Heatwave saw air pollution levels soar in Maidenhead & Windsor

Last week’s heatwave, where the highest ever temperatures were recorded in Britain, produced dangerously high levels of air pollution in London and the South East, including in Windsor and Maidenhead.

Data from monitoring sites at Frascati Way and Aldebury Road in Maidenhead and Clarence Road in Windsor reveals that on Tuesday 19 July, Royal Borough air pollution monitoring sites recorded levels of nitrogen dioxide which exceed World Health Organisation (WHO) safe limits.  Levels of PM10 particulates recorded in Maidenhead on the hottest day of the year were within a whisker of the WHO safe limit.

Ozone is normally formed when other pollutants, including nitrogen dioxide, react in sunlight.  Ozone levels increase in polluted air on sunny days, leading to summertime ‘smog’.  On 18 July DEFRA issued a National ozone air pollution alert and levels to the East of Windsor exceeded WHO limits on seven consecutive days during the heatwave.

Thomas Wigley, Windsor resident and member of the Maidenhead Great Park campaign group, explains:

“Our government and the Royal Borough recognise air pollution as a major health risk, ranking alongside cancer, heart disease and obesity.  It shortens lives and damages quality of life.

“The Royal Borough of Windsor & Maidenhead’s air pollution monitoring is very limited, but where health damaging pollutants are measured at Frascati Way in Maidenhead and at Clarence Road in Windsor, the heatwave pushed Nitrogen Dioxide levels dangerously high.

“Ozone is a gas which is damaging to human health and can trigger inflammation of the respiratory tract, eyes, nose and throat, as well as asthma attacks.  Ozone can also have adverse effects on the environment through oxidative damage to vegetation, including crops. 

“Our council doesn’t currently measure Ozone, but at nearby Hillingdon and Harlington, ozone levels consistently exceeded the WHO limit during the heatwave.  Pollution drifts, and Maidenhead and Windsor are both under flight paths and close to major motorways, so it’s likely they were also affected by it.

“One of our Council’s declared Corporate Plan objectives is to achieve National Air Quality Objectives in all five Air Quality Management Areas in the Borough, but there are ten different pollutants and the Borough currently only measures two of them. 

“It is impossible for RBWM to achieve National Air Quality Objectives by 2025 because it doesn’t measure 90 per cent of pollutants which have National Air Quality Objectives.

“One of a number of key aims in our Council’s Environment & Climate Strategy is to have cleaner air and to green our urban environment. The strategy recognises the need to reduce air pollution to reduce inequality for those who are disproportionately impacted by pollution.

“Yet our council’s Borough Local Plan commits to building 2,000 new homes on the publicly owned woodlands and greenspace of Maidenhead golf course.  Thousands of mature trees are going to be cut down.  Trees and vegetation help to improve air quality, so building on the golf course will remove this vital green lung for our community. This loss, combined with increased road traffic created by the cars of thousands more residents, as well as 10 years of major construction traffic, will make air pollution in Maidenhead much worse than it is now.

“It’s vital that our council properly monitors and takes effective action to tackle air pollution.  In March, we started a petition asking RBWM to increase and improve its measurements of health damaging air pollutants.  So far we have 851 signatures, but if 1,500 or more people have signed it by 8 September, the petition will be debated at Full Council.

“People can sign the air pollution petition at https://rbwm.moderngov.co.uk/mgEPetitionDisplay.aspx?ID=2163&RPID=8125846&HPID=8125846 or there’s a paper copy at the Filling Good Shop, 22 High Street, Maidenhead.”

Key Findings from Thomas Wigley’s ‘July Heatwave Air Pollution Analysis’, 24 July 2022:

• Nitrogen Dioxide (NO2) concentrations were measured at Hillingdon, Harlington, Frascati Way (Maidenhead), Aldebury Road (Maidenhead) and Clarence Road in Windsor.  Ten values exceeded the WHO AQG.  The peak value of 59 ug/m3, recorded at Hillingdon on 18 July, is more than twice the WHO AQG.  All the monitoring sites, apart from Aldebury Road in Maidenhead, displayed similar NO2 concentration trajectories.
• Ozone concentrations were measured at Hillingdon and Harlington.  48% of all readings exceeded the WHO AQG (20 readings out of 42).  The highest 8-hour mean value of 132 ug/m3 was recorded at Harlington on 19 July.  This value is more than twice the WHO AQG value of 60 ug/m3.  38% of all readings exceeded the WHO AQG by more than 110%.
• PM10 Particulates concentrations were measured at Hillingdon, Harlington and Frascati Way in Maidenhead.  All sites reached peak values on 19 July with the highest value of 17.2 ug/m3 recorded at Hillingdon on 19 July; 98% of the WHO AQG value of 45 ug/m3 as a daily average.
• PM2.5 Particulates concentrations were measured at Hillingdon and Harlington.  All sites reached peak values, which exceeded the WHO AQG, on 19 July with the highest value of 43.9 ug/m3 recorded at Hillingdon on 19 July; 115% of the WHO AQG value of 15 ug/m3 as a daily average.