.5) during the five-year period, 2008-2013. PM10 and PM2.5 include pollutants such as sulfates, nitrates and black carbon. PM2.5 are very fine particles that can penetrate deep into the respiratory system and can be directly linked to the greatest risks to human health for stroke, heart disease, lung cancer, and chronic and acute respiratory diseases, including asthma.
Overall, 80 percent of people living in urban areas that monitor air pollution are exposed to air quality that do not meet WHO guidelines. “The trend is for worsening air pollution in low-and middle-income countries overall and improving air quality in the higher-income country,” said WHO’s Dr Carlos Dora. The number of exposed people in urban centres to pollution-heavy air falls to 56 percent for high-income countries. WHO called the overall trend “worrying”.
The annual mean PM2.5 levels for a few busy cities were: Beijing 85 μg/m3, Shanghai 52 μg/m3 , Islamabad 66 μg/m3 (for 2011 collected from one station), Istanbul 33 μg/m3 (for 2012), Paris 18μg/m3 (for 2014), London 15 μg/m3 (for 2013) and New York-Northern New Jersey 9 μg/m3 (for 2014).
WHO does not rank countries but merely reproduces data from the government and other sources and analyses them.
One of the worst quality of air for the 3000 cities which find a mention in this WHO database is the Iranian city of Zabol with PM2.5 levels recording a whooping 217 μg/m3 dirty particles in 2012. One of the cleanest airs is of the Arctic city of Kiruna which had only 2 μg/m3 of PM2.5 in 2013.
WHO’s air quality guidelines recommend keeping PM2.5 levels within 10 μg/m3 for annual mean numbers and 20 μg/m3 annual mean for PM10 levels.
Urban air pollution continues to rise at an alarming rate, wreaking havoc on human health,” says Dr Maria Neira, WHO Director, Department of Public Health, Environmental and Social Determinants of Health.
However, the good news is that more than half of the monitored cities in high-income countries and more than one-third in low- and middle-income countries reduced their air pollution levels by more than five percent in five years.
“It is possible to do things even if you are low-and middle-income countries to improve your air quality and it is being shown,” Dr. Dora said.
PM10 levels for 39 cities selected across WHO regions for the period between 2011-2015 show Riyadh to be, by far, the most polluted city with dirty particulates of 370 μg/m3 in the air followed by Doha (about 260 μg/m3), Delhi (about 225 μg/m3), Greater Cairo, Dakar and Ulanbator. The lowest in the comparative chart is Toronto.
PM10 levels of 11 mega cities with more than 14 million habitants between 2011 and 2015 shows Delhi (about 225 μg/m3) to be the most polluted followed by Cairo (175 μg/m3), Dhaka (160μg/m3), Kolkata (140 μg/m3), Mumbai (120 μg/m3), Beijing (110 μg/m3), Shanghai (75 μg/m3). Istanbul, Mexico City, Sao Paulo and Buenos Aires follow Shanghai in ambient urban air pollution levels.
Annual mean PM10 measurements could be accessed in only 586 cities in low-and middle-income countries.
Indian cities don’t fare very well on this database. The annual mean PM2.5 levels — that represents the greatest environmental risks to health—are alarmingly high above the UN health agency’s guidelines for most cities. Some of the most choked air is in Gwalior (176 μg/m3) followed by Allahabad (170 μg/m3), Raipur (144 μg/m3) Ludhiana (122 μg/m3), Delhi (122 μg/m3), Lucknow (113μg/m3) The numbers for all cities are for 2012 while for Delhi the level has been calculated from 2013.
Only Tezpur with an annual mean PM2.5 level of 6 μg/m3 has air comparable to European cities.
Ambient air pollution is the greatest environmental risk to health—causing more than 3 million premature deaths worldwide ever year.
The odd-even road rationing policy adopted in some cities of the world like Delhi and Mexico is “very useful” but is essentially a stopgap arrangement because they improve things “momentarily”, Dr Dora told Firstpost.
“But in the long-term you need more structural measures. You need better transportation systems, rapid bus transit system, you need space for cycles, you need space for pedestrians, reduction in the number of vehicles which are on the road vis-à-vis the number of people (etc.),” the expert added.
Describing the challenges in India as huge, the WHO said that cooking with wood, coal or kerosene is a very big problem in the country. “India has 400 million homes using kerosene for lighting, still. Even if they are doing solar which is very good… it’s a lot of particles, it is very bad stuff. And it is easily solved because you have solar lamps that are very effective, they are cheap,” he said.
India, Bangladesh and China where more and more cities are “going in the wrong direction”, waste burning is one of the biggest causes of air pollution, the experts said. The dominant reasons for dirty air is different for countries across the world. For instance, in New York 50 percent of the outdoor air pollution comes from heating and cooling of a few, large buildings. However, in Europe, in many parts it is ammonia contained in fertilisers that is the cause while in Africa dirty sources of electricity play a big role in clogging the air.
“Most sources of urban outdoor air pollution are well beyond the control of individuals and demand action by cities, as well as national and international policymakers to promote cleaner transport, more efficient energy production and waste management,” the WHO said in a statement.
During the World Health Assembly to be held later this month governments will huddle together to discuss a road map for an enhanced global response to the adverse health effects of air pollution.
Updated Date: May 12, 2016 14:49 PM