SRMs for Contaminants in Air Particulate Matter

In 1997 the U.S. Environmental Protection Agency (EPA) issued new standards for air particulate matter (PM) as part of the national ambient air quality standards, including new regulations for PM less than 2.5 μm (PM2.5), which is the respirable PM fraction, in addition to the existing PM10 standards. To support compositional analyses and other investigations on the fine PM, quality assurance materials are necessary. NIST has collaborated with the EPA to develop SRMs to support measurements of organic species in fine PM while continuing research on the composition of bulk PM, renewing SRM 1648a Urban Particulate Matter and SRM 1649b Urban Dust.

The development of SRMs to support measurements for organic species in fine PM will expand quality assurance capabilities to important source markers and species critical to human health. Replenishment of the supply of bulk PM will extend NIST’s support for organic and inorganic characterization of aerosols for many years. Users can relay on their experience with SRM 1648a and SRM 1649b and can refer to extensive literature resources on both materials.

The renewals of two bulk PM SRMs, SRM 1648a Urban Particulate Matter and SRM 1649b Urban Dust, are completed, and the certification measurements for SRM 2786 Fine Urban Particulate Matter (<4 μm) and SRM 2787 Fine Urban Particulate Matter (<10 μm) are underway. The data from multiple independent analytical methods have been combined to certify the concentrations of 24 elements in SRM 1648a and 23 polycyclic aromatic hydrocarbons (PAHs), 13 polychlorinated biphenyl (PCB) congeners, and 4 chlorinated pesticides in SRM 1649b. Concentration values for additional elements and organic constituents are available on the Certificates of Analysis as reference values. Similar independent analytical methods are being applied to the analysis of SRM 2786 and SRM 2787 to provide both element and organic composition data on the Certificates of Analysis.

Major Accomplishments:

• The renewals of two bulk PM SRMs, SRM 1648a and SRM 1649b, are completed providing new value assignments.    
• The certification measurements are underway for two fine PM SRMs, SRM 2786 and SRM 2787.