AIR pollution figures in Newport and Chepstow exceed World Health Organization (WHO) guidelines, research shows.

Figures from the WHO shows 44 out of 51 cities and towns in the UK breached guidelines for air quality.

Newport has a rating of 13 micrograms per cubic metre of air, while Chepstow ranked higher with 14, the same as Cardiff and Birmingham.

Exposure to the particles, known as PM2.5s, should not exceed 10 micrograms per cubic metre of air, according to the organisation.

The particles have been linked to heart disease and premature death.

A spokeswoman for Newport City Council said: "Newport, similar to most cities, suffers from poor air quality which is mainly attributed to vehicle emissions.

"The city’s road network has developed over hundreds of years and been adapted to accommodate an ever increasing number of motor vehicles.

"Data from the Department for Transport indicates a 17 per cent increase in road vehicles in Newport over the last 15 years.

"Studies have been undertaken across the City’s AQMAs to investigate what road network modifications could be undertaken to improve the air quality and traffic flows.

"However, in most cases little can be done to the road network, given the current traffic volumes. Ultimately, to improve air quality, the volume of road vehicle traffic needs to be reduced, and the council are in the process of updating their Air Quality Action Plan to recommend such measures."

A spokesman for Monmouthshire County Council said the primary source of pollution in Chepstow is the A48 trunk road.

The spokesman said: "Emission levels along the A48 through Chepstow have reduced in recent years.

"However the council’s environmental health section continues to review and assess pollution levels and the council works with key stakeholders to implement the action plan and reduce vehicle emission levels."