Presentation on theme: "Sumi Mehta and Vu Xuan Dan (on behalf of all APPH collaborators)"— Presentation transcript:
1Sumi Mehta and Vu Xuan Dan (on behalf of all APPH collaborators) Air Pollution, Poverty, and Health (APPH*) in Ho Chi Minh City: Assessing Inequalities in Exposure and Health EffectsSumi 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
2Why the poor may suffer more health effects from air pollution (global perspective) The poor may suffer higher exposures to air pollutionRoadside exposures (occupational, commuting, residential)Small and medium scale enterprises / Cottage industriesUse of solid fuels for cookingThe poor may be more susceptible to air pollutionPoorer nutrition / immunosuppressionHigher incidence of ‘diseases of poverty’Lack of timely or comprehensive access to health care
3Limited evidence from the West, but clear need to explore in Asia Extrapolation of developed-country research to other populations is challenging, often inadequateDifferent pollution sources and mixesDifferent competing risk factorsPopulation characteristics addressed / overlookedHealth effects addressed / overlookedEpidemiologic evidence base often only at low end of the exposure-response curveHEI reanalysis of US Cohort studies
4Studying APPH: Why HCMC? High quality data on air, health, and SEPQualified and enthusiastic local collaboratorsDept of Public HealthHCMC Environmental Protection Agency (HEPA):Children’s HospitalsBureau of StatisticsA rapidly developing country in the midst of the environmental risk transitionSmith and Ezzati, 2005
5Ho 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 carsConsistently high temperature (28.19°C,SD 1.41), humidity (73.7%, SD 7.48)
6Studying APPH in HCMC: Objectives Develop feasible approaches to studying air pollution, poverty, and healthMethods appropriate for HCMC contextMethods suitable for use in other cities - promote building an evidence base across Asian citiesDevelop infrastructure for future studies of the health effects of air pollution in HCMCTechnical capacity (epidemiologic methods, exposure assessment, analysis)Resources (data integration, equipment)
7Studies 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)
82 Project Components C1. Hospital Study C2. Household Study Routinely collected data fromC2. Household StudyProspective data collection from
9Summary of hypotheses tested H1: the poor experience greater health impacts from ambient air pollution (C1 and C2)H2: the poor live in areas with more ambient air pollution (C2)H3: exposures of the poor are more closely linked to ambient air pollution (C2)H4: the poor are more vulnerable to ambient air pollution (C1)H5: the poor are more exposed to air pollution (C2)
10C1: Hospital StudyAssess 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 HCMCALRI is a leading cause of death in young children of developing countriesOver 28,000 admissions for ALRI in children during the study periodAssess whether there are there different effects by socio-economic position (SEP), i.e. in poor children vs. other children
11Daily Hospital Admissions for ALRI Daily Ambient Pollutant Concentrations (city level)Daily Hospital Admissions for ALRI
12Preliminary ResultsPM10, Ozone, NO2 and SO2 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 seasonHow do we address negative confounding in the rainy season???
13Do 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 statusAnalysis uses a single, daily, city-wide average concentration to represent population average exposureIf exposure measurement error differs by social class, the ability to assess differences by SEP will be compromised
14Air Quality Monitoring Station, District 2, HCMC
16C2: Household study: the relationship between personal and ambient exposures in HCMC Estimate personal exposures to air pollution among the poor and the non-poorambient air pollutionother sources (cooking with solid fuels, cottage industries)Estimate prevalence of child and adult respiratory symptoms in HCMCAssess local perceptions of environment
17Issues ExploredWhat 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 poor’s exposures to ambient air pollution higher?Are the poor’s personal exposures to other sources of air pollution higher?
18Exposure Assessment Focus: primary caregivers of children < 5 Repeated (<10) measurements of daily average personal exposure over wet and dry seasonsPM2.5 and PM10NO/NO2Elemental carbonSpecial attention to traffic exposure, incense, cottage industries (street food), tobacco smokeParallel monitoring at fixed site monitors for comparison of personal vs. ambient concentrations
20Are the poor more exposed? Personal PM 2.5 Exposures, by District and SES**Results of first 6 household visits
21How do exposures of the poor and non-poor correlate with the ambient air quality data?
22Intended Implications for Policy and Health Impact Assessment Global contribution:development of approaches to explore the relationship among air pollution, poverty, and healthaddress key scientific questions: higher exposures, different pollutant mixtures, climatic conditions, and disease distributionsRegional contribution:locally relevant base of air pollution and health sciencefocus on ALRI, a ‘disease of poverty’ responsible for a substantial burden of disease in childrenincreased local capacity for future research
23HCMC well equipped to conduct future research on health effects of air pollution Targeted technical assistance: training on study design, data management, statistical analysisNecessary infrastructure for personal exposure assessment (monitoring and analysis)Personal exposure monitoringPM and elemental carbon (gravimetric samples)NO/NO2 (passive samples)Exposure Assessment laboratory (controlled temperature, relative humidity, glove box, microbalance, reflectometer, ion chromatography unit)
25What 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 alreadyWill 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 susceptibilityHow can targeted monitoring be used to characterize and estimate exposure misclassification in routinely collected data?
26Thank you! Sumi Mehta - firstname.lastname@example.org Vu Xuan Dan -