Overview

This standard describes the operation of active DOAS measuring systems with continuous radiation source, their calibration procedures and applications in determining gaseous constituents (that is, NO₂, SO₂, O₃, BTX, Hg) in ambient air or in diffuse emissions. The Differential Optical Absorption Spectroscopy (DOAS) is a versatile remote sensing technique for atmospheric trace gases. In this measuring process, the absorption of radiation in the ultraviolet, visible or infrared spectral range by gaseous constituents is measured along an open monitoring path between a radiation source and a spectrometer, and the integral concentration over the monitoring path is determined. DOAS systems support direct multi-constituent measurements. They provide alternative measuring techniques in that they can handle a large number of measuring tasks which cannot be adequately addressed by in situ techniques based on point measurements. Examples of such tasks include the monitoring of diffuse emissions from area sources such as urban settlements, traffic routes, sewage treatment plants and industrially or agriculturally used surface areas, the minimisation of production losses through a detection of leaks in equipment zones or pipeline systems as well as ambient air monitoring in any of the above-mentioned applications. With an appropriate measuring set-up, the local air pollution can usually be assessed very quickly. This also includes measurements in areas which are difficult or impossible to access, or where the direct presence of personnel or equipment is hazardous.

Document: references other documents

Responsible national committee

NA 134-04-02-16 UA - Remote sensing methods  

Responsible european committee

CEN/TC 264 - Air quality