Presentation on theme: "Air Pollution, Poverty, and Health (APPH*) in Ho Chi Minh City: Assessing Inequalities in Exposure and Health Effects Sumi Mehta and Vu Xuan Dan (on behalf."— Presentation transcript:
Air Pollution, Poverty, and Health (APPH*) in Ho Chi Minh City: Assessing Inequalities in Exposure and Health Effects Sumi Mehta and Vu Xuan Dan (on behalf of all APPH collaborators) *TA 4714-VIE, funded by ADB, Health Effects Institute (HEI), and Government of Vietnam
Why the poor may suffer more health effects from air pollution (global perspective) The poor may suffer higher exposures to air pollution –Roadside exposures (occupational, commuting, residential) –Small and medium scale enterprises / Cottage industries –Use of solid fuels for cooking The poor may be more susceptible to air pollution –Poorer nutrition / immunosuppression –Higher incidence of diseases of poverty –Lack of timely or comprehensive access to health care
Limited evidence from the West, but clear need to explore in Asia Extrapolation of developed- country research to other populations is challenging, often inadequate –Different pollution sources and mixes –Different competing risk factors –Population characteristics addressed / overlooked –Health effects addressed / overlooked –Epidemiologic evidence base often only at low end of the exposure-response curve HEI reanalysis of US Cohort studies
Studying APPH: Why HCMC? High quality data on air, health, and SEP Qualified and enthusiastic local collaborators –Dept of Public Health –HCMC Environmental Protection Agency (HEPA): –Childrens Hospitals –Bureau of Statistics A rapidly developing country in the midst of the environmental risk transition Smith and Ezzati, 2005
Ho Chi Minh City Over 9 million people Rapid growth: ~ 200,000 people / year from >50% pop in Vietnam < 25 years of age ~3 million motorcycles, 500,000 cars Consistently high temperature (28.19°C,SD 1.41), humidity (73.7%, SD 7.48)
Studying APPH in HCMC: Objectives 1.Develop feasible approaches to studying air pollution, poverty, and health Methods appropriate for HCMC context Methods suitable for use in other cities - promote building an evidence base across Asian cities 2.Develop infrastructure for future studies of the health effects of air pollution in HCMC Technical capacity (epidemiologic methods, exposure assessment, analysis) Resources (data integration, equipment)
Studies on the health effects of air pollution in Asia, 1980 – Sep 2007* *Public Health and Air Pollution in Asia – Science Access on the Net (PAPA-SAN)
2 Project Components C1.Hospital Study Routinely collected data from C2.Household Study Prospective data collection from
Summary of hypotheses tested H 1 : the poor experience greater health impacts from ambient air pollution (C1 and C2) H 2 : the poor live in areas with more ambient air pollution (C2) H 3 : exposures of the poor are more closely linked to ambient air pollution (C2) H 4 : the poor are more vulnerable to ambient air pollution (C1) H 5 : the poor are more exposed to air pollution (C2)
C1: Hospital Study Assess the effects of short-term exposure to air pollution on hospital admissions from for acute lower respiratory infections (ALRI) in young children (<5 years of age) of HCMC –ALRI is a leading cause of death in young children of developing countries –Over 28,000 admissions for ALRI in children during the study period Assess whether there are there different effects by socio-economic position (SEP), i.e. in poor children vs. other children
Preliminary Results PM 10, Ozone, NO 2 and SO 2 associated with increased hospital admissions for ALRI in young children of HCMC. –Ozone effects consistently higher than PM effects. –Results consistent across analytic techniques (time series and case crossover analyses) Greatest challenge: around 60% of ALRI admissions occur during the rainy season, highest pollutant concentrations are observed in the dry season –How do we address negative confounding in the rainy season???
Do effects differ by SEP? –Impact of air pollution does not appear to differ by SEP (neither individual or group classification). However: Data from hospital financial records gives an underestimate of poverty status Analysis uses a single, daily, city-wide average concentration to represent population average exposure If exposure measurement error differs by social class, the ability to assess differences by SEP will be compromised
Air Quality Monitoring Station, District 2, HCMC
A HCMC Neighborhood in Transition, 2006
C2: Household study: the relationship between personal and ambient exposures in HCMC Estimate personal exposures to air pollution among the poor and the non-poor ambient air pollution other sources (cooking with solid fuels, cottage industries) Estimate prevalence of child and adult respiratory symptoms in HCMC Assess local perceptions of environment
Issues Explored What is the correlation between ambient air pollution concentrations and personal exposures? –Is this correlation different for the poor vs. the non-poor? Are the mean total exposures of the poor higher? Are the poors exposures to ambient air pollution higher? Are the poors personal exposures to other sources of air pollution higher?
Exposure Assessment Focus: primary caregivers of children < 5 Repeated (<10) measurements of daily average personal exposure over wet and dry seasons –PM 2.5 and PM 10 –NO/NO 2 –Elemental carbon Special attention to traffic exposure, incense, cottage industries (street food), tobacco smoke Parallel monitoring at fixed site monitors for comparison of personal vs. ambient concentrations
Household Sampling Scheme
Are the poor more exposed? Personal PM 2.5 Exposures, by District and SES* *Results of first 6 household visits
How do exposures of the poor and non-poor correlate with the ambient air quality data?
Intended Implications for Policy and Health Impact Assessment Global contribution: development of approaches to explore the relationship among air pollution, poverty, and health address key scientific questions: higher exposures, different pollutant mixtures, climatic conditions, and disease distributions Regional contribution: locally relevant base of air pollution and health science focus on ALRI, a disease of poverty responsible for a substantial burden of disease in children increased local capacity for future research
HCMC well equipped to conduct future research on health effects of air pollution Targeted technical assistance: training on study design, data management, statistical analysis Necessary infrastructure for personal exposure assessment (monitoring and analysis) –Personal exposure monitoring PM and elemental carbon (gravimetric samples) NO/NO 2 (passive samples) –Exposure Assessment laboratory (controlled temperature, relative humidity, glove box, microbalance, reflectometer, ion chromatography unit)
What next? Vietnam has addressed class-related disparities on many levels most inequities (i.e. nutritional deficiencies, differential access to health care) that confer increased susceptibility to air pollution may have been alleviated already –Will continued rapid economic growth broaden inequities in exposures (and health effects as a result) to air pollution? What are the implications for replication of methods and /or design of multi-city or regional research? –Different patterns of poverty / inequality result in different manifestations of exposure and susceptibility –How can targeted monitoring be used to characterize and estimate exposure misclassification in routinely collected data?