Roads
Whilst legislation has been effective at reducing emissions of PM from the exhausts
of internal combustion engines, the non-exhaust emissions (NEE) proportion of road
traffic has increased13. Data from the UK National Atmospheric Emissions Inventory
indicate that particles from brake wear, tyre wear and road surface wear currently
constitute 60% and 73% (by mass), respectively, of primary PM2.5 and PM10
emissions from road transport, and will become more dominant in the future. That is
approximately 7.4% and 8.5% of all UK primary PM2.5 and PM10 emissions,
collectively exceeding those from the exhaust of the UK vehicle fleet.
The City of Edinburgh Council
The City of Edinburgh Council – 2025 Draft PM10 Air Quality Action Plan 17
Resuspended road dust is not estimated in the national inventory; however, it
constitutes a significant road PM source14. Dust can accumulate on road surfaces
from natural mineralogy e.g. soils or industrial sources e.g. sand, cement processing,
and it is often heavily contaminated with brake and tyre wear. Some of this material is
in the PM10 size range when depositing to the road surface and the action of tyres on
surface dusts may also cause some grinding leading to the creation of smaller
particles. Such particles are easily suspended from the road surface, both by shear
forces at the tyre-road interface and by atmospheric turbulence in the wake of the
vehicle. Elevated wind speeds also contribute to the resuspension of surface dust.
The most effective mitigation strategies for NEE are to reduce the overall volume of
traffic, lower the speed where traffic is free-flowing (e.g. trunk roads and motorways),
and promote driving behaviour that reduces braking and higher-speed cornering.
Resuspension of particles from the road surface can be lowered by reducing the
material that is tracked onto public road surfaces by vehicle movements in and out of
the docks, construction sites, waste-management sites and other similar sites; and
potentially by road sweeping, street washing and application of dust suppressants to
street surfaces, although the impacts on airborne PM from trials of these latter
approaches have so far proven inconsistent and any benefits have been short-lived.
#Particulates #Pollution
Fascinating from #SalamanderStreet #AQMA report
-> www.edinburgh.gov.uk/downloads/fi...
🙋 total UK brake, tyre, road-surface wear particles now exceed total from exhausts
@edi.bike @blackfordsaferoutes.co.uk @asthmalungscot.bsky.social @foescot.bsky.social @transform.scot