An explosion of car use has made fast-growing Asian cities the epicentre of global air pollution and become, along with obesity, the world’s fastest growing cause of death according to a major study of global diseases.
In 2010, more than 2.1m people in Asia died prematurely from air pollution, mostly from the minute particles of diesel soot and gasses emitted from cars and lorries. Other causes of air pollution include construction and industry. Of these deaths, says the study published in The Lancet, 1.2 million were in east Asia and China, and 712,000 in south Asia, including India.
Worldwide, a record 3.2m people a year died from air pollution in 2010, compared with 800,000 in 2000. It now ranks for the first time in the world’s top 10 list of killer diseases, says the Global Burden of Disease (GBD) study.
Lancet – A comparative risk assessment of burden of disease and injury attributable to 67 risk factors and risk factor clusters in 21 regions, 1990—2010: a systematic analysis for the Global Burden of Disease Study 2010
In 2010, the three leading risk factors for global disease burden were high blood pressure (7·0% [95% uncertainty interval 6·2—7·7] of global DALYs), tobacco smoking including second-hand smoke (6·3% [5·5—7·0]), and alcohol use (5·5% [5·0—5·9]). In 1990, the leading risks were childhood underweight (7·9% [6·8—9·4]), household air pollution from solid fuels (HAP; 7·0% [5·6—8·3]), and tobacco smoking including second-hand smoke (6·1% [5·4—6·8]). Dietary risk factors and physical inactivity collectively accounted for 10·0% (95% UI 9·2—10·8) of global DALYs in 2010, with the most prominent dietary risks being diets low in fruits and those high in sodium. Several risks that primarily affect childhood communicable diseases, including unimproved water and sanitation and childhood micronutrient deficiencies, fell in rank between 1990 and 2010, with unimproved water and sanitation accounting for 0·9% (0·4—1·6) of global DALYs in 2010. However, in most of sub-Saharan Africa childhood underweight, HAP, and non-exclusive and discontinued breastfeeding were the leading risks in 2010, while HAP was the leading risk in south Asia. The leading risk factor in Eastern Europe, most of Latin America, and southern sub-Saharan Africa in 2010 was alcohol use; in most of Asia, North Africa and Middle East, and central Europe it was high blood pressure. Despite declines, tobacco smoking including second-hand smoke remained the leading risk in high-income north America and western Europe. High body-mass index has increased globally and it is the leading risk in Australasia and southern Latin America, and also ranks high in other high-income regions, North Africa and Middle East, and Oceania.
65% of all air pollution deaths are now in Asia, which lost 52m years of healthy life from fine particle air pollution in 2010. Air pollution also contributes to higher rates of cognitive decline, strokes and heart attacks.
If the figures for outdoor air pollution are combined with those of indoor air pollution, caused largely by people cooking indoors with wood, dirty air would now rank as the second highest killer in the world, behind only blood pressure.
Household air pollution from burning solid fuels such as coal or wood for cooking fell noticeably, but not having clean cooking and heating fuels remains the leading risk in south Asia.
Fine particle air pollution in India is far above the legal limits of 100 microgramme per cubic metre. This can rise to nearly 1,000 microgrammes during festivals like Diwali.
Improvements in car and fuel technology have been made since 2000 but these are nullified by the sheer increase in car numbers. Nearly 18m are expected to be sold this year alone. In Delhi, there are now around 200 cars per 1,000 people compared with 70-100 per 1,000 population in Hong Kong and Singapore.