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Project at a Glance

Title: Spatial and temporal characterization of fine particulate matter mass concentrations in California, 1980-2002.

Principal Investigator / Author(s): Blanchard, Charles L

Contractor: Envair

Contract Number: 03-350

Research Program Area: Atmospheric Processes

Topic Areas: Monitoring


Studies of fine particulate matter (PM) levels, trends, and effects in California need a reliable long-term record of ambient fine PM mass concentrations. Systematic measurement of fine PM mass concentrations began nationally with implementation of the Federal Reference Method (FRM) network in 1998 and 1999. However, a variety of other monitoring networks have measured fine PM mass concentrations, other PM size fractions, and related pollutants during various periods of time and at varying numbers of sites in California from 1980 through 2002. We developed an historical record of fine PM mass concentrations by combining data from different monitoring programs, accounting for differences in measurement methods and accuracy. The product of this work is a database consisting of estimates of monthly-average fine PM mass concentrations and their uncertainties at monitoring sites in California for the period from 1980 through 2002.

We investigated the comparability of PM2.5 mass concentration measurements from different monitoring networks, reconstructed FRM-equivalent PM2.5 mass concentrations from other types of measurements, and estimated the associated uncertainties. We established conversion factors to standardize fine mass measurements from other network to FRM equivalents. The other networks include the California Air Resources Board (CARB) dichotomous sampler network and a variety of special studies conducted prior to implementation of the FRM network.

Where alternative measurements of fine PM mass were not available, we reconstructed fine mass from PM components measured in other size fractions, light absorption, or light scattering.


For questions regarding this research project, including available data and progress status, contact: Heather Choi at (916) 322-3893

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