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Air pollution has become a curse for millions of city-dwellers in Asia, posing a mounting risk to the very young and very old, pregnant women and people with heart and respiratory problems, say experts.
“The levels of pollution in parts of China, India and elsewhere in Asia are just astronomically high and the health impacts are dramatic,” said Bob O’Keefe of the Health Effects Institute (HEI), a US not-for-profit research agency.
“This is a threat that was really under-estimated in the past,” said O’Keefe.
This week, Singapore grappled with record levels of air pollution, unleashed by land fires in neighbouring Indonesia.
In January, pollution in Beijing went off the scale of an air-quality monitor at the US embassy, and the city’s hospital admissions surged by 20 percent.
In August 2012, Hong Kong suffered its highest-recorded pollution, prompting the territory to urge vulnerable population groups to stay indoors.
HEI estimates, derived from an exceptionally detailed analysis called the Global Burden of Disease, say that some 3.2 million people around the world died prematurely from outdoor air pollution in 2010.
China and India together accounted for some 2.5 million of these deaths, sharing the tally roughly equally.
The death toll in China has risen by a third over 20 years, but worse pollution is only part of the reason. As China becomes more prosperous, its citizens are attaining greater ages, reaching 70 or 80 years or beyond—when people become more vulnerable to heart and respiratory stress from air pollution.
A study published last August in the journal Nature Climate Change estimated that forest and land fires in Southeast Asia kill an additional 15,000 people annually from air pollution during the El Nino weather phenomenon, when drier soil often causes blazes to go out of control. (There is no El Nino at present.)
An investigation by US researchers, published in February, found that among three million births recorded in nine countries in North and South America, Europe, Asia and Australia, there was a clear link between worse air pollution and lower birth weight.
Low birth weight—when a newborn weighs less than 2.5 kilos (5.5 pounds)—is associated with ill health, premature death and cognitive problems in later life.
Health experts point to two main dangers from air pollution.
One concerns particulate matter (PM)—the sooty specks emitted from fossil fuels, forest fires and land clearances.
Cathryn Tonne, at the London School of Hygiene and Tropical Medicine, points the finger at so-called PM2.5—particles measuring 2.5 micrometres across or less, or 30 times smaller than a human hair.
Mainly generated by the burning of coal and oil for power stations, and diesel and petrol for transport, these are many times more perilous than PM10 particles, which are 10 micrometres across, Tonne and colleagues found in research into heart deaths in England and Wales.
“We found that for every 10 microgrammes per cubic metre in PM2.5, there was a 20-percent increase in the death rate,” Tonne said.
By way of comparison, the WHO has a recommended maximum of 10 microgrammes of PM2.5 per cubic metre as an annual exposure—and a maximum over a 24-hour period of 25 microgrammes per cubic metre.
In the United States, the annual PM2.5 limit is a recommended 12 microgrammes per cubic metre, and in the European Union (EU), it is 25 microgrammes.
In Beijing’s smog scare in January, though, levels reached a whopping 993 microgrammes per cubic metre… almost 40 times the WHO’s advised safety limit.
The other big danger from air pollution is ozone, a triple molecule of oxygen that in the stratosphere is a vital shield against DNA-damaging sunlight, but at ground level—where it is typically created by a reaction between nitrogen oxides in traffic fumes and sunlight—it is an irritant for the airways.
Short-term spikes in ground-level ozone have long been linked to heart attacks and severe asthma.
But research conducted in the US, published in 2009, suggests that cumulative exposure is also a big risk factor. The probability of dying from respiratory disease rose by as much as 50 percent as a result of long-exposure to high concentrations of ozone.
India Gate can barely be seen through smog in Delhi. Around 4.3 million deaths in 2012 were caused by indoor air pollution, mostly from wood and coal stoves in Asia. Photograph: Louis Dowse/Corbis
The new figures are more than double previous estimates and suggest that outdoor pollution from traffic fumes and coal-burning, and indoor pollution from wood and coal stoves, kills more people than smoking, road deaths and diabetes combined.
Around 80% of the 3.7 million deaths from outdoor pollution came as a result of stroke and heart disease, 11% from lung diseases and 6% from cancers. The vast majority were in Asia, with 180,000 in the Americas and Europe combined, said the WHO.
Indoor air pollution led to 4.3 million deaths, of which 34% were caused by strokes, 26% heart diseases and 12% respiratory disease in children. Only 19,000 of these deaths were in rich countries, with the vast majority being in low- and middle-income countries. Because many people are exposed to both indoor and outdoor air pollution, the WHO said deaths attributed to the two sources cannot be added together.
“The risks from air pollution are now far greater than previously thought or understood, particularly for heart disease and strokes,” said Maria Neira, director of WHO’s department for public health, environmental and social determinants of health. “Few risks have a greater impact on global health today than air pollution; the evidence signals the need for concerted action to clean up the air we all breathe.”
