A recent public outcry in China, sparked by a damning documentary about air pollution, was based on well-founded fear. Of the 100 million people who viewed the film on the first day of its online release, 172,000 are likely to die each year from air pollution-related diseases, according to regional trends.

Worldwide, pollution kills twice as many people each year as HIV/AIDS, malaria and tuberculosis combined, but aid policy has consistently neglected it as a health risk, donors and experts say. Air pollution alone killed seven million people in 2012, according to World Health Organization figures released last year, most of them in low and middle-income countries (LMICs) in the Asia Pacific region.***

In a self-critical report released late last month the World Bank acknowledged that it had treated air pollution as an afterthought, resulting in a dearth of analysis of the problem and spending on solutions.

“We now need to step up our game and adopt a more comprehensive approach to fixing air quality,” the authors wrote in Clean Air and Healthy Lungs. “If left unaddressed, these problems are expected to grow worse over time, as the world continues to urbanize at an unprecedented and challenging speed.”

A second report released last month by several organisations – including the Global Alliance on Health and Pollution, an international consortium of UN organisations, governments, development banks, NGOs and academics – also called for more funding towards reducing pollution.

“Rich countries, multilateral agencies and organisations have forgotten the crippling impacts of pollution and fail to make it a priority in their foreign assistance,” the authors wrote.

Housebound in China

A dense haze obstructs visibility more often than not across China’s northern Hua Bei plain and two of its major river deltas. Fewer than 1 percent of the 500 largest cities in China meet WHO’s air quality guidelines. Anger over air pollution is a hot topic among China’s increasingly outspoken citizenry.

“Half of the days in 2014, I had to confine my daughter to my home like a prisoner because the air quality in Beijing was so poor,” China’s well-known journalist Chai Jing said in Under the Dome, the independent documentary she released last month, which investigated the causes of China’s air pollution. The film was shared on the Chinese social media portal Weibo more than 580,000 times before officials ordered websites to delete it.

Traditionally left to environmental experts to tackle, the fight against pollution is increasingly recognised as requiring attention from health and development specialists too.

“Air pollution is the top environmental health risk and among the top modifiable health risks in the world,” said Professor Michael Brauer, a public health expert at the University of British Columbia in Canada and a member of the scientific advisory panel for the Climate and Clean Air Coalition, a consortium of governments and the UN Environment Program. “Air pollution has been under-funded and its health impacts under-appreciated.”

Pollution – especially outdoor or “ambient” air pollution – is also a major drag on economic performance and limits the opportunities of the poor, according to Ilmi Granoff, an environmental policy expert at the Overseas Development Institute, a London-based think tank. It causes premature death, illness, lost earnings and medical costs – all of which take their toll on both individual and national productivity.

“Donors need to get out of the siloed thinking of pollution as an environmental problem distinct from economic development and poverty reduction,” Granoff said. Pollution cleanup is indeed underfunded, he added, but pollution prevention is even more poorly prioritised: “It’s underfunded in much of the developed world, in aid, and in developing country priorities, so this isn’t just an aid problem.”

Mounting evidence

Pollution kills in a variety of ways, according to relatively recent studies; air pollution is by far the most lethal form compared to soil and water pollution.

Microscopic particulate matter (PM) suspended in polluted air is the chief culprit in these deaths: the smaller the particles’ size, the deeper they are able to penetrate into the lungs. Particles of less than 2.5 micrometers in diameter (PM2.5) are small enough to reach the alveoli, the deepest part of the lungs, and to enter the blood stream.

From there, PM2.5 causes inflammation and changes in heart rate, blood pressure, and blood clotting processes - the precursors to fatal stroke and heart disease. PM2.5 irritates and corrodes the alveoli, which impairs lung function - a major precursor to chronic obstructive pulmonary disease. It also acts as a carcinogen.

Most research looks at long-term exposure to PM2.5 but even studies looking at the hours immediately following bursts of especially high ambient PM2.5 (in developed countries) show a corresponding spike in life-threatening heart attacks, heart arrhythmias and stroke.

Asia worst affected

The overwhelming majority - 70 percent - of global air pollution deaths occur in the Western Pacific and Southeast Asia regions. South Asia has eight of the top 10 and 33 of the top 50 cities with the worst PM concentrations in the world.