P-390 Abstract: Economic deprivation could increase the magnitude of air pollution-related health impacts because: 1) due to poorer nutrition, timely access to medical care, or other factors, the poor experience more health impact per unit pollution exposure and/or 2) the poor experience higher levels of air pollution. There have been few studies of the interaction between poverty and the health effects of air pollution conducted, and most have been in Western countries. In Asia, the composition and relative contribution of indoor and outdoor sources of exposure are likely to be very different, and the impacts of exposure - and the influence of economic deprivation on those impacts - may be greater. While the results from Western studies can only be extrapolated with considerable uncertainty, to date no studies have been conducted in many of the poorer Southeast Asian countries. An interdisciplinary team of local and international experts has been working to refine feasible approaches to assess the health impact of air pollution among the poor in Ho Chi Minh City (HCMC). HCMC has an established ambient air quality monitoring network, computerized records of admissions and financial status at the pediatric hospitals, and detailed databases on household socio-economic position. This presents a unique opportunity to understand how the data from ambient networks relate to health impacts (particularly around average annual PM10 levels of 64–99 μg/m3 observed from 2000–2003 in HCMC), and the extent of exposure error arising from the use of ambient monitoring site data in health impact assessments for different socio-economic groups. This presentation will describe the ongoing process of implementing scientifically sound approaches to assessing the relation among air pollution, poverty, and health. Envisioned are: 1) a study of the effects of short-term exposure to air pollution on hospital admissions for acute lower respiratory infections (ALRI) in young children (<5 years) that compares the magnitude of the effect of air pollution on poor children versus other children and 2) a detailed characterization of exposures of the poor to air pollution from multiple sources. Proposed methods and the scientific rationale behind the choice of methods will be discussed, with a focus on the challenges of developing and testing hypotheses of the influence of socio-economic position on exposure and health, including methods to address potential sources of bias.