Outdoor Air Pollution in Southeast Asia
Air pollution is the presence of pollutants in the air that are harmful to the health of both humans and the planet.[i] Air pollution is the fourth greatest health risk factor, right after high blood pressure, smoking and high blood sugar. A study by the Global Burden of Disease found that 3.4 million people died prematurely in 2017 due to outdoor air pollution. [ii]
Outdoor air pollution commonly refers to air pollution that occurs outside of a building. Although there are many sources of outdoor air pollution (e.g. the agriculture sector, which we covered in our previous article here), the main anthropogenic sources are energy consumption and production.[iii] Other non-anthropogenic sources include bushfire, windblown dust, and biogenic emissions from pollen and mould spores. Conventionally, air pollutants of outdoor air pollution include particulate matter (PM10 and PM2.5), ozone, nitrogen dioxide, carbon monoxide, and sulphur dioxide. When these particles are released into the air, they form smog, soot, and acid rain that are detrimental to both our ecosystem and other non-living objects. Outdoor air pollution is known to be a risk factor for stroke, heart disease, lung cancer, and respiratory diseases. [iv] However, global death rates from air pollution have declined over time. Since the 1990s, particulate matter death rates have declined to 38 deaths per 100,000.[v][vi]
Particulate pollution includes particulate matter 10 (PM10) and PM2.5. Particulate matter pollution refers to the inhalable particles suspended in the air. PM10 refers to particles that have a diameter of less than 10 µm, while PM2.5 refers to particles that have a diameter of less than 2.5 µm. Particles like dust, pollen, mould spores are mostly PM10 and combustion particles, organic compounds and metal are mostly PM2.5.[vii] Since these particulate matters are microscopic, they may not be fully filtered by the lungs. Their size allows them to get deep into our lungs and some even into our bloodstream, making them a threat to health.
The mean exposure to PM2.5 in Southeast Asia countries has decreased since 2010. However, Singapore has been unable to significantly reduce the PM2.5 pollution in its city. The World Health Organization (WHO) has laid out the Air Quality Guidelines as a recommendation for limiting the health risk of air pollution. WHO recommends limiting the average exposure to PM2.5 to 10 micrograms per cubic meter, while also setting three interim target levels of 35, 25 and 10 micrograms per cubic meter. The mean exposure to PM2.5 in most countries is above this threshold, with the only exception being Brunei. However, the mean exposure of PM2.5 in Indonesia, Malaysia, the Philippines, and Singapore have reached the 15 micrograms per cubic meter 3rd interim target level set by WHO.
In most Southeast Asian countries, almost all of their population are exposed to air pollution levels above the WHO threshold. However, countries such as Indonesia, Malaysia and the Philippines have made positive progress over the years.
We observe that in Southeast Asia, countries with lower mean PM2.5 exposure tend to have higher GDP per capita. However, their mean PM2.5 exposure decreases at a smaller intensity as compared to those that have higher mean PM2.5 exposure.
Besides outdoor air pollution, indoor air pollution is also a risk factor for mortality, and it is more significant in lower-income countries. Indoor air pollution mainly stems from the burning of cooking fuels in enclosed households. Among low-income households, the more common cooking fuels include crop waste, dung and firewood, which usually results in incomplete combustion and produce a huge amount of pollutants when compared to solid fuels and non-solid fuels.[viii] The access to clean fuel and technology for cooking among Cambodia, Indonesia, and Myanmar has been increasing greatly since 2000. However, access across the region remains low.
[i] Mackenzie, J., “Air Pollution: Everything You Need to Know”, Natural Resources Defense Council, 1 Nov 2016, Accessed 27 Feb 2021, https://www.nrdc.org/stories/air-pollution-everything-you-need-know#sec1.
[ii] Ritchie, H. and Roser, M., “Outdoor Air Pollution”, Our World in Data, Nov 2019, Accessed 27 Feb 2021, https://ourworldindata.org/outdoor-air-pollution#outdoor-air-pollution-is-one-of-the-leading-risk-factors-for-premature-death.
[iii] Ibid.
[iv] Ibid.
[v] Ibid.
[vi] Although we wanted to reproduce a graph from the data from the Global Burden of Disease study under the factors “Ambient ozone pollution” and “Ambient particulate matter pollution”, the option is no longer available from http://ghdx.healthdata.org/gbd-results-tool.
[vii] Thongplang, J., “Particulate Matter: Why monitor PM10 and PM2.5”, Aeroqual, 5 Feb 2021, Accessed 27 Feb 2021, https://www.aeroqual.com/particulate-matters-why-monitor-pm10-and-pm2-5.
[viii] Ritchie, H. and Roser, M., “Outdoor Air Pollution”, Our World in Data, Nov 2019, Accessed 27 Feb 2021, https://ourworldindata.org/outdoor-air-pollution#outdoor-air-pollution-is-one-of-the-leading-risk-factors-for-premature-death.
