REMOTE-SENSING OF VEHICLE EMISSIONS ON BRITISH URBAN ROADS

Vehicle emissions are a major source of air pollution in urban areas. The impact on urban air quality could be reduced if heavily emitting, poorly maintained vehicles are identified and repaired. The use of rem ote vehicle sensing devices has been developed in the United States to identify such vehicles. An important factor that influences vehicle e missions is the operating mode of the vehicle. The influence of this f actor can be reduced through careful choice of monitoring site. Althou gh motorway off-ramps offer convenient sites for remote sensing device s much of the urban fleet rarely leaves the urban contines, so would n ot be seen by monitors at these sites. This paper discusses the use of a remote sensing device, the FEAT system [1], on two British urban ro ads in the London Borough of Southwark. The siting of remote sensing d evices is discussed. Of the vehicles at these sites, a number of vehic les repeatedly pass the test sites allowing several measurements to be made for the same vehicle. These results can then be used to assess t he performance of the monitor at different sites. The data reported in this paper indicate that 85% of vehicles with two readings have both below 2% CO. Vehicles with at least one high reading have a 27% chance of having both readings high. The effect of acceleration on remote se nsing of emissions is discussed and preliminary results are presented.