The Health Effects Institute
PAPA-SAN: An Overview
Public Health and Air Pollution in Asia—
Science Access on the Net
A New Compendium of Studies
of the Health Effects of Air Pollution in Asia
Gathering evidence from a wider range of Asian cities and using a more systematic approach to analyze and report results helps us learn more about the health effects of air pollution in Asia and how these health effects compare to other regions of the world. PAPA-SAN brings together for the first time a web-accessible compendium of over 250 studies published in the past 25 years that provides substantial information on the effects of outdoor air pollution on the health of Asia’s people. This information can serve as a resource for Asian policy makers as well as scientists and the CAI-Asia network.
PAPA-SAN is a new, expanded Asia literature review created in response to interest in Special Report 15 from regional scientists and government policy makers. It includes the studies originally in Special Report 15, new Asia studies published in 2004 and 2006, and studies published between 1980 and 2003 that were not in Special Report 15—substantially increasing the total number of identified publications. The search methodology included formal criteria and defined document handling protocols. Computer searches of the scientific literature were made by subject heading, region, and country. These were augmented by reviews of leading Chinese journals of preventive medicine and epidemiology, and bibliographic references to published papers.
Summary of PAPA-SAN Results
Most Recent Update
As specified in the PAPA-SAN literature search manual, the database has been updated periodically through systematic searches every 12 months. In the most recent search, conducted in June 2006, 39 additional publications were identified and added into the existing database. These newly identified studies brought this web-based literature compendium up to date, with a new total of 279 publications. These 39 new publications reported studies completed in 5 Asian countries: China, India, Japan, Korea, and Thailand. Most of the newly identified publications focused on respiratory and cardiovascular outcomes, which continue to illustrate the adverse effect of ambient pollution in the area. Additionally, 7 publications on health impact assessment summarized economic losses resulting from air pollution. The updated literature search has thus further enriched the information available in PAPA-SAN.
Overall Results
The results of the updated literature search were published online in December 2006. The database includes a total of 279 publications that report ordinal estimates of the health effects of outdoor air pollution in Asia. These publications were published between 1980 and June 2006 in the peer-reviewed literature. Studies included were conducted in 8 countries (Figure 1). Most were conducted in East Asia (mainland China, Taipei,China, Hong Kong, Japan, and South Korea). A few were conducted in South Asia (India) and Southeast Asia (Thailand, Malaysia, Singapore, and Indonesia). Most were published in the last 10 years, a trend that is in keeping with the growth of similar Western literature over the period (Figure 2).
Figure 1: Epidemiologic studies of the health effects of air pollution in Asia (1980–2006). Numbers in parentheses show the total number of publications identified for each country. Click on a country to go to its results summary.
Figure 2: Number of publications of epidemiologic studies of air pollution in Asia by year of publication.
In 2006, published papers were collected through June.
Collectively, the 279 identified publications examined the association of exposure to particulate matter (PM) and gaseous pollutants with mortality, hospital admissions, respiratory symptoms, pulmonary function, and adverse reproductive outcomes. Most of these (177) described either cross-sectional prevalence studies of chronic respiratory symptoms or pulmonary function, or time-series studies of various short-term effects on daily mortality or hospital admissions. Most publications (158) estimated the health effects of ambient exposure to both PM (including TSP, RSP, PM10, and PM2.5) and gaseous pollutants (CO, NOx, SO2, and O3). The other publications estimated the effects of exposure to PM only (30 publications) or gaseous pollutants only (18 publications).
