TRUE publication

Assessment of real-world vehicle emissions from four Scottish cities in 2022

Continuing its work with Transport Scotland, the TRUE Initiative deployed remote sensing technology in four Scottish cities in 2022 to measure emissions from on-road vehicles and thereby inform air pollution policies and identify opportunities for further action. Around 660,000 vehicular emissions data were collected in April and September 2022 across Aberdeen, Dundee, Edinburgh, and Glasgow.

Among other findings, this study assesses that strengthening low-emission zone restrictions and implementing age or mileage limits alongside emission standard-based policies could help promote air quality in urban areas in Scotland. Moreover, encouraging the maintenance or replacement of taxis and private hires—which produce consistently higher emissions than other passenger cars—could yield outsized emission benefits relative to these vehicles’ share of the fleet. Applying an emergent approach to identifying high-emitting trucks, this analysis also shows that remote sensing could help to identify potentially faulty vehicles or vehicles fitted with defeat devices, and defines an enforcement threshold to identify high-emitting trucks for interdiction and inspection.