Assessment of Road Traffic Impacts to Change
Air Quality Consultants is responding to the recent Appeal Decision that ruled against the proposed expansion of a Sainsbury’s store in Sheffield on the grounds of air quality, by adding a sensitivity test to all its new reports that deal with road traffic impacts. This will strengthen its’ reports and ensure that they are not open to challenge by local authorities.
The Sheffield appeal decision (for more details see previous news item –click here) highlighted what has been known for some time, namely that emissions of nitrogen oxides from motor vehicles have not been reducing as expected. Air Quality Consultants was involved in drafting guidance to local authorities on behalf of Defra and the devolved administrations on how to respond to the new evidence. This was issued at the end of 2010, but only went as far as saying that local authorities should take into account the evidence that concentrations were not declining as expected, without saying how. Air Quality Consultants responded at the time by adding a section on uncertainty to its reports..
The Inspector, in his report on the Sainsbury’s appeal, criticised the air quality assessment prepared for the development for not including a sensitivity test to show the effects of concentrations not declining as ‘officially’ expected. The ‘official’ expectation is available as a set of emission factors for motor vehicles that provides the basis for modelling air quality impacts of road traffic.
Air Quality Consultants will now be including a sensitivity test in all reports that involve the modelling of future traffic impacts. Reports will now include two sets of findings: 1) future concentrations assuming the ‘official’ reductions in emissions and 2) future concentrations with no reductions in motor vehicle emissions. Both sets of results will be taken into account in determining the overall air quality impact of the scheme.
Air Quality Consultants is increasingly being asked to assess odours. In recent years this has included odours from sewage treatment plant, farmyard cattle slurry and fast-food establishments, as well as hydrogen sulphide odours affecting an office environment. The latest guidance from the Environment Agency, in its H4 document, places increasing emphasis on using sniff tests to assess existing odour sources. One approach involves walking towards a source from a downwind direction and stopping every 10-20 m to sniff the air to detect and describe any odours. Individuals, however, have different sensitivities to odour. The guidance is based around the experience of a ‘typical’ individual.
In order to establish the sensitivity of its consultants, Air Quality Consultants sent six members of staff to have their odour acuity tested. The tests were carried out at the laboratory of OdourNet, where the individuals were asked to sniff the air coming from two ports on the bench in front of them and decide which one had a detectable odour (assessment of olfactory acuity in accordance with BSEN 13725). The concentration of the odour was steadily increased until it could be clearly detected by all six individuals. Four of the six individuals passed this test, and this will be taken into account when staff are assigned to jobs that involve odour assessment. This will help ensure the robustness of the odour assessment reports prepared by Air Quality Consultants.