Long-Path Spectrophotometric Instrumentation for in-situ Monitoring of Gaseous Pollutants in the Urban Atmosphere.

摘要

A long-path spectrophotometric instrument is described for the quantitative measurement of ozone and other infrared absorbing gases (such as sulfur dioxide) in unconfined ambient air. A continuous variable filter wheel is used for wavelength selection from 7to 14microns. The instrument can be used with an active source at a range from 0.4to over 1.6km or it can be used to examine passively the radiant emittance from natural sources. A minicomputer is programmed to control the instrument and analyze the data in real time. The output of spectra or pollutant concentration is on a cathode ray tube, a teletypewriter,and/or punched paper tape. The instrument is sensitive to ozone concentrations ranging from 20microgram/cu. m. (0.01ppm) to 2000microgram/cu. m. (1ppm),with a measured noise of less than 4microgram/cu. m. and a time constant of about two minutes. (Author)