New full-time 50mph speed limits will be imposed within two months on parts of the M4 in South Wales.
The restrictions between Briton Ferry and Port Talbot and around the Brynglas Tunnels at Newport will be joined by similar limits on the A470 near Pontypridd, the A483 at Wrexham and A494 at Deeside.
Councils will also get funds to introduce clean air zones charging or banning some vehicles from built up areas. Cardiff has already said it wants to restrict access and charge commuters.
They are being introduced not for safety reasons but as part of wide ranging plans by Welsh Government to allow councils to clean up vehicle emissions and meet tough new standards set by Europe and forced through by environmentalists after court action.
The scheme will be outlined tomorrow at a conference in Cardiff for members of the Chartered Institute of Environmental Health.
Welsh Government will create a £20M Air Quality Fund to pay for these changes. Although the money has been allocated and temporary speed limits announced, Welsh Government said there will be a period of public consultation to reduce nitrogen dioxide levels. Advisors have told Welsh Government officials and ministers that the speed limits will cut emissions by up to 18%.
A new Air Quality in Wales website will also be launched, enabling people to check live air quality information for their area. The website will provide local data on current and forecasted air pollution levels, as well as historical data and include educational materials, games and tools for schools and improved health advice.
Minister for Environment Hannah Blythyn will address the conference and said today, “I am delighted to announce a package of measures to improve air quality in Wales, including a £20 million fund to help local authorities put arrangements in place to reduce air pollution in their areas.
“We will encourage local authorities to introduce Clean Air Zones, where evidence suggests they are needed to reduce harmful emissions, as well as launching a new website which allows people to check the air quality in their area.
“Delivering clean air in Wales is one of my key priorities. I am committed to taking action to reduce air pollution in Wales to support a healthier future for our communities and protect our natural environment.
“I am confident the measures I am announcing today will help support the changes we need to make in Wales to deliver cleaner air.”