Air Quality Investigation of the Planned M0 Motorway Linking the No. 10 and No. 11 Main Roads |
hétfő, 02 június 2008 | |
Dr. Tamás Lajos, Dr. István Goricsán , Márton Balczó Client: National Infrastructural Development Corporation (2007) Under the authority of National Infrastructural Development Corporation the effects of a 9-km-long section of the planned M0 motorway were investigated in wind tunnel and with numerical simulation. The terrain, the settlements and forests were modelled on both sides of the road in an approximately 1.5 km wide interval, altogether in a 28.5 km2 area (Fig. 1.). The scale was 1:1000 so a 28.5 m2-size model (Fig. 2.) was built for the wind tunnel investigations. In 3 junctions 262 sets of concentration measurements were performed with 5-5 dominant wind directions (this means that they cover 80 % of the annual frequency), each set consisted of 10 to 22 sampling points to measure trace gas concentration. Pollutant dispersion was also modelled with MISKAM software, which is widely used for this purpose. The results of the numerical simulation and the wind tunnel measurements were compared, and it was decided that the simulation is suitable to establish environmental protection related and technical decisions. Following the method used in Germany, Austria and Switzerland (HBEFA) and the data of KSH (Hungarian Central Statistical Office), the composition of vehicles and their exhaust were determined for the years 2007 and 2018. According to the numerical simulation and wind tunnel investigations the following statements can be given about the air pollution: From the three investigated pollutants, the maximal CO concentrations do not reach the 20% of the limit. Similarly to the CO, particulate matter is of minor importance. In the cases investigated the strictest limits are the ones of NOx pollutant. The less favourable pollution conditions, affecting the most people are near the no. 11 main road, and affecting less people, at the road no. 10. In case of the surface sections of the new road similar or smaller pollution is expected, but in that case settlements are situated farther from the road. Investigating the possibly most unfavourable conditions (highest, rush hour emissions, lowest wind velocity) in the case of NOx exceeding the hourly limit and affecting some parts of the neighbouring settlements were only experienced in case of concentrated pollution emission from the tunnel exits. In a certain settlement part the frequency of coincidence of low wind velocity and unfavourable wind direction in a year is low, maximum 1 to 3 days. Exceeding the limit can be avoided with a reduction of tunnel length, developing adequate ventilation system, and if necessary, with the exhaust of a certain amount of tunnel air at a point higher from the ground instead of the tunnel exits (Fig. 4.).
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