Air quality

Danger to human health

The alarming message from the UN Industrial Development Organisation is that air pollution now causes more deaths than AIDs and malaria combined [1].

Evidence from the World Health Organisation (WHO) shows this to be the case even if deaths from outdoor air pollution alone are considered. In 2012, WHO reported that 3.7 million people die per year as a result of outdoor air pollution [2]. This is higher than the 1.7 million AIDs related fatalities in 2011 and the 660,000 deaths from malaria in 2010 [3]

A disturbingly wide range of serious conditions are caused by air pollution, including heart disorders and respiratory diseases such as asthma and lung cancer [4]. There is now a substantial amount of medical evidence identifying the harmful effects of air pollution on human health, with PM10 and PM2.5 recognised as the most directly harmful particulates.

Evidence collated by WHO in 2012 shows that the direct effects of air pollution are more serious than was previously realised [5]. In Asia’s developing countries, where air pollution levels are the highest in the world, health risks are particularly high [6]. Globally approximately 65% of fatalities resulting from air pollution occur in Asia [7].

Road transport’s detrimental impact

Economic growth in Asia has been accompanied by an increase in all forms of motorised transport. This has resulted in numerous cities exceeding the WHO air quality standards (AQS) for PM10 and NO2. In Metro Manila annual average PM10 levels are almost three times above the WHO AQS and in New Delhi levels rise to ten times above this health standard [1].

In Beijing, Shanghai, Guangzhou and Xi’an, PM2.5 pollution levels are higher than WHO air quality guidelines. If the WHO guidelines had been met in 2012, there would have been a reduction in premature deaths of 81% in these four cities [8].
Road transport is a major source of air pollution damaging the environment, health and quality of life for urban populations in Asia. A World Bank study noted that in three cities vehicles were the source of 70% of particulate exposure. In Delhi and Dhaka, transport is shown to cause the majority of Particulate, Carbon Monoxide, NO2, and Hydrocarbon emissions.

The combustion of fossil fuels in motor vehicles produces a cocktail of emissions including:

  • Particulate matter (PM10 and PM2.5)
  • Oxides of nitrogen and sulphur
  • Carbon monoxide
  • Unburned hydrocarbons

In sunny climates vehicle emissions undergo chemical reactions in the atmosphere and form secondary air pollutants – nitrogen dioxide, ozone and photochemical smog. The black carbon particles released as soot from diesel vehicles and ozone also contribute to global warming.

The impact of transport pollution leads to higher incidences of disease from air pollution amongst populations living near roads. In areas near roads people have on average smaller lungs and there is evidence of stunted child lung growth resulting in disease later in life. In metropolitan areas of Asia over 50% of the population live in proximity to a major road. Even a low prevalence of air pollution, however, may cause illnesses.

Positive impact of biomethane

Protecting public health and curtailing the economic costs of treatment are compelling reasons to improve air quality. Although governments have progressively tightened vehicle emission and fuel quality standards, motor vehicles continue to severely affect Asia’s air quality.

By 2035, the vehicle population in Asia is expected to be more than one billion. It is estimated that freight movement in Asia, accounting for 60% of transport emissions, will increase from 1 billion in 2000 to 8 billion in 2050.

To prevent air quality deteriorating further, decisive action is needed to adopt clean vehicle fuels. The use of biomethane as a vehicle fuel alleviates air pollution in urban areas , with the greatest health benefits achieved through reductions in particulate matter emissions.

[1] United Nations Industrial Development Organization, April 2013

[2] United Nations Environment Programme, April 2013

[3] Inhabitat, April 2013

[4] The Lancet, March 2013

[5] Health Effects Institute, December 2012

[6] ibid

[7] Centre for Science and Environment India

[8] Greenpeace East Asia

[9] Centre for Science and Environment India

[10] Ibid

[11] King's College London (The Guardian, March 2013) & Health Effects Institute, 2012

[12] The Lancet, March 2013

[12] Clean Air Inititative 10 Years of Partnership 2012

[12] Sustainability Energy Authority of Ireland

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