Air quality measurements—From rubber bands to tapping the rainbow

ABSTRACT

It is axiomatic that good measurements are integral to good public policy for environmental protection. The generalized term for “measurements” includes sampling and quantitation, data integrity, documentation, network design, sponsorship, operations, archiving, and accessing for applications. Each of these components has evolved and advanced over the last 200 years as knowledge of atmospheric chemistry and physics has matured. Air quality was first detected by what people could see and smell in contaminated air. Gaseous pollutants were found to react with certain materials or chemicals, changing the color of dissolved reagents such that their light absorption at selected wavelengths could be related to both the pollutant chemistry and its concentration. Airborne particles have challenged the development of a variety of sensory devices and laboratory assays for characterization of their enormous range of physical and chemical properties. Advanced electronics made possible the sampling, concentration, and detection of gases and particles, both in situ and in laboratory analysis of collected samples. Accurate and precise measurements by these methods have made possible advanced air quality management practices that led to decreasing concentrations over time. New technologies are leading to smaller and cheaper measurement systems that can further expand and enhance current air pollution monitoring networks.

Implications: Ambient air quality measurement systems have a large influence on air quality management by determining compliance, tracking trends, elucidating pollutant transport and transformation, and relating concentrations to adverse effects. These systems consist of more than just instrumentation, and involve extensive support efforts for siting, maintenance, calibration, auditing, data validation, data management and access, and data interpretation. These requirements have largely been attained for criteria pollutants regulated by National Ambient Air Quality Standards, but they are rarely attained for nonroutine measurements and research studies.

Acknowledgment

Acknowledgement is expressed here to our many colleagues for their contributions to measurement technologies over the years, without whom the current state of the art would be far behind in its evolution; and to our sponsors of monitoring and field research whose major investment made possible the sustained effort to characterize air chemistry and its potential for exposure risk to the public and to our neighboring ecosystems. The authors appreciate the comments and suggestions of John Bachmann, retired from the U.S. Environmental Protection Agency, for improving the initial draft of this article.

Additional information

Notes on contributors

George M. Hidy

The authors are long-term members of the Air & Waste Management Association (A&WMA) and its Critical Review and Publication Committees, and have made many contributions to the Journal of the Air & Waste Management Association (JA&WMA), EM Magazine, annual meetings, and specialty conferences.

Dr. George M. Hidy currently is a principal of Envair/Aerochem, a former co-editor of JA&WMA, a former chair of the Critical Review Committee, and author of the 1984 and 2010 A&WMA Critical Reviews.

Peter K. Mueller

Dr. Peter K. Mueller is a principal of Tropochem and the longest continuing member of A&WMA (65 years).

Samuel L. Altshuler

Samuel L. Altshuler is an air quality consultant and former member of the Bay Area Air Quality Management District advisory board.

Judith C. Chow

Dr. Judith C. Chow is a research professor at the Desert Research Institute, a former chair of the Critical Review Committee, and author of the 1995 A&WMA Critical Review.

John G. Watson

Dr. John G. Watson is a research professor at the Desert Research Institute, a former chair of the Critical Review Committee, and author of the 2002 A&WMA Critical Review.