DIFFERENTIAL ABSORPTION MEASUREMENTS IN LABORATORY ON AIR SAMPLES CONTAINING NO_2 AS POLLUTANT SUBSTANCE

摘要

Laboratory measurements using differential absorption method on air samples containing NO_2 were performed. This type of measurements on standard samples are required for testing and calibration of L1DAR equipment used in remote sensing of atmospheric pollutants. To monitor NO_2, a nitrogen laser pumped tunable dye laser was used, the laser pulse having the following characteristics: energy per pulse 20 μJ, repetition rate 5 pps, pulse time width lns. The working wavelengths were λ_(on) = 435.1 nm and λ_(off) = 432.6 nm, obtained from the dye POPOP in DMSO at 10~(-2) M and the full spectral bandwidth of the laser radiation was 0.8 nm. The air samples contained NO_2 at the concentration in the range 0.4 x 10~(24) m~(-3)-0.75 X 10~(24) m~(-3). NO_2 was prepared in laboratory and analysed by mass spectrometry and spectrophotometry.