Air pollution is considered a large threat to human health. Freight transport vehicles are responsible for a large share of air pollution. The impact of pollutants is heavily depending on the number of people present in the proximity of the emission source. This impact is generally calculated using the impact-pathway-approach. Yet, the geo-temporal link between the emission source and the number of people in proximity of that source is currently considered to be static.
Dynamic methodology
Research by Vrije Universiteit Brussel presents the combination of dynamic receptor densities and dynamic emission sources by quantifying the impact of air pollution (particulate matter and mono-nitrogen oxides) generated by urban freight transport in the Brussels Metropolitan Region. The results of this approach were compared to the current practice in the literature.
Very large differences, up to factor 45, were found on the local level. The proposed dynamic methodology should consequently be used for micro-scale analyses on transport-related air pollution. However, the overall difference for the entire Brussels Metropolitan Region is neglectable (0,5%).
Policymakers
The research highlights the necessity to make use of a dynamic approach when conducting local-level analyses, given the more accurate (but still conservative) impact of freight transport-generated air pollution (external costs). Indeed, the latter has been found to be drastically higher using the dynamic approach than previously assumed using the conventional static methodology.
For policymakers, it is advisable to facilitate a three-fold shift of freight transport operations. First a geographical shift, where flows are shifted or pushed towards roads in regions with relatively low receptor densities. Second, a shift in time towards the off-hours to reduce both the impact of congestion and the number of receptors in the near surroundings of the freight vehicle. Lastly, authorities could use this information to promote a modal shift towards rail and barge as to potentially reduce congestion and air pollution levels.