Evaluation of Cookstove Technologies in a Field Intervention Trial in Rural India:
General Material Designation
[Thesis]
First Statement of Responsibility
Islam, Mohammad Maksimul
Title Proper by Another Author
Quantifying Indoor Air Quality and Emissions Performance
Subsequent Statement of Responsibility
Menendez, Fernando Garcia
.PUBLICATION, DISTRIBUTION, ETC
Name of Publisher, Distributor, etc.
North Carolina State University
Date of Publication, Distribution, etc.
2021
PHYSICAL DESCRIPTION
Specific Material Designation and Extent of Item
291
DISSERTATION (THESIS) NOTE
Dissertation or thesis details and type of degree
Ph.D.
Body granting the degree
North Carolina State University
Text preceding or following the note
2021
SUMMARY OR ABSTRACT
Text of Note
Globally over 3 billion people use solid fuel cookstoves to meet household energy demand. Cookstove emissions lead to household and ambient air pollution, with adverse health and climate impacts. To reduce these harmful impacts, alternative cookstove technologies have been developed and promoted worldwide in diverse intervention programs. To evaluate the effectiveness of these programs, estimating the emission reduction potential of these stoves and assessing associated indoor air quality (IAQ) impacts are essential. This thesis presents analysis of data collected (by research collaborators) during a randomized control trial conducted in two rural locations in India with one baseline and two follow-up measurement periods. After the baseline, intervention households selected from multiple cookstove options ranging from improved biomass (rocket, gasifier) to liquefied petroleum gas (LPG) stoves, while control households used pre-existing traditional solid fuel (TSF) stoves throughout. This study included 253 stove emission tests, and 1205 days of indoor PM2.5 (fine particulate matter) concentration measurements. These large datasets were used to test several hypotheses, including: (a) emission reductions observed for alternative stoves, relative to TSF, in lab will be observed in end-user kitchens; (b) brown carbon (BrC) - a component of stove emissions - from real-world kitchens will be more light absorptive than lab; (c) IAQ in kitchens with the same stove will not consistently vary across measurement periods and locations; (d) improvement in IAQ will be greater in households with greater adoption of alternative stoves; (e) a single-compartment box model will overestimate observed PM2.5 concentrations in Indian kitchens. To explore these hypotheses, group-wise and paired comparisons, parametric and non-parametric statistical tests, and univariate and multivariate regressions were performed. During the trial, most households chose the LPG stove; few (<30%) selected an alternative biomass stove. Among the alternative biomass stoves tested, only a rocket stove showed moderate reductions in pollutant emission factors (EFs) relative to TSF. In contrast, LPG was associated with substantially lower emissions and household air pollution. However, emissions from some LPG tests were above the health-based guidelines, possibly due to simultaneous use of biomass stoves nearby or emissions from food and lamp/incense burning. TSF EFs varied somewhat between measurement periods but not across the study locations. In contrast, indoor PM2.5 during TSF use were consistently different in two locations, and higher in the location with longer daily cooking duration, lower air exchange rate and smaller kitchen wall openings. This suggests that cooking practice and kitchen ventilation characteristics played important roles in driving IAQ variability across households and communities. Kitchen chimneys - present in some households in one study location - appeared as an important factor in improving IAQ. In the other location, an improved chimney stove was also associated with substantially lower indoor PM2.5 relative to basic chimney stove. However, PM2.5 EFs from these two stove types were not different, indicating that chimney function or condition was likely the factor improving IAQ. A single box model used to set WHO emission rate targets provided approximately an order of magnitude overestimation of kitchen PM2.5 across a range of biomass stove models. Some factors were identified influencing model performance (e.g. kitchen volume, aspect ratio, air exchange rate, indoor temperature and PM level), which can be incorporated in future research to refine model performance. BrC, extracted from field emission samples of stoves, was less light absorptive than that from lab, but fell in a continuum of combustion sources identified in other work. Simple modeling to estimate radiative forcing of aerosols showed that BrC was associated with a shift from cooling to warming, implying that BrC should be treated as a major player along with black carbon determining the climate effects of this large emission source.