Particulate Matter in California: Part 1―Intercomparison of Several PM_(2.5), PM_(10-2.5), and PM_(10) Monitoring Networks

摘要

It will be many years before the recently deployed network of fine particulate matter with an aerodynamic diameter less than 2.5 μm (PM_(2.5)) Federal Reference Method (FRM) samplers produces information on nonattainment areas, trends, and source impacts. However, data on PM_(2.5) and its major constituents have been routinely collected in California for the past 20 years. The California Air Resources Board operated as many as 20 dichotomous (dichot) samplers for PM_(2.5) and coarse PM (PM_(10-2.5)). The California Acid Deposition Monitoring Program (CADMP) collected 12-h-average PM_(2.5) and PM_(10) from 1988 to 1995 at ten urban and rural sites and 24-h-average PM_(2.5) at five urban sites since 1995. Beginning in 1994, the Children's Health Study collected 2-week averages of PM_(2.5) in 12 communities in southern California using the Two-Week Sampler (TWS). Comparisons of collocated samples establish relationships between the dichot, CADMP, and TWS samplers and the 82-site network of PM_(2.5) FRM samplers deployed since 1999 in California. PM mass data from the different monitoring programs have modest to high correlation to FRM mass data, fairly small systematic biases and negative proportional biases ranging from 7 to 22%. If the biases are taken into account, all of the programs should be considered comparable with the FRM program. Thus, historical data can be used to develop long-term PM trends in California.