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 remote vehicle sensing devices has been developed in the United States to identify such vehicles. An important factor that influences vehicle emissions is the operating mode of the vehicle. The influence of this factor can be reduced through careful choice of monitoring site. Although motorway off-ramps offer convenient sites for remote sensing devices much of the urban fleet rarely leaves the urban confines, so would not 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 roads in the London Borough of Southwark. The siting of remote sensing devices is discussed. Of the vehicles at these sites, a number of vehicles repeatedly pass the test sites allowing several measurements to be made for the same vehicle. These results can then be used to assess the 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 sensing of emissions is discussed and preliminary results are presented.