Abstract

There is evidence that air quality on a global scale is threatened by the systematic change in the atmospheric concentration of a variety of trace compounds. These compounds range from those that are not chemically reactive in the lower atmosphere (troposphere), such as the chlorofluoromethanes (CFM), to very reactive compounds, such as the oxides of nitrogen (NO_x) and the nonmethane hydrocarbons (NMHC). Although all the compounds cause significant problems concerning air quality on a regional or even global scale, the type of data required to obtain the necessary information concerning their atmospheric distribution depends strongly on the chemical reactivity (lifetime) of the compounds in the atmosphere. To monitor the concentrations of and understand the processes involving these compounds, very sensitive and/or precise measurement techniques are required. Specifically, these techniques may be required to detect less than one part per billion of the compound of interest or have a precision of one part in 10⁴. The air quality problems associated with these compounds are outlined and the instrument needs and requirements for the measurement of the compounds are briefly discussed. Finally, the current approach to the validation of measurement techniques is described.

© 1989 Optical Society of America