Photo by AFP/Greg Baker
29 Aug 2024 Story Air quality

亚洲国家如何通过解决空气污染来拯救生命、促进经济增长

Photo by AFP/Greg Baker

For the people of East and Southeast Asia air pollution has become an all too familiar sight.  

More than 90 per cent of the region’s 2.5 billion people breathe air that is considered unsafe by the World Health Organization. That dirty air – a combination of everything from tailpipe emissions to forest fire smoke – is responsible for millions of premature deaths each year. 

“Air pollution is one of the greatest health threats facing this region right now,” says Dechen Tsering, regional director and representative of the United Nations Environment Programme (UNEP) for Asia and the Pacific. “But the good news is that it’s not an impossible problem to solve. We know how to reduce air pollution – we just need to act.” 

On 7 September, the world will celebrate the International Day of Clean Air for blue skies, which is designed to supercharge the global effort to tackle air pollution. Ahead of the observance, here’s a closer look at the scale of air pollution in East and Southeast Asia, its impact on human health and how countries can free themselves from its deadly grasp. 

An aeroplane flies over a road in Chiang Mai, Thailand.
An aeroplane flies over a road as it lands at Chiang Mai International Airport amid high levels of air pollution in Chiang Mai, Thailand on March 15, 2024.  Photo by Lillian Suwanrumpha/AFP

The two most damaging types of air pollution in Asia and the Pacific are fine particulate matter and ground-level ozone. Fine particulate matter refers to a group of microscopic substances that measure less than 2.5 microns – just a fraction of the width of a human hair. These particles come primarily from the burning of fossil fuels and biomass, such as trees. They’re especially dangerous because their tiny size allows them to penetrate deep into the lungs and enter the bloodstream, triggering heart disease and lung cancer, among other potentially fatal diseases.

Ground-level ozone, a gas, forms when fuel vapours, chemical solvents and other pollutants are heated by the sun. It is the main ingredient in smog and has been linked to a litany of respiratory problems, including asthma, emphysema and chronic bronchitis. It can also slow photosynthesis, hampering plant growth. 

Nearly everyone who calls East and Southeast Asia home breathes polluted air and nine countries in the region are ranked among the world’s 40-most polluted nations in 2023, according to data from UNEP partner IQAir.  

Live data from UNEP showed that on a typical mid-August day this year, more than 98 per cent of people in China, Japan, Laos, the Republic of Korea and Vietnam breathed in air with PM2.5 levels that exceeded World Health Organization guidelines.  

Map showing air pollution exposure in cities in Southeast and East Asia
The boundaries and names shown and the designations used on this map do not imply official endorsement or acceptance by the United Nations. Source: IQAir/UNEP

In the map above, only those cities represented by blue dots – which are clustered around northern Japan and the Gulf of Thailand – had air the WHO considers clean.  

Much of the poor air quality is being driven by the burning of fossil fuels for power generation, industry and transport, the burning of biomass, such as firewood, for home cooking, heating and lighting, and the unregulated burning of rubbish and crop leftovers. 

The effects of this air pollution are devastating. Among regions, Southeast Asia, East Asia and Oceania had the second-highest rate of premature death from PM2.5 in 2021, trailing only the Middle East and North Africa. China (2.3 million deaths), Indonesia (221,600 deaths), Myanmar (101,600 deaths) Vietnam (99,700 deaths) and the Philippines (98,200 deaths) were hit especially hard.  

A series of recent reports, supported by UNEP, looked at air pollution trends in Cambodia, Indonesia and Thailand. In those countries, five common pollutants – carbon dioxide, nitrogen oxide, PM2.5, sulfur dioxide and ammonia – are all edging upwards.  

The reports found the three nations could save a combined 230,000 lives by taking meaningful steps to reduce air pollution. The vast majority of those spared would be in Indonesia where air pollution is expected to contribute to more than 200,000 premature deaths annually by 2030.

Graph showing annual premature deaths due to PM2.5 by 2030 in Cambodia, Indonesia and Thailand.
Graph showing annual premature deaths due to PM2.5 by 2030 in Cambodia, Indonesia and Thailand. Source: UNEP/International Institute for Applied Systems Analysis 

The same reports found the three countries could save nearly US$60 billion combined in healthcare costs through 2030 by developing policies to counteract air pollution. Those measures could dramatically reduce hospital admissions for asthma and respiratory diseases, among other conditions.  

Graph showing annual cost of air pollution by 2030 in US dollars in Cambodia, Indonesia and Thailand.
Graph showing annual cost of air pollution by 2030 in US dollars in Cambodia, Indonesia and Thailand. Source: UNEP/International Institute for Applied Systems Analysis 

Limiting air pollution wouldn’t only save lives and money. It would also help counter climate change. That’s because many of the substances that pollute the air, like methane, a gas, and black carbon, a form of PM2.5, also trap the sun’s heat, accelerating global warming.  

While these substances have relatively short lives in the atmosphere, they cause far more warming per unit of mass than the most common greenhouse gas, carbon dioxide.   

By investing in renewable energy, imposing stricter vehicle emission standards and fostering the transition to electric cars, Indonesia, for example, could improve its air quality and reduce its greenhouse gas emissions by 650 megatonnes. That is equivalent to taking 130 million cars off the road.  

While the reports only covered three countries, their findings could be applicable to much of East and Southeast Asia, says UNEP’s Tsering. 

“Too often, countries worry about how much it will cost to reduce air pollution,” she says. “But this UNEP data shows that there is a massive cost, both in terms of lives and money, to inaction.” 

Smoke billowing from stacks
UNEP data shows countries could save hundreds of thousands of lives and billions of dollars by reducing air pollution. Photo: AFP/STR

Experts say there are several things the countries of East and Southeast Asia can do to reduce air pollution. They include: 

  • investing in renewable energy 
  • embracing electric vehicles 
  • improving waste management and ending the open burning of rubbish 
  • bringing an end to the open burning of crops 
  • helping people access cleaner-burning fuels, like natural gas, for cooking 

UNEP data found that while there would be a cost to these measures, it would pale in comparison to the amount of money lost to healthcare bills and flagging productivity. In Thailand, for example, the cost of implementing clean air strategies would be about US$4 billion annually by 2030. The cost of inaction would be triple that. 

Graph showing the cost of inaction in US dollars in Cambodia, Indonesia and Thailand.
Graph showing the cost of inaction in US dollars in Cambodia, Indonesia and Thailand. Source: UNEP/International Institute for Applied Systems Analysis. 

“It just makes sense on so many levels for countries to get serious about air pollution,” says UNEP’s Tsering. “Without a doubt, some nations have made progress in recent years. But we need to dramatically scale up action if we’re to unlock this region’s potential and help people live longer, healthier lives.” 

The UN Environment Programme strengthens the capacity of governments to work for clean air by enhancing the understanding of air pollution and catalysing transformative actions and policies. Through the Asia Pacific Regional Forum on Health and the Environment, UNEP contributes to the cooperation of the health and environment sectors in the region to address environmental and health issues, such as air pollution. The Forum joint secretariat is hosted by UNEP and the World Health Organization. 

The International Day of Clean Air for blue skies, held annually on 7 September and facilitated by the UN Environment Programme (UNEP), raises awareness about the importance of clean air for health, productivity, the economy and the environment. This year’s theme “Invest in #CleanAirNow” underscores the economic, environmental and health benefits of investing in clean air.