The study area sees the presence of productive activities at risk of a major accident near a village, with emissions into the air diffusive character environment not regulated gaseous pollutants. It was therefore necessary to install on site a continuous analyzer for the measurement of hydrofluoric acid and Hydrochloric Acid. The new measuring station is joined in 2015 by the Regional Network for Detection of Air Quality (RRQA) managed by ARPA Piemonte. Its location has been identified in the area of maximum fallout of the pollutants identified based on the results of modeling studies.
BRIEF DESCRIPTION OF THE OPERATION OF THE ANALYZER
The measuring principle of the tool is the laser absorption spectrophotometry (OA-ICOS). Heart of the instrument is equipped with a cavity with extremely high reflectivity mirrors in which the microwave laser source emits a signal for the species specific absorption of gaseous pollutants of interest. The variation of the laser beam intensity is correlated and proportional to the concentration of HCl and HF present in the measurement cavity (read Beer-Lambert). The optical path traversed by the radiation reaches the 25 Km thanks to the presence of two mirrors (cavity mirrors) with high reflectivity (> 0.99) in the measuring cell: for this reason the instrument is able to achieve high sensitivity and accuracy.
The analysis of the absorption spectra shows the presence of abnormal data and allows to check the presence of interferents
