Simultaneous measurements of atmospheric pollutants and visibility with a long-path DOAS system in urban areas

Abstract

In this paper, the applicability of a Long-Path Differential Optical Absorption Spectroscopy (LP-DOAS) system was checked for the feasibility of the simultaneous measurement of trace gases (such as O-3, NO2, SO2, and HCHO) and atmospheric visibility (light extinction by aerosols) in Asian urban areas. Field studies show that an LP-DOAS system can simultaneously measure the key pollutants (such as O-3, NO2, SO2, and HCHO) at detection limits in the ppb/sub-ppb range as well as the Mie extinction coefficient with an uncertainty of ∼ 0.1 km(-1) at time resolution of a few minutes. It is thus concluded that the use of LP-DOAS system is feasible for simultaneous measurement of gaseous pollutants as well as an atmospheric extinction coefficient which is tightly bound to fine particulate concentration.