ASSESSING PARTICULATE MATTER AND BLACK CARBON EMISSIONS FROM HOMES USING TRADITIONAL AND ALTERNATIVE COOKSTOVES IN RURAL NEPAL

Black carbon;air pollution;climate change;Indo-Gangetic Plain;Public Health Studies

Soneja, SutyajeetTielsch, James M. ;

Johns Hopkins University

关键词: Black carbon;    air pollution;    climate change;    Indo-Gangetic Plain;    Public Health Studies;   

Others  :  https://jscholarship.library.jhu.edu/bitstream/handle/1774.2/37892/SONEJA-DISSERTATION-2014.pdf?sequence=1&isAllowed=y

瑞士|英语

来源: JOHNS HOPKINS DSpace Repository

【 摘 要 】

Billions of people throughout the developing world use traditional cookstoves fueled with biomass (such as wood, dried animal manure, and crop residue). Inefficient combustion of biomass results in the formation of large amounts of particulate matter (PM) air pollution. Light reflecting black carbon is a significant component of this PM. Black carbon is considered a short-term climate agent with an average atmospheric residence time on the order of days to weeks, compared to some greenhouse gases that can have an atmospheric residence time of years to centuries. In addition to having an effect on regional hydrological cycles, black carbon deposition on glaciers, sea, or land ice causes a decrease in surface albedo, thus resulting in an acceleration of the melting process. The Himalayas, an area containing the largest snow and ice mass outside the North and South Poles, are vulnerable to black carbon deposition from highly prevalent biomass cooking in surrounding countries. Deposition of black carbon from air pollution has the potential to impact the availability of glaciers in this region, which act as a water source for close to a billion people throughout South and East Asia. As a result, due to the larger population, biomass for cooking in South Central Asia has the potential to impact climate change on a local and global scale.It is believed that a large majority of black carbon production in South Asia is a result of cooking with biomass fuels. However, biomass cooking is not the only source of black carbon. Mobile (diesel vehicles) and stationary (brick kilns) sources can also be significant emitters. This study estimates black carbon emissions associated with traditional and alternative cookstoves at the household level. This study can be further separated into three main components.The first component is a methods paper focusing on improved quality control for a commonly used particulate matter sampling method. Great uncertainty exists around indoor biomass burning exposure-disease relationships due to lack of detailed exposure data in large health outcome studies. Passive nephelometers can be used to estimate high particulate matter (PM) concentrations during cooking in low resource environments. Nephelometric concentration readings can be biased due to particle growth in high humid environments and differences in compositional and size dependent aerosol light scattering characteristics. Chapter 2 explores relative humidity (RH) and gravimetric equivalency adjustment approaches for the pDR-1000, which is used to assess indoor PM concentrations for a cookstove intervention trial in Nepal. Furthermore, new integrated RH and gravimetric conversion methods are presented because they have one response variable (gravimetric PM2.5 concentration), do not contain an RH threshold, and are more straightforward than previously proposed approaches.The second component focuses on characterizing the amount of particulate matter and black carbon that exit the house during the use of traditional, open-design cookstoves in village homes. Cookstove emissions create indoor exposures and contribute to ambient air pollution through passive exchanges between indoor and outdoor air (indirect venting) and direct venting (i.e., chimney) to the outdoors. A fraction of PM produced during cooking will settle and deposit on indoor surfaces as well as in cracks within the walls of the house, while the rest will escape to the outdoor environment (known as exfiltration). Currently, there is a poor understanding of how much cooking-related PM exfiltrates to the outdoor environment. Chapter 3 presents air exchange rates and PM exfiltration estimates from homes in rural Nepal that utilize traditional, open-design cookstoves. Estimates of variability are provided for exfiltration as a function of housing and fuel characteristics in a real-world setting. Furthermore, this chapter assesses the black carbon to PM2.5 ratio produced by biomass cooking in order to estimate black carbon exfiltration from homes. In combination with an assessment of indoor PM concentrations, PM and black carbon exfiltration fractions can be used to estimate house emissions to ambient air in order to better assess regional air quality and climate change impacts.The third component (Chapter 4) extends upon this work by presenting exfiltration estimates of PM that exit to the outdoors via the combined route of indirect (natural) and direct (chimney) ventilation for alternative cookstoves being studied in a large, cookstove intervention trial in rural Nepal. Characterizing these exfiltration pathways allows for homes to be treated as a source, hence aggregating variability related to stove emissions.Future work will utilize estimated black carbon emissions in combination with estimates of cookstove use and cooking pattern estimates to serve as inputs for spatial regression modeling that will allow for the prediction of ground level black carbon concentrations across much of Northern India and Southern Nepal (the Indo-Gangetic Plain). Since a large fraction of the world’s biomass cookstove users are in South Central Asia, this project provides significant insight of cookstove emission to atmospheric contribution.