Climate and health impacts of particulate matter from residential combustion sources in developing countries
Date
2018
Authors
Kodros, John K., author
Pierce, Jeffrey R., advisor
Volckens, John, committee member
Kreidenweis, Sonia, committee member
Ravishankara, A. R., committee member
Journal Title
Journal ISSN
Volume Title
Abstract
Globally, close to 2.8 billion people lack access to clean cooking technology, while 1.8 billion people lack access to electricity altogether. As a means to generate energy for residential tasks, it is common in many developing countries to rely on combustion of solid fuels (wood, dung, charcoal, trash, etc.). Solid fuel use (SFU) can emit substantial amounts of fine particulate matter (PM2.5), often in or in close proximity to residences, creating concerns for human health and climate; however, large uncertainties exist in indoor and outdoor concentrations and properties, limiting our ability to estimate these climate and health impacts. This work explores the uncertainty space in estimates of premature mortality attributed to exposure to PM2.5 from residential SFU (e.g., cooking, heating, lighting) and makes the first estimates of health and radiative effects from combustion of domestic waste (i.e., trash burning). Next, we investigate key uncertain parameters (emission size distribution, black carbon mixing state, and size-resolved respiratory deposition) that drive uncertainties in health and radiative impacts from SFU, in order to improve model estimates of aerosol impacts from all sources. In many developing regions, combustion of solid fuels for cooking and heating is not the only aerosol source impacting air quality and climate. While uncontrolled combustion of domestic waste has been observed in many countries, this aerosol source is not generally included in many global emissions inventories. Using a global chemical-transport model, we estimate exposure to ambient PM2.5 from domestic-waste combustion to cause 270,000 (5th-95th percentile: 213,000 to 328,000) adult mortalities per year, most of which occur in developing countries. Regarding aerosol radiative effects, we estimate the globally averaged direct radiative effect (DRE) to range from -40 mW m-2 to +4 mW m-2 and the aerosol indirect effect (AIE) to range from -4 mW m-2 to -49 mW m-2. In some regions with significant waste combustion, such as India and China, the aerosol radiative effects exceed −0.4 W m−2.The sign and magnitude of the global-mean DRE is strongly sensitive to assumptions on how black carbon (BC) is mixed with scattering particles, while the AIE is strongly sensitive to the emission size distribution. To determine what factors dominate the uncertainty space in mortality estimates from SFU, we perform a variance-based sensitivity analysis on premature mortality attributed to the combined exposure to ambient and household PM2.5 from SFU. We find that uncertainty in the percent of the population using solid fuels for energy contributes the most to the uncertainty in mortality (53-56% of uncertainty across Asia and South America) with the concentration-response function the next largest contributor (40-50%). In the second half of this dissertation, we explore several key uncertainties in climate and health estimates of aerosol from residential sources in order to reduce overall model uncertainty of aerosol impacts from any source. To test the sensitivity of the AIE to treatment of aerosol size distributions in global models, we estimate the AIE due to anthropogenic emissions with prognostic sectional aerosol microphysics and compare this to the AIE calculated when the simulated aerosol mass of each species is remapped onto a prescribed size distribution. Simulations using the prognostic scheme yield a global mean anthropogenic AIE of −0.87 W m−2, while the simulations with the prescribed scheme predict −0.66 W m−2. These differences suggest that simulations with prescribed size‐distribution mapping are unable to capture regional and temporal variability in size‐resolved aerosol number and thus may lead to biases in estimates of the AIE.
Description
Rights Access
Subject
air pollution
environment
particulate matter
climate
aerosol
health