Air quality improvement,especially in urban areas, is one of the major concerns. For this reason. car and equipment manufacturers and refiners have been exploring various avenues to comply with the increasingly severe anti-pollution requirements. Adulteration of fuels stands as a roadblock to this improvement. In this paper, fuel consumption, particulate matter and exhaust emission measurements from a single cylinder. stationary Diesel engine are presented. The engine was fuelled with automotive Diesel fuel, which was adulterated with domestic heating Diesel in proportions up to 100%. The four types of adulterated Diesel fuel investigated increased all types of emissions compared to automotive Diesel fuel. The only positive result was a slight decrease of the volumetric fuel consumption in some loads. (C) 2004 Elsevier Ltd. All rights reserved.