Evaluation of Monitoring Methods for Nitrogen Oxides

This study was carried out to compare data of various dynamic monitoring methods for nitrogen oxides to the calculated data from a dynamic gas generator in the laboratory and to the data from a chemiluminescence analyser in the field. Chemiluminescence analysis is considered to be the most accurate method in the literature and our study showed it to be so. Detector tubes turned out to have the next best overall performance. The liquid sorbent method for nitrogen dioxide (NO2 gave also acceptable results both in the laboratory and in the field experiments. The collection efficiency of the liquid sorbent method was 78% for NO2 in the laboratory. Good accuracy was also obtained with the electrochemical analyser in the laboratory, although this method was not reliable in field conditions. The collection efficiency of the solid sorbent tube method was poorer than reported in the literature, being only 69% in the laboratory tests for NO2 and 85% for nitric oxide (NO). The results of the solid sorbent tube method were also low in the field tests being only 54% for NO compared to chemiluminescent data. The solid sorbent tube method gave acceptable results for NO2 (90%) in the field tests compared to chemiluminescence analyser.