Road congestion and real world emissions were among topics at the annual Dispersion Modellers User Group (DMUG) event
Road congestion and real-world emissions were among issues put under the spotlight by air quality experts at the annual Dispersion Modellers User Group (DMUG) conference in London yesterday (April 19).
Speakers at the event, organised by the Institute of Air Quality Management (IAQM), included Nigel Bellamy, air quality advisor at government agency Highways England and Dr Ben Marner, technical director at Air Quality Consultants Ltd.
Focusing on the newly developed DMRB GIS Toolkit (Design Manual for Roads and Bridges, Geographical Information System) Mr Bellamy said that monitoring emissions is â€œfundamentalâ€ for Highways England and â€œunderpins everything they doâ€.
He noted that congestion is an important aspect in air quality monitoring, despite some of the featured models â€“ notably the Streamlined-PCM (pollution climate mapping) â€“ not featuring traffic congestion as a standard option.
The latest version of DMRB has been used at some of Highways Englandâ€™s 1,500 monitoring sites across the country, Mr Bellamy said.
As part of the presentation â€“ Mr Bellamy demonstrated emissions testing using DMRB over four periods throughout the day including peak times. It was found that in the afternoon, the flow of traffic goes up but importantly the emissions go down â€“ attributed to the decreased use of Heavy Duty Vehicles (HDVs) at peak times.
â€œThere is a strong emphasis on collaborative work between the road traffic team and air quality team” – Nigel Bellamy, Highways England
Highways England frequently monitor key locations with air quality risks, he added: â€œThere is a strong emphasis on collaborative work between the road traffic team and air quality team.â€
Later, Dr Ben Marner turned the focus to real-world emissions, stating that Euro 4 and 5 diesel cars have â€œperformed no-where near as good as in testingâ€ but that â€œthis is to become increasingly irrelevant over the next few yearsâ€.
He explained: â€œIt is the performance of the vehicles that are coming onto the roads in the next few years that are going to hold the key to the future, rather than anything that has happened in the past.â€
Discussing the new traffic emissions calculator, he said that in relation to Euro 5 vehicles, the COPERT (Calculation of Pollutant Emissions from Road Transport) 4 model, used in Defraâ€™s Emissions Factors Toolkit (EFT) is â€œunder-predicting emissions from heavy vehiclesâ€.
Also speaking at the event was Michel Verdenne, senior consultant at Ricardo Energy & Environment, who discussed the Streamlined-PCM tool and the impact of changing the measures applied as part of the tool on nitrogen oxides (NOx) and nitrogen dioxide (NO2) emissions at road receptors in the UK.
Mr Verdenne provided an overview of the toolâ€™s use as a model of emission concentrations in Norwich, but explained that while the tool is currently used by Defra as part of its EU air quality directive, it is not currently available for widespread use.