Measurements in support of air quality improvement—some historical insights

A brief historical summary of developments in a select few areas of atmospheric measurements is given to illustrate how they have led to an improvement in our ability to effect meaningful, effective control strategies by improving our knowledge of the atmospheric chemistry of trace gases and particles. Conversely, some examples will also be given of how measurement deficiencies led to misleading conclusions concerning the nature and extent of environmental pollution, and permitted the development of ineffective control strategies. Measurement artifacts for prominent particulate constituents—sulfate, nitrate and organic species—are discussed, focusing on key measurement principles that were developed to overcome those artifacts. The use of tracers and source apportionment techniques to quantify the contributions of sources of pollutants and their precursors is another example of measurement science enabling effective control strategies. The intent of this paper is to illustrate how better measurement science leads to more accurate assessment of pollutant formation and transport processes, and hence to the development of more effective pollutant control strategies.