New Delhi May 21, 2004: The Boston-based HEI’s report, Health Effects of Outdoor Air Pollution in Developing Countries of Asia: A Literature Review, recently released in New Delhi, puts existing health studies on air pollution in Asia under the scanner. In assessing existing evidence on the health toll of air pollution in Asian cities, the report found that with an increase of just 10 microgramme per cum of PM10 -- a key measure of pollution -- mortality increases by 0.5%, and with increased levels of nitrogen dioxide, hospital respiratory admissions increases by 1%.

Given the high levels of air pollution in many Asian cities (exceeding 100 microgramme/cum), the public health impact could be substantial, the study warns.

This Asia-wide review, conducted under the Public Health and Air Pollution in Asia Program (PAPA), was undertaken by HEI in partnership with the Clean Air Initiative for Asian Cities (CAI Asia) to help inform regional policy makers about the state of the science concerning air pollution and health in major Asian cities. Studies conducted in India were also selected for this review.

Daniel Greenbaum, President of HEI said on this occasion, "This Review is the first systematic identification of all peer reviewed Asian studies on the effects of air pollution on health. This found a considerable body of science currently exists across Asia, exceeding scientists’ expectations."

The review considered over 138 studies published between 1980 and 2003 that assessed the extent of illness and deaths in China, India, Indonesia, Japan, Malaysia, Thailand, Singapore and South Korea. Of these studies, only 28 qualified for further systematic analysis, based on their ability to meet pre-specified quality criteria. These included meeting a minimum data collection period of one year, use of statistical approaches to control for non-air pollution factors that could potentially affect the study outcome, and reporting in a manner that allows coherent comparison of approaches and results across cities.

Contd….

It is disquieting to note that out of 15 Indian studies considered for review – 6 from Mumbai, 5 from Delhi and 4 from other Indian cities, only one study on India, conducted by the World Bank, could meet the criteria for inclusion in the analysis. Although Indian studies have generated important local evidence, these are still much limited in scope, scale and method.

The Asian studies that qualified for inclusion however displayed almost the same pattern in the health impact being associated with the increase in air pollution, as observed in US and Europe.

HEI scientists were surprised by these similarities. They had good reasons to expect, as the report states, that the effects of air pollution would be influenced by the difference in age profile, health status and lifestyle between Asian and western populations, and also by the mixture and toxicity of pollutants. But studies reviewed so far in Asia do not show much variation from those observed elsewhere. Explains HEI vice president, Robert O Keefe, "The small number of cities considered for review limited the comparisons that can be made at this stage of analysis, but the estimated effects are similar to those found in the extensive studies conducted in western countries."

A key challenge for this analysis was that the majority of the Asian studies that could fulfill the criteria for the review are concentrated in the more developed regions of East Asia. Most studies were from South Korea – 11, followed by China – 6 and Hong Kong – 6, while the review included one study each from Taiwan, India, Singapore, Thailand, and Japan.

As a result, the findings are more influenced by the East Asian conditions and do not represent the full range of Asian settings. What the study cannot adequately capture at this stage therefore, is the influence of several unique features of Asia, such as the implication of very high levels of air pollution in South Asia (as compared to those in the US and Europe), and the susceptibility of poorer people to high levels of air pollution, an endemic problem in many Asian cities.

Many of these issues will be addressed in the new studies that have recently been initiated in Bangkok, Hong Kong, Shanghai, and Wuhan in China under this programme. Similar studies in India, and Southeast Asia are slated to begin in 2005. These studies are being designed to build Asian scientific and technical capacities to undertake these analyses.

In response to the findings of this report, CSE strongly urges the Indian government to immediately strengthen policy support to scientists in India, and to develop the country’s scientific capacities to be able to better assess the magnitude of risks from air pollution. This is urgently needed for better informed and guided policy to combat the air pollution crisis in the region.