South-east Asia, said the WHO, is now the most polluted region in the world, with 3.3 million deaths linked to indoor air pollution and 2.6 million deaths related to outdoor air pollution. This reflects the explosive growth of cities and industrial development in China and India, as well as continuing deep poverty in rural areas.
The new estimates are based not on an significant increase in pollution, but on improved knowledge of the links between air pollutants and heart diseases and cancers, in addition to known links with respiratory diseases. A 2008 WHO report estimated that outdoor pollution led to about 1.3 million deaths, while about 1.9 million people were killed by indoor pollution. A Lancet study last year suggested that the surge in car use in south and east Asia killed 2.1 million people prematurely in 2010. Last year, WHO’s cancer agency classified air pollution as a carcinogen, linking dirty air to lung and bladder cancer.
“Cleaning up the air we breathe prevents non-communicable diseases as well as reduces disease risks among women and vulnerable groups, including children and the elderly,” said Dr Flavia Bustreo, WHO assistant director general of family, women and children’s health. “Poor women and children pay a heavy price from indoor air pollution since they spend more time at home breathing in smoke and soot from leaky coal and wood cook stoves.”
Martin Williams, professor of air quality at the environmental research group, King’s College London, said: “This is an important study, and although the majority of attributable deaths occur in south-east Asia and the western Pacific, air pollution impacts on mortality and health are still a significant public health problem in Europe, including the UK.”
Air pollution is increasingly linked with ill health and deaths in rich countries as traffic emissions rise. In the US, air pollution causes about 200,000 early deaths a year, with emissions from cars and trucks causing 53,000 and power generation 52,000, according to MIT’s environment laboratory. California suffers most from air pollution, with 21,000 early deaths.
In Europe, poor air quality is the top environmental cause of premature deaths in the EU, causing more than 100,000 premature deaths a year and costing from £300bn-£800bn a year in extra health costs, said Janez Potočnik, the EU environment commissioner.
Air pollution causes 29,000 early deaths a year in the UK and similar numbers in France and Germany.
Public Health and Air Pollution in Asia (PAPA ) – A CAI-Asia Initiative Implemented through the Health Effects Institute
Air pollution in major cities across Asia routinely exceeds health-based guidelines established by the World Health Organization and others by significant amounts. Asian cities host some of the largest global population concentrations, concentrations that are grow ing rapidly as a result of in-migration. Exposure to unhealthy levels of air pollution in Asian cities is extensive and expanding on an annual basis. This has implications for both the public health and the economic well being of each country. In response, the Clean Air Initiative for Asian Cities (CAI-Asia) was recently launched by the Asian Development Bank and World Bank, as a multi-stakeholder alliance to assist Asian countries in their efforts to take action to reduce air pollution.
The prime information for government and industry action to address air pollution is often the availability of credible local health evidence documenting the impacts of air pollution on public health. To date, however, in Asia there have been relatively few such analyses, making it difficult to make the case with local officials who must weigh air quality actions amidst numerous other public health and economic challenges.
To address this need, CAI-Asia is supporting a new initiative –Public Health and Air Pollution in Asia (or PAPA) – to form alliances of Asian scientists and air quality officials, and their counterparts elsewhere in the world, to (1) produce a concise, rigorous, and understandable synthesis of all of the existing health studies in Asia, and (2) conduct and communicate the results of systematic, high-quality health analyses in four representative Asian cities. These analyses will be designed to provide specific local estimates of health impacts from air pollution that can be used in cost benefit analyses of the health and monetary benefits of reducing pollution. This information can thus inform public and private decisions on ambient air quality standards, air quality monitoring, and enhanced control programs.
Equally important, PAPA will also build Asian scient ific and technical capacity to continue producing these important analyses in the decades to come by both producing these first four analyses, and building a broader network of scientists and regulators throughout Asia to inform future decisions. As a result, Asian air quality will benefit in the near term from high quality local data to guide and inform near-term decisions. And, for many years in the future, governments, industry, lending agencies, WHO, NGOs, and others will benefit from a strengthened Asian scientific community that can produce the needed science and communicate that science effectively, in understandable terms, to decision makers. The importance of such data will only increase
as the first, least costly control actions are taken, and air pollution decreases, making the next step of action more expensive and challenging, and requiring cost-effectiveness to be demonstrated with high-quality local data.
PAPA is being organized under CAI-Asia as a leveraged partnership among government development agencies (U.S. AID), international lending agencies, foundations, industry, and local governments. To date, PAPA has attracted substantial commitments of support from foundations, US AID, and industry. Guided by the PAPA Advisory Committee – a multi-stakeholder technical advisory committee formed by CAI-Asia – PAPA will be managed by the Health Effects Institute, a respected international health research institute supported by both government and industry to provide high-quality, relevant, and credible science for decisions on air quality and health. Thus PAPA will draw on the extensive network of key stakeholders coming together as CAI-Asia, and the experience of HEI in conducting analyses and building scientific capacity in a number of countries, to produce targeted results and a sustainable network of Asian scientific expertise to inform decisions for the
decades to come.