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Grantee Research Project Results

Grantee Research Project Results

Development of Methods for Measuring Carbon Particles in Precipitation and Determination of Wet Removal Rates

EPA Grant Number: FP917370
Title: Development of Methods for Measuring Carbon Particles in Precipitation and Determination of Wet Removal Rates
Investigators: Torres-Negron, Alexander
Institution: University of Illinois at Urbana-Champaign
EPA Project Officer: Just, Theodore J.
Project Period: August 1, 2011 through July 31, 2014
Project Amount: $126,000
RFA: STAR Graduate Fellowships (2011)
Research Category: Academic Fellowships , Fellowship - Clean Air



Current understanding of the atmospheric cycle of carbon aerosols is poorly understood still because their removal rate by wet deposition has not been studied meticulously. This research project will measure the concentrations of organic and black carbon in precipitation, and match them with their respective atmospheric concentrations at a specific site, yielding insight into aerosol removal from the atmosphere. This study also will provide a record of carbon particle concentration in precipitation at multiple sites that can be used to evaluate the removal predictions by atmospheric models. This database will be an important contribution to the scientific community for the accurate determination of the effects of carbonaceous aerosols on human health, visibility and climate change.


The first stage of this research is to develop an analytical method for measuring organic carbon and black carbon in precipitation. The TOC Analyzer will be used to measure dissolved organic carbon, and the OC/EC Analyzer (Thermal- Optical Analysis) will be used to measure particulate organic carbon and black carbon. Laboratory standards made from carbon aerosols generated in the laboratory will be used to evaluate the efficiency of the analytical method. In the second stage of the research, the developed method will be used to measure the concentration of carbon particles in precipitation. Rain samples will be collected during one year in the Bondville Environmental and Atmospheric Research Station at Bondville, Illinois. The concentrations of carbon particles in rainwater will be matched with the concentration of carbon aerosols in the atmosphere, measured by the Interagency Monitoring of Protected Visual Environments (IMPROVE) monitoring program. Precipitation sampling will be extended to some other monitoring stations within the National Atmospheric Deposition Program (NADP) to increase the spatial distribution of the measurements. The database of carbon aerosol concentration in rain will be used to determine the scavenging coefficients of the individual species of carbon aerosols. In addition, back trajectory modeling will be used to determine the dominant sources of carbon aerosols in the region.

Expected Results:

At the end of this research, it is expected to define and recommend an analytical procedure for measuring carbon in rainwater that can be used with confidence by other researchers. A dataset of carbon particle concentration in rain, matched with atmospheric concentrations, will be created. Carbon concentration in rain also will be correlated with major ions and elements in rain, helping to understand the principles that lead the removal by wet deposition. The inclusion of multiple monitoring sites will aid to evaluate the removal rates at different regions and times. This area and time distribution of concentration will help to identify the major sources and distances that carbon particles are transported before being removed from the atmosphere by wet deposition.

Potential to Further Environmental / Human Health Protection

This research project will yield insight into the removal rate of carbonaceous aerosols from the atmosphere by precipitation, and will identify the processes that affect the wet scavenging. This information is necessary to improve the fidelity of models used to assess the impacts of carbonaceous aerosols on human health, visibility and climate change.

Supplemental Keywords:

wet deposition, wet scavenging, organic carbon, black carbon, elemental carbon, air quality, climate change, air pollution, atmosphere, precipitation, rain,

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The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.

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