New NIST Database Will Help Assess Air Quality

A new database now available from the Commerce Department's National Institute of Standards and Technology will help measure airborne pollutants from manufacturing plants or other sources with greater accuracy.

The new NIST Quantitative Infrared Database has been designed to calibrate and verify measurements made with infrared-based analytical instruments in field- monitoring of hazardous air pollutants identified by the U.S. Environmental Protection Agency. The new database, available on CD-ROM, is also the first issued by NIST that can be used to establish traceability to NIST's primary gas standards. A team of NIST scientists created the database in response to a request from the EPA.

"This database is a major step toward providing the critically evaluated reference data required for optical instruments to become accurate and cost-effective tools for measuring levels of hazardous air pollutants," says Pamela Chu, a chemist in the NIST Analytical Chemistry Division and database project leader.

While the database program was established initially to verify the accuracy of emissions monitoring, it has a broad base of possible applications such as monitoring chlorofluorocarbon gases in semiconductor manufacturing, measuring the components of natural gas and detecting gaseous chemical weapons.

In recent years, scientists have developed analytical methods and instruments that make it possible to monitor air pollution on site. Older methods require chemists to trap air samples in or near a smokestack and transport them to a lab for analysis. In addition to being time consuming, such methods were prone to sample contamination. A new method, based on Fourier transform infrared (FT-IR) spectroscopy, has the advantage of being fast and convenient but, until now, has lacked reliable standards. New EPA methods allow monitoring with FT-IR instruments for the hazardous air pollutants listed in the 1990 Clean Air Act amendments.

NIST scientists accurately measured and assessed the uncertainty of the infrared spectra for 21 volatile organic compounds identified as high priorities by the EPA. The measurements were made on primary gas standards prepared and verified at NIST. In the future, researchers will expand and update the database to contain about 100 of the 189 compounds listed in the Clean Air Act amendments.

The database includes programs to allow viewing, printing and verifying the spectra. The database also employs data authentication to assure users that spectral files are unaltered and traceable to NIST. The Quantitative Infrared Database, or NIST Standard Reference Database 79, is available from the NIST Standard Reference Data Program for $240. It runs on a Windows 95, Windows 98 or Windows NT operating system. Updates will be available over the Internet. For more information on the database, go to www.gases.nist.gov on the World Wide Web.

To order, contact the NIST Standard Reference Data Program, 100 Bureau Drive, Stop 2310, Gaithersburg, Md. 20899-2310; (301) 975-2208; fax: (301) 926-0416; srdata [at] nist.gov (srdata[at]nist[dot]gov).

As a non-regulatory agency of the U.S. Department of Commerce’s Technology Administration, NIST strengthens the U.S. economy and improves the quality of life by working with industry to develop and apply technology, measurements and standards through four partnerships: the Manufacturing Extension Partnership, the Measurement and Standards Laboratories, the Advanced Technology Program, and the Baldrige National Quality Program.