Differential absorption lidar (DIAL) applied to the mapping of horizontal air pollution distribution: examples from measurement campaigns in the Czech Republic

摘要

The application of differential absorption lidar (DIAL) in air pollution measurements has become more common over the last two decades. Nevertheless, DIAL studies of the horizontal distribution of air pollution and concentration measurements of organic compounds are still quite rare. This paper presents results of two distinct measurement campaigns performed in the Czech Republic, where a mobile DIAL system was employed in order to collect information about the horizontal distribution of pollutant concentration. In the first campaign the concentration of toluol over a chemical plant in Usti nad Labem (city in North Bohemia) was investigated. The results of the DIAL measurements were compared with data collected simultaneously by a stationary differential absorption spec-troscopy device (DOAS). Time developments of toluol concentrations measured by DIAL and DOAS were in good agreement. Moreover, the results of DIAL measurements traced a narrow area suspect of toluol leakage. In the second campaign the horizontal distribution of ozone concentration over a Prague suburban area was studied. DIAL measurements detected a mild but statistically significant increase in ozone concentration just above a highway gas station that was located within the area studied. Volatile organic compounds (VOC) are known to act as a catalyst in the process of ozone formation. Thus the observed increase in ozone concentration can be due to a higher concentration of VOC in the area near the gas station.