The Government have commissioned and published various pieces of research into the effects of biofuels on air quality. These include an evaluation of the impacts of vegetable oil fuel on the emissions of two light duty diesel vehicles available at:
http://www.dft.gov.uk/pgr/roads/environment/research/cqvcf/dftbiofuelsevaluationofemiss3823 and an evaluation of the potential impact of bioethanol on emissions of a wide range of air pollutants available at:
The Government have not commissioned any research specifically on the effects of biofuels on asthma, but a recent Department of Health call for research on the health effects of air pollution included a call for studies on the health effects of biofuels, as transport fuels or for domestic heating. In addition, the Department of Health provides programme funding to the social medicine and health services research unit at Imperial college which conducts epidemiological studies on asthma, including on air pollution.