14. starptautiskā konference 2012 - Latvijas Jūras akadēmija

Proceedings of 14th International conference „Maritime Transport and Infrastructure - 2012”3. Experimental setupDOAS station in Riga's Harbour area is measuring 6 different gases in air every 5-6 minutes,and the values of 10 minutes are stored in central database [6] connecting equipment’s computer everyhour through modem and regular phone. These gases are: sulphur dioxide (SO 2 ), nitrogen dioxide(NO 2 ), ozone (O 3 ), benzene (C 6 H 6 ), toluene (C 6 H 5 CH 3 ) and formaldehyde (HCHO). Measurementequipment is situated along Tvaika Street intermediate the residential area with five-floor houseswhere hundreds of people are living and oil transfer enterprise "Man-Tess Ltd." and "Latvijas RietumuTerminals Ltd." (Figure 1).Fig. 1. Scheme for situation of light beam of DOAS air pollution monitoring station at Riga Harbour(wind blowing from southwest, west and northwest is driving the pollution to light beam).The distance between oil storage tanks, railway platform and first 5-floor apartment house isonly 150 m, and in all cases when the wind blows from the west-north (210-350 degrees) and thecompany transfers oil products from railway tanks to storage or directly in tankers, fumes can reachpeople. We assume that these emissions enter into the light beam and are registered in the airmonitoring station. OPSIS AB (Sweden) equipment AR-500-088 with light emitter ER/RE 150 (largerdiameter) is used. Light source (150 W Xe lamp Type B) is situated on the roof of neighbor enterprise"BMGS Ltd" and light beam is focused on the receiver standing on the roof of container withmeasuring equipment beside J/S company “Aldaris” (Figure 1). Total length of light path is 630 m andthe height from ground is 12 m (emitter) and 4 m (receiver). The light from receiver is enteringanalyzer through optical cable (10 m). Analyzer is upgraded for benzene measurements in 2006, and is70