AIR pollution levels on the M4 at Newport have fallen by almost 40 per cent since the introduction of the 50mph limit, although the average speed cameras are yet to be switched on.

The Welsh Government introduced 50mph speed limits at five clean air zones from June 2018 to address the levels of nitrogen dioxide in the air – including on the M4 between junctions 25 and 26 at Newport.

And in March 2021, the 50mph limit was extended to cover between junctions 24 and 28, as part of the Welsh Government’s approach to tackling congestion in the area, as recommended by Lord Burns’ report.

The five clean air zones were all initially found to have an annual mean concentration of nitrogen dioxide (μg/m3) higher than the limit set out by the Air Quality Standards (Wales) Regulations 2010 and the EU’s Ambient Air Quality Directive – which is 40μg/m3.

However, according to the figures for the 2021, each of the five zones has seen a fall in nitrogen dioxide levels of at least 31 per cent since 2018.

Air pollution levels on the M4 at Newport dropped from 63.5μg/m3 in 2018 – the highest out of the five clean air zones – to 39.2μg/m3 in 2021 – a 38 per cent fall.

The A483 at Wrexham has seen the largest decrease, from 50.2μg/m3 to 25.5μg/m3 (a 49 per cent reduction), while the M4 at Port Talbot saw the smallest decrease – 31 per cent (from 48.4μg/m3 in 2018 to 33.6μg/m3 in 2021).

For four of the clean air zones – with the exception of the A483 at Wrexham – the annual mean for 2021 was higher than in 2020, however much of this can be put down to a lower number of vehicles on the roads due to the coronavirus lockdowns.

It is worth noting, however, that Wales was under lockdown in the first quarter of 2021 - although not quite to the same extent as in 2020.

Last year, the Welsh Government denied it was misleading that Lee Waters, deputy minister for climate change, omitted mentioning the impact of the lockdowns when he said: “It’s clear that the speed restrictions we’ve introduced on our most polluted roads are working - the results speak for themselves.”

The latest figures were published in the Welsh Government's ‘Tackling roadside nitrogen dioxide concentrations in Wales’ plan in September 2022.

Following the publication, a Welsh Government spokesperson said: “Work on the updated Air Quality Plan is ongoing.

“The data that we’ve collected throughout the process demonstrates the positive impact the reduced speed limits have had on air quality across all locations.

“We continue to work closely with the Police and GoSafe to support enforcement at M4 Newport.”

In the plan, it states: “M4 Newport average speed cameras are operational and enforcement will commence shortly.”

Initially, the Welsh Government had said drivers would start receiving speeding fines in the area “in the summer” last year, however this was later revised to October 4, 2021.

However, South Wales Police – which works with GoSafe to administer motoring offences throughout mid- and south Wales – said there had been no substantial update on the progress of bringing the cameras live.

In April, a GoSafe spokesperson said: “Due to the advent of digital technology and the demands upon IT departments to install several camera types, we have reached a point where significant development and investment in systems is required before we can make these schemes live and absorb the extra demand which will arise as part of these schemes.”

And in July, the Argus was told that progress has been made in terms of recruitment, but this is yet to lead to any progress in getting the cameras online.