Aspects of year-long differential optical absorption spectroscopy and ground station measurements in an urban street canyon near industrial pollution sources

The annual performance of a differential optical absorption spectroscopy (DOAS) system in combination with a ground monitoring station was assessed in an urban street canyon of a medium-sized city, Greece. The urban environment is surrounded by complex terrain and located in proximity to coal-fired power plants. One-year hourly concentrations of ozone, nitrogen dioxide (NO2), and sulphur dioxide (SO2) that have been measured by DOAS were correlated against data from a conventional ground station. Concentrations of volatile organic compounds (benzene, toluene, and p,m-xylene) have also been presented and their photochemical role was related to their degree of reactivity. Experimental data of photochemical pollutants were significantly correlated against meteorology during a 7-day period. The parallel monitoring at ground and DOAS path levels has contributed in the verification of distant pollutants’ transfer from the industry. The importance of wind speed in the photochemical production of ozone by was also stipulated the distinction of urban and rural conditions.