Pollution levels still too high
NO2 figures
POLLUTION remains dangerously high on major Welsh roads at levels that cause increased heart and lung problems – as well as harming children’s development.
Figures show that the Welsh Government’s 50mph speed limits have cut the levels of dangerous nitrogen dioxide on major roads but they remain far above the EU and Welsh safe levels.
Nitrogen dioxide, which is produced when fossil fuels are burned, can inflame the airways in our lungs, causing lifelong problems for growing children and exacerbating conditions in adults like asthma.
50mph speed limits have introduced in several areas including: the M4 by junction 41 and 42, in Port Talbot; Junction 25 and 26 in Newport; the A470 between Upper Boat and Pontypridd; A494 at Deeside; and A483 in Wrexham.
On October 4, Welsh Government said pollution had been cut at these five spots in Wales and while more work was needed “initial findings are positive”.
However, the data show that in some areas pollution is still more than 50% above the safe level.
We have looked at the data provided and spoken to experts to analyse the figures published in the latest Welsh Government report.
The annual average concentration level of nitrogen dioxide (NO2) must not exceed 40μg/m3, according to the EU Ambient Air Quality directive, which came into force in 2010.
To check the levels, the Welsh Government WHEN looking at roadside concentrations – where 40 is the legal limit – levels were exceeded at all monitored roads. The first figure is site NO2 concentrations before 50mph speed limits and the second figure is NO2 concentration after 50mph speed limit
M4 Newport A470 Pontypridd M4 Port Talbot
URBAN background concentrations – where 40 is the legal limit
M4 Newport A470 Pontypridd M4 Port Talbot
64.0 60.4 52.2
24.7 18.7 14.1
61.5 53.3 45.0
23.2 18.4 12.8 recorded data for six months, from December 2017 to June 2018, which was before speed limits were changed, and for a year after their introduction between July 2018 and July 2019.
Before the speed limits, roadside concentrations of NO2 in all five areas exceeded the legal limit. A year later, in July 2019, the concentration level had reduced in all five areas but was only within legal limits in one place: Deeside, where the measurement was 39.
Of all five areas, Newport and Pontypridd have the highest concentration levels. The M4 in Newport has the smallest reduction in a year from 64 to 61.5 – still way above the 40μg/m3 level. In Pontypridd the levels reduced from 60.4 to 53.3 in a year.
Victoria Seller, air quality research officer at Swansea University, said: “It is really difficult to say whether further measures will be needed or whether the impact [of the speed limit reduction] will be enough to bring compliance.”