A number of changes have recently been made to the Local Air Quality Management tools available on the air quality archive website (www.airquality.co.uk). The new tools should be used for new work. If work has already been started using the old set of tools, it is not necessary to go back and repeat the work unless the local authority believes that this would be appropriate. So long as models have been appropriately verified against local measurements, the updates to the tools should not invalidate work already carried out, even though precise results would be different. The changes are as follows:
1) The Emission Factor Toolkit (EFT) has been updated to use the DfTs latest vehicle emission factors (published in 2009). This allows modellers to calculate vehicular emissions in line with the latest predictions. It is possible for users to incorporate the emissions that they calculate using the EFT into most dispersion models (but not screening tools such as DMRB).
2) The NOx to NO2 calculator has been updated. These changes take account of more recent predictions of oxidant levels across the UK and also use revised default values for primary NO2 (fNO2) (as shown within the spreadsheet).
3) The national maps of background air pollutant concentrations have been updated to take account of more recent emissions predictions and updated methods. A short report describing the principal changes between the two sets of maps is included on the website along with the maps.
4) The sector-removal tool for calculating sector-adjusted background nitrogen dioxide concentrations has been updated following changes to the background mapping methodology.
5) The future-year projection factors for roadside monitoring data contained in Box 2.1 of LAQM.TG(09) have been updated.
All of these tools can only be applied to data from the year 2008 onward. An FAQ on modelling conditions prior to 2008 will follow soon.
If local authorities require any help or clarification they should contact the Review and Assessment Helpdesk on 0117 32 83668 or aqm-review@uwe.ac.uk.
