2014 Progress Report: Quantifying the Climate, Air Quality and Health Benefits of Improved Cookstoves: An Integrated Laboratory, Field and Modeling Study

EPA Grant Number: R835438
Title: Quantifying the Climate, Air Quality and Health Benefits of Improved Cookstoves: An Integrated Laboratory, Field and Modeling Study
Investigators: Volckens, John , DeFoort, Morgan , Peel, Jennifer , Pierce, Jeffrey , Robinson, Allen
Current Investigators: Volckens, John , Johnson, Michael , Peel, Jennifer , Pierce, Jeffrey , Robinson, Allen
Institution: Colorado State University , Carnegie Mellon University
Current Institution: Colorado State University , Berkeley Air Monitoring Group , Carnegie Mellon University
EPA Project Officer: Keating, Terry
Project Period: September 1, 2013 through August 31, 2016 (Extended to August 31, 2017)
Project Period Covered by this Report: September 1, 2013 through January 27,2015
Project Amount: $1,520,000
RFA: Measurements and Modeling for Quantifying Air Quality and Climatic Impacts of Residential Biomass or Coal Combustion for Cooking, Heating, and Lighting (2012) RFA Text |  Recipients Lists
Research Category: Air Quality and Air Toxics , Global Climate Change , Tribal Environmental Health Research , Climate Change , Air

Progress Summary:

Objective 1: Development of a Global Cookstove Emissions Dataset

Laboratory Work. In August of 2014, the research team led a 15-day comprehensive testing campaign to develop a comprehensive data set on cookstove emissions (aka, the 2014 Front Range Cookstove Study). The 15-day intensive campaign was operated across three separate emission hoods, completed a total of 70 emissions tests, and included 15 different stove types and 7 different fuel types (approximately 25 stove/fuel combinations). Cookstoves were tested using a newly developed method: the firepower sweep protocol. The firepower sweep protocol was developed at Colorado State University (CSU) as an alternative to the "water boil test" to capture a broader range of cookstove operating conditions. Based on preliminary data analysis, we anticipate the firepower sweep test method will result in more comprehensive characterization of cookstoves while simultaneously being more representative of in-field cookstove use. An extensive suite of real-time and integrated instrumentation were used during the study that included: 5-Gas Analyzer/Testo (CO2, CO), Gravimetric Teflon Filters (particulate matter), Transmissometer (black carbon), Photoacoustic Exinctiometer (black carbon, scattering, absorption), Single Particle Soot Photometer (black carbon), Dust Track (particulate matter), Scanning Mobility Particle Sizer (particle size distribution), Aethalometer (black carbon), Soot Particle Aerosol Mass Spectrometer (black carbon composition) and a Continuous Ambient Particulate TEOM Monitor (particulate matter). We anticipate that the data set collected will allow us to better understand how parameters such as firepower, modified combustion efficiency and air fuel ratio can be used to predict emissions. 
 
A major finding of the Front Range Cookstove Study was that cookstove gas and particle emissions vary strongly with cookstove operating condition, as hypothesized.
 
A portable sampler has been built to characterize combustion emissions from residential cookstoves operated in the field. The sampler is capable of real-time PM2.5 measurements that include black carbon, mass concentration as well as nano-sized 1-minute size distributions from 10 – 400 nm. The sampler measures real-time gas concentrations of carbon monoxide (CO), carbon dioxide (CO2), oxygen (O2), sulfur dioxide (SO2) and volatile organic compounds (VOCs). Continuous measurements of relative humidity both from the exhaust and ambient are made along with ambient temperature and pressure. The sampler is also configured for filter collection allowing for offline analysis of mass emissions, organic and elemental carbon concentrations for an emissions event. All components are battery powered allowing for remote sampling without electricity. The portable sampler has been tested both at the Carnegie Mellon University (CMU) smog chamber lab, and the CSU combustion lab. Evaluation tests were performed in unison with a suite of standard lab instrumentation while sampling from a variety of cook stoves and fuels. 
 
The portable sampler showed good agreement when compared with lab-instrument measurements of PM, black carbon, gases, and aerosol size distributions. 
 
