AIR pollution reached 'potentially unsafe' levels on seven days at a monitoring station in Warrington last year – a two-day increase from 2016.

The Department for Environment, Food and Rural Affairs (Defra) has published air quality data for 89 monitoring stations throughout the UK.

The town's site – which is situated at Sacred Heart Catholic Primary School, near Sankey Way – operates throughout the year.

Stations measure the concentration of different pollutants in the atmosphere that are harmful to humans.

These include particulate matter, small airborne particles of soot and dust which humans can inhale, nitrogen dioxide, which irritates the airways and ozone and can harm plants, as well as the throat, eyes and lungs.

At the borough's site, the main cause of the days with high pollution levels was particulate matter.

But Warrington Borough Council has reaffirmed its 'commitment' to improving air quality.

A spokesman said: "Defra provides air quality health advice using a system known as the Air Quality Index to rate current air pollution on a scale of 1 to 10, banded as low, medium and high.

"Typically, air quality in Warrington is classed as 'low' using the index, but there can be times when the air quality is worse due to weather influences that affect dispersion of pollutants.

"In 2017, there were seven days when the air pollution levels from particulates were classed as 'moderate'.

"The health advice at those levels is that the general population should continue to enjoy outdoor activities.

"However, 'at risk' individuals with existing heart or lung problems, who experience problems, are advised to consider reducing strenuous physical activity, particularly outdoors.

"The information is publicly available and forecasts and warnings can be provided to the public via e-mail and social media.

"The council is committed to improving air quality and the health of all of Warrington's residents.

"An air quality action plan has been developed to implement actions aimed at improving air quality across the borough.

"The action plan includes a measure to improve the air quality section of the council website and, as part of this, air pollution forecasts and health warnings will be considered."

The authority also has smaller roadside analysers on Parker Street and Chester Road, as well as an extensive network of NOx tubes on lampposts throughout Warrington, which are changed monthly and sent away for analysis.