“Indoor Air Pollution” Framing Issues.ppt

“Indoor Air Pollution”Framing Issues Risk Factor Exposure Outcomes Background Disease Counterfactual Risk Factor Household solid fuel use Clearly polluting in nearly all settings Available in household surveys Most common metric in epi studies Expands risk boundary Portion of outdoor air pollution Burns Other non-air-pollution pathways, e.g. risks of gathering biomass fuel and coal mining -? Even a portion of climate change due to household fuels-? Include high-income countries where much wood is used in households, but not for cooking-? Difficulties of Household Solid Fuel Use as RF Exposures are not uniform because Coal and biomass are different Amount of usage usually not known Difficulty of separating cooking from the heating often done in non-tropical settings Chimneys dominate in richer countries and are found in poor ones – effectiveness variable Location of cooking in household not uniform, which affects exposure A set of the major interventions being explored are low-emissions biomass stoves Exposure Few studies used direct exposure assessment, i.e., average air pollution concentration affecting people, which roughly corresponds to annual means used in outdoor air pollution studies Reviews of health effects need to capture a wide range of indicators of exposures, incl: Solid fuel vs. another (cleaner) fuel Time spent near stove Duration of exposure (years) to solid fuels Separate kitchen from main house Improved vs. Traditional stove How to combine? And do so in a way consistent with available household fuel inventories Outcome Measures A growing number of outcomes are associated with exposures Some have dozens of epi studies, i.e. ALRI, COPD, lung cancer from coal – outcomes from CRA-2000 Some have less than 10 with consistent results, i.e., LBW and cataracts Some have less than 10 with some inconsistency, i.e., TB, lung cancer from biomass Some have few studies but would be expected from other pollution exposures (outdoor air, ETS, and smoking), i