Field Work. The first of four field campaigns (designed to capture real-world cookstove emissions data) was conducted in January 2015, in Dong Wei, China, a peri-urban community approximately 100 km south of Beijing. The primary aim of this campaign was to characterize emissions performance and usage profiles of coal-based stoves, with a supplemental effort to assess indoor air quality and personal exposures for typical users. The team was supported locally partners from the Department of Building Science, Tsinghua University. The portable emissions sampler was used in 11 homes (eight coal and three biomass) to comprehensively characterize cookstove emissions, providing over 65 hours of data. Emissions were measured continuously in each household with the intent of capturing a full use cycle. Normal daily use activities were dominated by home heating tasks, although about half of the stoves were also used to heat water for drinking and supplemental cooking needs. Flue gas temperatures were also measured for approximately two weeks in the homes where the intensive emission sampling was conducted. This data will provide an estimate of typical daily firepower cycles. Finally, surface temperature loggers were installed on the stoves’ chimneys, as well as in an additional 26 homes to provide a larger, more representative sample of stove usage patterns. These loggers will record stove temperature through the middle of February to provide one month of stove usage data. Indoor air quality and personal exposure to PM2.5 and CO was measured in seven homes. Analysis of filters samples (gravimetric and thermal-optical) and processing of real-time data from the field campaign is currently underway. A structured review of the techniques and approaches used during this campaign are also being conducted to ensure that the lessons learned from this field campaign are translated into practical improvements for the future field campaigns.
 

Objective 2. Global Climate Modeling 

 
One of the goals of our project was to estimate the impact of cookstove emissions on climate. As the first step of this process, we estimated the uncertainty in climate forcings due to uncertainties in biofuel aerosol emissions. We used the global chemical transport model with online aerosol microphysics, GEOS-Chem-TOMAS, to study the sensitivity of the direct radiative effect (DRE) and cloud albedo indirect aerosol effect (AIE) to uncertainties in biofuel emission factors and model processes. 
 
In general, we find the DRE is strongly dependent on emission composition and optical properties, whereas the AIE is dependent on emission size distribution. The global annually averaged DRE ranges from -0.008 to +0.021 W m-2 just from altering mixing state. We find the global-mean direct radiative effect of biofuel emissions ranges from -0.02 to +0.06 W m-2 across all simulation/mixing state combinations with regional forcings in source regions ranging from -0.2 to +1.2 W m-2. The global mean cloud-albedo aerosol indirect effect ranges from +0.01 to -0.02 W m-2 with regional forcings in source regions ranging from -1.0 to -0.05 W m-2. Note that the DRE and AIE ranges from positive to negative forcing due to uncertainties in emission factors and optical properties. 
 
Major findings from this work are that the climatic effects of biofuel aerosols are largely unconstrained in that the overall sign of the aerosol effects is unclear due to uncertainties in model inputs. To better understand the climate impact of particle emissions from biofuel combustion, we recommend field/lab measurements to narrow constraints on: (1) emission mass, (2) emission size distribution, (3) mixing state, and (4) BC to OA ratio.

Future Activities:

During the upcoming project period, we shall focus on the following objectives:
  1. Develop a model to predict cookstove aerosol emissions as a function of basic operating parameters: firepower, combustion efficiency, fuel type, stove type. Validate this model against laboratory and field emissions data.
  2. Complete photochemical aging experiments using the CMU smog chamber to examine secondary organic aerosol formation from stove emissions.
  3. Complete field campaigns in Honduras (Spring 2015) and Kenya (summer 2015).
  4. Revise and re-analyze climate forcing simulation models with updated data from the 2014 and 2015 measurement campaigns. 

References:

Bond, T. C., Bhardwaj, E., Dong, R., Jogani, R., Jung, S., Roden, C., Streets, D. G. and Trautmann, N. M.: Historical emissions of black and organic carbon aerosol from energy-related combustion, 1850-2000, Global Biogeochem. Cycles, 21(2), n/a–n/a, doi:10.1029/2006GB002840, 2007. 

Journal Articles:

No journal articles submitted with this report: View all 19 publications for this project

Supplemental Keywords:

Household air pollution, wood smoke, airborne particulate matter, air quality, radiative forcing, emissions, aerosol 

Progress and Final Reports:

Original Abstract
2015 Progress Report
2016 Progress Report