Air pollution in major cities in Asia exceeds the World Health Organisation's (WHO) air quality guidelines and toxic cocktails result in more than 530,000 premature deaths a year, according to a new report issued on Tuesday
Outdoor Air Pollution and Health in the Developing Countries of Asia: A Comprehensive Review, is the first comprehensive literature review to come out of the U.S.-based Health Effects Institute, Public Health and Air Pollution in Asia (PAPA) program.
The study notes that Asia is undergoing economic development at a rapid rate, resulting in levels of urban air pollution in many cities that rival the levels that existed in Europe and North America in the first decades of the 20th century. This development is also transforming the demographic and epidemiologic characteristics of the population in ways that are likely to affect its vulnerability to air pollution.
In rural areas and urban slums, indoor air pollution from the burning of solid fuels confers its own large burden of disease and contributes to increased outdoor concentrations of pollutants in some locales.
Developing Asia's poorest populations are also susceptible to the unexpected effects of climate change, including possibly substantial health effects.
The review builds on an initial assessment conducted in 2004 and describes the current scope of the Asian literature on the health effects of outdoor air pollution, enumerating and classifying more than 400 studies.
In addition, the report includes a systematic and quantitative assessment of 82 time-series studies of daily mortality and hospital admissions for cardiovascular and respiratory disease.
The studies covered in the current review include the PAPA time-series studies in four Asian cities as well as a first-ever critical and qualitative analysis of Asian studies of long-term exposure to air pollution and chronic respiratory disease, lung cancer, and adverse reproductive outcomes that describes both what the studies tell us and the continuing uncertainties and research needs.
Based on findings from more than 80 Asian time-series studies, including coordinated multi-city time-series studies, the same pollutants - RSP and gaseous pollutants such as ozone (O3), SO2, and NO2 - affect older people with chronic cardiovascular or respiratory disease.
The adverse effects in some locales may reflect the effects of air pollution concentrations that have subsequently decreased. However, more recent studies continue to report adverse effects at lower levels in cities in Thailand and Japan, where air quality has improved, as well as in heavily polluted Chinese and Indian cities.
The report also provides a broad overview of the status of and trends in air pollution sources, emissions, and exposures in the developing countries of Asia, as well as factors related to urban development, population health, and public policy that set the context for the public health effects of air pollution.
The review concludes by placing the Asian health effects studies in the context of the worldwide literature, identifies gaps in knowledge, and recommends approaches by which to address them.