Characteristics of 279 Epidemiologic Studies of Outdoor Air Pollution in Asia (1980–2006)Number of publications a Health Outcome Mortality 74 Hospital admissions, visit, discharge 42 Respiratory disease, symptoms, function, asthma 135 Biomarker 10 Birth outcomes 19 Lung cancer 13 Economic assessment index 9 Others 30 Study design Ecologic 14 Time series b 76 Cross section b 101 Case control 8 Case crossover 13 Panel b 22 Cohort b 27 Health impact 18 Descriptive b 2 Unspecific 2 Exposure TSP 96 PM10 83 PM2.5 12 NOx 132 SO2 153 CO 59 O3 62 Nonspecific 76 Others 20 a In some studies, more than one outcome or exposure was described, or more than one design was used; b Includes episode studies. Looking ahead, PAPA-SAN will be updated once more in the spring of 2007. In 2008 HEI will issue a comprehensive report reviewing the Asia studies included in PAPA-SAN. The upcoming report will also include selected analyses of study subsets as well as summary results of 7 ongoing PAPA time-series studies (supported by HEI) that estimate the effects of short-term exposure to air pollution on daily mortality and morbidity in cities in China, Thailand, and India.
Your comments and feedback are very important to us to keep our work relevant and informative. Please contact us at PAPA@healtheffects.org with any suggestions you may have or if you have identified pertinent Asian studies or publications not already included in PAPA-SAN. Your attention and assistance are highly appreciated.
Abbreviations and other terms
Study designs commonly used
Ambient exposures commonly studied
The World Health Organization (WHO) estimates that urban air pollution contributes to approximately 800,000 deaths and 4.6 million lost life-years worldwide per year (WHO 2002). This burden is not equally distributed: approximately two-thirds of the deaths and lost life-years occur in the developing countries of Asia. Such estimates play an important role in decision making in a variety of policy contexts, from the setting of air quality guidelines to establishing public health priorities and international lending. WHO’s estimates suggest that the health impact of outdoor air pollution in Asian cities is substantial and warrants the attention of policy makers. The estimated impact is based largely on the results of research conducted in Europe and North America that have been extrapolated to other countries. While many similarities exist, the nature of air pollution in Asia, as well as the conditions and magnitude of pollution exposure, differs from those in the West. The socioeconomic status, health status, and levels of health care of Asian populations also differ from those of the West. Because of this, extrapolations from Western research results can sometimes create uncertainties in estimating health impacts in Asia.
PAPA Program
In December 2002, to help reduce these uncertainties, HEI initiated the Public Health and Air Pollution in Asia (PAPA)
( 70 KB) program, in partnership with CAI-Asia, to collect and review research on the health effects of air pollution in Asia, to support new studies of these health effects in seven Asian cities (Bangkok, Chennai, Delhi, Hong Kong, Ludhiana, Shanghai, Wuhan), and to build the capacity of scientific communities to conduct such studies and communicate their results effectively to key policy makers in government, industry, international lenders, and other stakeholders.
Special Report 15
An important initial contribution of the PAPA program was Special Report 15: Health Effects of Outdoor Air Pollution in Developing Countries of Asia: A Literature Review, published by HEI in April 2004 (with summaries in English and Chinese). Special Report 15 consisted of a systematic and critical review of the epidemiologic evidence concerning air pollution and health effects in the developing countries of Asia. It was prepared by PAPA’s International Scientific Oversight Committee (ISOC), a panel of leading independent scientists from around the world, to guide the development of PAPA’s research program and to be a resource for policy makers.
Special Report 15 provided a partial quantitative summary of what was known about the health effects of outdoor air pollution in Asia, focusing on estimates of the effects of short-term exposure. It brought together for the first time a previously unrecognized body of scientific literature that:
- identified and summarized original epidemiologic studies of outdoor air pollution in Asia that had been published in the peer-reviewed scientific literature between 1980 and 2003;
- examined in detail a subset of time-series studies that estimated the effects of short-term exposure to air pollution on daily mortality and hospital admissions for cardiovascular and respiratory diseases;
- put results in a context of broader air pollution and health science; and
- identified the gaps in knowledge that should be addressed in future research.
Reference
World Health Organization. 2002. The World Health Report 2002: Reducing Risks, Promoting Healthy Life. WHO, Geneva, Switzerland.
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