Grantee Research Project Results
Intra-Community Spatial Variation of Size-Fractionated PM and Source Apportionment Using Organic Compounds as Tracers
EPA Grant Number: F5D30805Title: Intra-Community Spatial Variation of Size-Fractionated PM and Source Apportionment Using Organic Compounds as Tracers
Investigators: Krudysz, Margaret A
Institution: University of California - Los Angeles
EPA Project Officer: Hahn, Intaek
Project Period: January 1, 2005 through December 31, 2006
Project Amount: $104,822
RFA: STAR Graduate Fellowships (2005) RFA Text | Recipients Lists
Research Category: Academic Fellowships
Objective:
The objectives of this research project are to
- investigate the spatial variation in ultrafine, accumulation, and coarse particulate matter (PM) mass and chemical composition;
- examine the spatial variation in PM-associated organics and quantitatively assess PM components in relation to various emission sources using organic compounds as tracers and chemical mass balance methods; and
- evaluate the accuracy of using central site monitors for estimating population exposure to PM. Ambient PM from different sources and in different size fractions have been associated with varying degrees of health impacts. In addition, high concentrations of ultrafine particles have been found near freeways implying that local traffic patterns and proximity to complex pollution sources are important in assessing PM exposure in urban communities. This study will evaluate particles sources and formation mechanisms, as well as their geographical and seasonal variability.
Approach:
Organic speciation and PM chemical content will be assessed on Long Beach summer and winter samples collected outside of residential homes, elementary schools, and central monitoring sites. Quantification of individual organic compounds will involve extraction with a mixture of methanol and dichloromethane after spiking with deuterated internal standards. Combined and concentrated extracts will be split into two parts. One fraction will be derivatized with diazomethane to convert organic acids to their methyl esters, and the other will remain underivatized. Both fractions, as well as authentic quantification standards with known amounts of the same isotope-labeled compounds used to spike the samples, will be analyzed by Gas Chromatography/Mass Spectrometry techniques. The organic tracers used in chemical mass balance analyses will include hopanes and steranes, heavy PAHs, levoglucosan, cholesterol, monoglycerides, crustal elements, di-acids, and other compounds.
Expected Results:
This project will provide essential information on the chemical composition of size-fractionated aerosols, and will allow for reconciliation of sources, which contribute to the high concentrations of particulate matter in southern California. These data is expected to reveal significant differences in the spatial and temporal concentrations of aerosol components and will, therefore, contribute to understanding of local pollution sources.