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GLOBAL ENVIRONMENT OUTLOOK FOR YOUTH IN ASIA AND THE PACIFIC


Harmful substances can be present as small particles in the air, called particulate matter (PM). These vary in size, larger particles, PM10 and fine particulates, PM2.5, can come from both natural and human-made sources. Some PM is a part of the normal composition of outdoor air, such as sea salt from the oceans and loose dust, but many components of PM are toxic.


Air pollution is a threat that is present almost everywhere in the Asia-Pacific region: about 92 per cent of the total population is exposed to levels of air pollution that present a significant risk to their health. Knowing that the threat is affecting so many people, we are challenged to come up with effective solutions that will prevent the problem from getting worse over time.


Climate-altering air pollutants


When climate change comes to mind, most people think of excess levels of carbon dioxide (CO2) as the primary concern. New research shows, however, that


there are more substances in the atmosphere that require our attention: short-lived climate pollutants (SLCPs). These include black carbon, methane (CH4) and and ground-level ozone. While short lived, they only tend to stay in the atmosphere for short periods of time, these pollutants significantly affect local and global climate.


Black carbon, in the form of soot, decreases atmospheric visibility by producing persistent haze and smog over affected areas. It can also change local climate conditions by causing changes in temperature. Its overall effect in the atmosphere is to increase the temperature, although it can have a cooling effect, for example, after volcanic eruptions, as the particles


block some energy from the sun from reaching the Earth (Bond et al. 2013).


Methane is a greenhouse gas several times more effective in causing glbal warming than carbon dioxide that is mainly produced from rice paddies, livestock production and the breaking down of organic waste. Additionally, when methane interacts with other gaseous pollutants, such as nitrogen oxides, in the presence of sunlight it forms another air pollutant and greenhouse gas: ground-level ozone, which also impacts crop production.


Air pollution is a severe health hazard


Both short-term and long-term exposure to these air pollutants brings high risks to human health. The risks from PM depend on the particle size: smaller particles are more dangerous. PM10 (particles with diameter of 10 micrometres or less) are mostly trapped in the nose and throat while PM2.5 (particles with diameter of 2.5 micrometres or less) can be directly absorbed through lungs into the bloodstream, where they contribute to increased incidences of various lung and heart diseases, as well as cancer (van Berlo et al. 2012). This is due to the toxic components of PM2.5: it can contain black carbon, toxic metals such as lead, arsenic and cadmium, and polycyclic aromatic hydrocarbons (PAHs) which are carcinogenic molecules. These toxic particles are often produced from a range of sources including vehicle exhausts, burning of waste, use of charcoal and wood for cooking and heating and industrial processes,


Particulate matter pollution is the fifth most frequent cause worldwide of premature deaths and illnesses, as well as affecting people’s quality of life (Cohen et al.


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