Grantee Research Project Results

Real-Time Monitoring of Individual Atmospheric Aerosol Particles: Establishing Correlations Between Particle Size and Chemical Speciation

EPA Grant Number: R826240
Title: Real-Time Monitoring of Individual Atmospheric Aerosol Particles: Establishing Correlations Between Particle Size and Chemical Speciation
Investigators: Prather, Kimberly A.
Institution: University of California - Riverside
EPA Project Officer: Hahn, Intaek
Project Period: February 1, 1998 through January 31, 2001
Project Amount: $547,000
RFA: Ambient Air Quality (1997) RFA Text | Recipients Lists
Research Category: Air Quality and Air Toxics , Air

Description:

Information on real-time variations of atmospheric aerosols is essential to developing appropriate control strategies and designing relevant health effect studies for particulates. Information from previous aerosol studies is limited by the long sampling times inherently required for off-line chemical analysis. The goal of the proposed research is to monitor changes in the particle size and chemical speciation of individual atmospheric aerosol particles over relatively short time intervals. Correlations will be established between fluctuations in aerosol particle size/composition distributions, gas phase measurements (i.e. NOx, ozone, NH3, HNO3), and meteorological conditions (wind speed, direction, relative humidity, temperature).

Approach:

The proposed studies will involve using a unique aerosol analysis method developed in our laboratory, aerosol time-of-flight mass spectrometry (ATOFMS), to monitor real-time variations in the size and chemical composition of individual aerosol particles. ATOFMS is currently the only real-time analysis method capable of providing precise aerodynamic size (+/- 1%) and correlated chemical composition information on polydisperse aerosol samples. Standard commercial gas phase measurement equipment and a weather station will be used for simultaneously measuring ozone and NOx concentrations and meteorological conditions. Denuder sampling and wet chemical analysis methods will be used for the analysis of various gas phase species.

Expected Results:

Recently, we demonstrated how ATOFMS can be used to obtain compositionally-resolved particle size distributions for atmospheric aerosols. The goal of the proposed research will be to establish how such distributions evolve over time for particles in the fine and coarse size modes (0.1-10 microns). Depending on atmospheric particle concentrations, between 2 and 10 particles per second can be analyzed using ATOFMS, thus providing representative real-time "snap-shots" of atmospheric aerosol size and chemical speciation over time intervals of several minutes. Using these real-time measurement capabilities, we will characterize temporal and spatial variations of atmospheric aerosol particles. These variations will be correlated with gas phase species concentrations, time of day, and meteorological conditions, leading to the first data detailing temporal variations in the size and chemical speciation of individual atmospheric aerosol particles.

Publications and Presentations:

Publications have been submitted on this project: View all 23 publications for this project

Journal Articles:

Journal Articles have been submitted on this project: View all 5 journal articles for this project

Supplemental Keywords:

ambient air, atmosphere, environmental chemistry, analytical, measurement methods, pollution, aerosol, source allocation, real-time, chemical analysis., RFA, Scientific Discipline, Air, particulate matter, Environmental Chemistry, tropospheric ozone, Ecology and Ecosystems, Environmental Monitoring, air sampling, ambient aerosol, chemical characteristics, particle size, aerosol time-of-flight mass spectrometry (ATOFMS), real time monitoring, atmospheric transport, chemical composition, chemical speciation sampling, particle transport, air pollution, ambient pollution control, fine particle formation, ambient measurement methods, aerosol sampling

Progress and Final Reports:

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.