2009 Progress Report: Improved Treatment of Atmospheric Organic Particulate Matter Concentrations from Biomass Combustion EmissionsEPA Grant Number: R833747
Title: Improved Treatment of Atmospheric Organic Particulate Matter Concentrations from Biomass Combustion Emissions
Investigators: Kreidenweis, Sonia M. , Collett Jr., Jeffrey L. , Hao, Wei Min , Heald, Colette L. , Jimenez, Jose-Luis , Kroll, Jesse H. , Onasch, T. , Trimborn, Achim , Worsnop, Douglas R.
Institution: Colorado State University , Aerodyne Research Inc. , Fire Sciences Laboratory, Rocky Mountain Research Station , University of Colorado at Boulder
Current Institution: Colorado State University , Aerodyne Research Inc. , Fire Sciences Laboratory, Rocky Mountain Research Station
EPA Project Officer: Chung, Serena
Project Period: September 1, 2007 through December 31, 2010 (Extended to December 31, 2012)
Project Period Covered by this Report: January 1, 2009 through December 31,2009
Project Amount: $598,645
RFA: Sources and Atmospheric Formation of Organic Particulate Matter (2007) RFA Text | Recipients Lists
Research Category: Air Quality and Air Toxics , Particulate Matter , Air
We propose to measure, for the first time, volatility distributions, as functions of both dilution and temperature, of open biomass burning emissions for a variety of fuel types relevant to U.S. air quality. We propose to interpret data using semivolatile partitioning models, and to implement and test new biomass-burning emissions maps and partitioning models in large-scale model runs.
We have completed a series of experiments in which we generated open biomass burning emissions and subjected them to controlled dilution and thermal processing. We measured the response of the aerosol mass concentrations and speciation to this processing in order to develop a database that can be used to characterize the volatility of the combustion emissions. Our data analyses, currently in progress, will evaluate the gas / particulate partitioning of these emissions as a function of both dilution and temperature, and will also provide updated emission factors and volatility information for levoglucosan, a key biomass burning tracer. To date, we have completed preliminary data analyses that reveal a wide variation in the response of emissions from different fuels to isothermal dilution (~10x and ~100x, which we refer to as “low” and “high” dilution). In the accompanying figure, we summarize our preliminary estimates of these responses for seven tested fuels. The variable plotted on the y-axis is the ratio (observed dilution) / (expected dilution). If this ratio is equal to 1, then the emissions were essentially nonvolatile in our experiments; if the ratio is >1, as was clearly the case for three of fuels shown in the figure, the organic particulate matter evaporated significantly upon isothermal dilution, and should not be represented as nonvolatile primary particulate emissions in air quality models. Rather, these organic particulate emissions should be modeled as semivolatile, and the subsequent atmospheric fates of the evaporated organic species must be studied further so they can be accurately simulated.
The data from our studies will help improve models of biomass burning primary particulate emissions, including understanding how emissions vary during different burn phases. Improved representation of the role of biomass combustion in affecting ambient PM2.5 levels is expected to be a key contribution to improved understanding of the sources of atmospheric organic particulate matter, and its impacts on air quality and health.
Figure 1. Comparisons of measured / expected dilutions for the organic aerosol as measured by the AMS, for both high- and low-dilution isothermal exposures of aerosols produced in the combustion of the indicated fuels.
In Year 3, the final year of this project, we will complete analyses of our 2009 dilution experiments, emphasizing the HR-ToF-AMS and tracer measurements. In addition to preparing manuscripts on the findings from our rich data set, we will also fit the information to 2-product and volatility basis set frameworks. The compilation of these fits will be one of our key deliverables. The other major activity in Year 3 will be the modeling of the effects of our improved emissions representation on aerosol loadings during selected biomass burning events affecting the U.S. The modeling study will help elucidate the degree to which the treatment of emissions as semivolatile changes predicted aerosol concentrations.
Journal Articles on this Report : 2 Displayed | Download in RIS Format
|Other project views:||All 30 publications||23 publications in selected types||All 23 journal articles|
||Huffman JA, Docherty KS, Mohr C, Cubison MJ, Ulbrich IM, Ziemann PJ, Onasch TB, Jimenez JL. Chemically-resolved volatility measurements of organic aerosol from different sources. Environmental Science & Technology 2009;43(14):5351-5357.||
||Lee T, Sullivan AP, Mack L, Jimenez JL, Kreidenweis SM, Onasch TB, Worsnop DR, Malm W, Wold CE, Hao WM, Collett Jr. JL. Chemical smoke marker emissions during flaming and smoldering phases of laboratory open burning of wildland fuels. Aerosol Science and Technology 2010;44(9):i-v.||