Impacts of using reformulated and oxygenated fuel blends on the regional air quality of the upper Rhine valley

[摘要] The effects of using three alternative gasoline fuel blends on regional airquality of the upper Rhine valley have been investigated. The first of thetested fuels is oxygenated by addition of ethyl-tertio-butyl ether (ETBE),the second is based on a reformulation of its composition and the third on isboth oxygenated and reformulated. The upper Rhine valley is a very sensitiveregion for pollution episodes and several meteorological and air qualitystudies have already been performed. High temporal and spatial emissioninventories are available allowing relevant and realistic modifications ofthe emission inventories. The calculation period, i.e., 11 May 1998,corresponds to a regional photochemical ozone pollution episode during whichozone concentrations exceeded several times the information threshold of theozone directive of the European Union (180 μg m^-3 as 1 hourlyaverage). New emission inventories are set up using specific emission factorsrelated to the alternative fuels by varying the fraction of gasolinepassenger cars (from 50% to 100%) using the three fuel blends. Then airquality modeling simulations are performed using these emission inventoriesover the upper Rhine valley. The impact of alternative fuels on regional airquality is evaluated by comparing these simulations with the one using areference emission inventory, e.g., where no modifications of the fuelcomposition are included. The results are analyzed by focusing on peak levelsand daily averaged concentrations. The use of the alternative fuels leads togeneral reductions of ozone and volatile organic compounds (VOC) andincreases of NO_x levels. We found different behaviors related to thetype of the area of concern i.e. rural or urban. The impacts on ozone areenhanced in urban areas where 15% reduction of the ozone peak and dailyaveraged concentrations can be reached. This behavior is similar for theNO_x for which, in addition, an increase of the levels can be noted inurban plumes over rural areas. The most important decreases of the totalVOC levels are mainly located over rural areas (more than 5%reduction of the levels except in urban plumes). By comparing these resultswith those from a local study related to the air quality of Strasbourg, weestimate that the regional contribution to the urban air quality ofStrasbourg allows an enhancement of the results by using alternative fuelblends at the regional scale.

[学科分类] 大气科学