Comparison of Ultraviolet Absorbance, Chemiluminescence, and DOAS Instruments for Ambient Ozone Monitoring

Abstract

This paper evaluates the accuracy of ozone measurements made by monitors that determine ozone concentrations in ambient air by UV absorption. These monitors are typically used to measure ozone for the purpose of establishing local compliance to air-quality standards. The study was predicated by the concern that commercially available UV absorbance O 3 monitors may be subject to interference from volatile organic carbon (VOC) species that absorb light at 254 nm. To test for these and other effects, we compared simultaneous O 3 measurements made by a commercial UV O 3 monitor with an O 3 -NO chemiluminescence instrument, which is not subject to interference by VOC compounds. The comparisons were carried out in the summers of 1999 and 2000 at urban/industrial sites in Nashville and Houston, and in 2004 aboard a ship in the Gulf of Maine. In the two urban areas, we also compared the O 3 measurements from these two methods with O 3 measurements made by a long-path differential optical absorption spectrometer (DOAS). Our tests indicate that, with wellmaintained monitors, there are no significant interferences even in areas with significant ambient concentrations of potentially interfering VOCs.

Characterization and mitigation of water vapor effects in the measurement of ozone by chemiluminescence with nitric oxide

“…The most widely used instrumental technique for the measurement of tropospheric ozone is by UV absorption (Williams et al, 2006). Ozone UV absorption monitors operate on the principle of ozone absorbing UV light at wavelengths of around 254 nm.…”

A fast and precise chemiluminescence ozone detector for eddy flux and airborne application

“…Gas-phase CI instruments are more complex and are based on the reaction of ozone with either ethene or nitrogen oxide (Ridley et al, 1992;Hegglin et al, 2006;Williams et al, 2006;Bariteau et al, 2010).…”

A Re-Examination of Ambient Air Ozone Monitor Interferences

“…Leston et al 5 reported substantial differences between collocated UV and chemiluminescence measurements during peak O 3 periods in a polluted urban setting. On the other hand, Williams et al 18 found good agreement among UV, chemiluminescence (O 3 -NO), and differential optical absorption spectroscopy (DOAS) O 3 measurements at an urban site and a suburban/industrial location. They also compared the UV and chemiluminescence methods during sampling aboard ship in polluted and clean air.…”

“…Several studies 5,[17][18][19] have compared O 3 measurements made in ambient air by different instruments. Leston et al 5 reported substantial differences between collocated UV and chemiluminescence measurements during peak O 3 periods in a polluted urban setting.…”