In case you hadn’t noticed, December saw a  major battle going on between red and blue – And we’re not just talking about the battle between Liverpool, Manchester City and Leicester City.

Brexit has dominated the political landscape and will continue to dominate discussions, but another major topic of debate is the environment and what we should do to protect it.

Football horse racing fans who watch their favourite team week after week, home and away, may not know how clean the air is at the Premier League stadiums they visit regularly?

We have carried out a study to see which team is top of the table for having the best air quality at their grounds and which grounds have the worst air quality that could lead to health issues.

Arsenal’s Emirates Stadium has one of the highest pollution levels in the UK with a nitrogen dioxide rating of 3.

Norwich City may were green shirts, but their Carrow Road ground is one of three stadiums in the Premier League that is ranked the worst for pullution levels in the top flight.

In a project to highlight concentration of nitrogen dioxide (NO2) in the UK, Carrow Road has a rating of three out of six.

The study concentrates on NO2 pollution which scientists believe are a good indication that other pollutants may also be present. The Canaries’ rating of three means it is likely that nitrogen dioxide levels will exceed the annual legal limit.

The law states that hourly levels of toxic NO2 must not exceed 200 micrograms per cubic metre more than 18 times in a whole year.

A rating of three means that at peak traffic times, the quality of air will get worse especially in stagnant weather conditions.

Spending long periods of time in these conditions could cause minor long-term health concerns. The rating at the ground is higher than the average for the city of Norwich which has a level of one.

The other two clubs whose stadiums have a rating of three are both in the capital.

Arsenal’s Emirates Stadium in north London, which was opened in time for the start of the 2006/07 season, and Chelsea’s Stamford Bridge in the west of the capital join Norwich at the wrong end of the table.

The distance between Arsenal and their neighbours Tottenham is only four miles, but the new Tottenham Hotspur Stadium opened in April this year at a cost of over £1b has a rating of two.

The study into pollution levels says that this rating means there is a low-to-moderate chance of nitrogen dioxide levels exceeding the annual legal limit.

The air quality is moderately clean and should not cause health issues except in exceptional weather conditions.

The other three clubs based in the capital have a rating of two while Molineux, home of Wolves in the Midlands also has a rating of two out of six.

The King Power Stadium, home stadium of Leicester city football club has one of the much better nitrogen dioxide levels with a rating of 1.

Aston Villa, who are 21 miles away along the M6 and M54, is one of 12 clubs whose grounds have a rating of one as does Leicester’s King Power Stadium.

This rating means there is a low chance of average nitrogen dioxide levels exceeding the annual legal limits.

The air in this area is generally clean although there may still be some high concentrations of NO2 located close to major roads.

The three Premier League stadiums on the south coast – Brighton, Bournemouth and Southampton – also have a ranking of one.

And in the north of England, both stadiums in Manchester – Man United’s Old Trafford and Man City’s Etihad and the two in Liverpool – Anfield and Everton’s Goodison Park have a rating of one.

Elsewhere in the north of England, Sheffield United’s Bramall Lane, Burnley’s Turf Moor and Newcastle’s St James’ Park are all rated one.

There is still work to be done to improve pollution up and down the country and whoever forms the next Government, their promises to make Britain a cleaner place to live and to watch football will have to be delivered.

Pollution league table/nitrogen dioxide (NO2) levels

3 – Arsenal
3 – Chelsea
3 – Norwich
2 – Crystal Palace
2 – Tottenham
2 – Watford
2 – West Ham
2 – Wolves
1 – Aston Villa
1 – Bournemouth
1 – Brighton
1 – Burnley
1 – Everton
1 – Leicester
1 – Liverpool
1 – Man City
1 – Man United
1 – Newcastle
1 – Sheffield United
1 – Southampton