To ask the Secretary of State for Transport with reference to his Department's document, Road Vehicle Emission Factors 2009, what the (a) laden and (b) unladen full emissions profile per mile is of (i) diesel and (ii) petrol (A) 38 tonne heavy goods vehicles (HGV), (B) 44 tonne HGVs, (C) transit type vans and (D) family saloons.

The Road Vehicle Emissions Factors 2009 research project provided recommendations on improving methodologies and some of the input data required to model national air pollutant emissions from road transport. To estimate UK average emissions profiles for different vehicle types requires these recommendations to be combined with UK fleet composition and total traffic activity data.

The following figures for oxides of nitrogen (NOx), particulate matter (PM10), carbon monoxide (CO), non-methane volatile organic compounds (NMVOC) and methane (CH4) emissions have been generated by the National Atmospheric Emissions Inventory, which AEA Technology produce under contract to DEFRA. This combines the 2009 emissions factors with national fleet and traffic data to produce estimates of total UK emissions. The CO2 emissions figures are derived from DEFRA's greenhouse gas reporting guidelines, these use the 2009 emissions factors (along with fleet and traffic data) plus improved data on HGV CO2 emissions from DFT freight surveys.

The 2009 emissions factors reflect average vehicle loading and do not provide corrections to adjust for different vehicle loading states. However, the greenhouse gas reporting guidelines do provide data for different loading states for HGVs (figures for other vehicle types reflect emissions at average loading).

It should be noted that some of the vehicle categories are not necessarily directly compatible, e.g. petrol vans appear to have lower CO2 emissions than diesel vans suggesting that the petrol vans modelled are on average smaller and lighter than the average diesel vans modelled.