New data shows that air pollution levels across Oxford saw overall improvement during 2022

Data from Oxford City Council’s annual Air Quality Annual Status Report has found that during 2022, overall NO2 levels across the city decreased by 8.3% on average, with a 24% drop when compared to pre-pandemic (2019) levels.

The data follows the publication of Oxford City Council’s latest Air Quality Annual Status Report for 2022, which examines air pollution levels across 127 locations in the city, with 37 new sites added for 2022.

The data covers the period of January 2022 – December 2022, and includes initial findings following the introduction of the East Oxford LTNs (introduced in May 2022), and the Zero Emission Zone pilot in Oxford city centre (introduced in February 2022).

Before the pandemic, air pollution levels in the city were plateauing, however the pandemic (2020) saw a 29% drop in air pollution levels- the lowest recorded levels since data was first monitored in 1996 – this decrease was largely due to a reduction in road traffic during lockdowns.

The following year (2021) saw a 14% increase in air pollution levels compared to 2020, largely due to the easing of coronavirus lockdown measures and increasing traffic across the city. In order to see another major reduction more action is needed to reduce the number of cars on the road and promote electric vehicle use.

Some of the highlights of the latest 2022 Air Quality Annual Status Report are:

• Overall air pollution (NO2) levels have decreased across the city by 8.3% on average.
• Compared to pre-pandemic (2019) levels, 2022 saw a 24% reduction in air pollution.
• The legal annual mean objective of 40µg/m3 was exceeded at six locations within the city. However, only one is located in a place considered of high public exposure (St Clement’s).
• St Clement’s Street/The Plain, which is traditionally Oxford’s most air-polluted road, continued to have the highest air pollution levels, with a 10% increase in 2022– from 39µg/m3 to 43µg/m3. This figure is higher than the UK’s annual legal limit, however, it remains lower than pre-pandemic levels at this site, which recorded 53μgm3 in 2019.
• A further five monitoring locations measured increased NO2 levels above the legal limit (40µg/m3): Three locations are along the ring road, on the Southern Bypass - south of Botley Interchange (which falls outside the City Council’s jurisdiction), and Headington Hill. However, these locations are not in residential areas or areas where the public regularly are exposed.
• Hollow Way Road saw no significant change in NO2 levels during 2022 (a 1μgm3 decrease from 35μgm3 to 34μgm3). This road remains lower than pre-pandemic (2019) levels, which recorded 37μgm3 in 2019. 
• Oxford Road/Between Towns Road saw no significant change in NO2 levels during 2022 (with levels remaining at 30μgm3). This road remains lower than pre-pandemic (2019) levels, which recorded 32μgm3 in 2019.
• Oxford Road/Cowley Police Station saw no significant change in NO2 levels during 2022, (with levels remaining at 29μgm3), and this road remains lower than pre-pandemic (2019) levels, which recorded 31μgm3 in 2019. 
• Within the Zero Emission Zone pilot and on boundary streets – NO2 levels decreased overall.
• All locations monitored within the East Oxford LTNs showed a decrease in NO2 levels.
• While NO2 levels have decreased by 8.3% on average, traffic levels within the city have increased by 8.2%. A likely contributor to this balance is due to the increase in the electric vehicles on our roads – with Oxfordshire having the highest electric vehicle uptake figures for new registered vehicles in the UK.
• Twelve locations within the city were above the Council’s own local annual mean target (30µg/m3) for NO2. These locations are: Cutteslowe Roundabout, St Aldates, High Street (2x), Long Wall Street, St Clements (x2), Hollow Way Road, Worcester Street, Park End Street, Oxford Road/Newman’s Road, and Oliver Road.
• Particulate Matter (PM10 and PM2.5) saw no significant increase or reduction compared to 2021 levels. 

The full air pollution report is available to view here

East Oxford Low Traffic Neighbourhoods (LTNs)

The monitoring results from 2022 assessed the air quality levels within the East Oxford Low Traffic Neighbourhoods (LTNs) located on St Marys, St Clements and Divinity Road.

Within the East Oxford LTNs, initial findings are:

• All locations monitored within the East Oxford LTNs showed a decrease in NO2 levels during 2022.
• Divinity Road saw the greatest reduction in NO2 levels by 33% (from 18ug/m3 to 12 ug/m3 - a 6ug/m3 decrease)
• Prince Street saw a 24% reduction in NO2 levels (from 17ug/m3  to 13ug/m3  – a 4ug/m3 decrease) 
• Within the St Marys neighbourhood LTN: Both Howard Street and Hurst Street saw a 19% reduction from 16ug/m3  to 13ug/m3 (a 3ug/m3 decrease)

With boundary roads, the initial findings are:

• Overall, boundary locations surrounding the East Oxford LTNs showed a mixed picture in pollution levels.
• Morrell Avenue saw a 19% reduction in NO2 levels (from 16µg/m3 to 13 µg/m3 – a decrease of 3µg/m3)
• Iffley road/Boundary Brook Road saw no significant change in air pollution levels (from 26ug/m3 to 27ug/m3)
• Cowley Road/Union Street showed a significant 37% reduction when compared to 2021 levels (from 30µg/m3 to 19 µg/m3- an 11µg/m3 decrease) - this is a return to pre-pandemic (2019) levels. This decrease is likely due to construction works taking place at Tesco Express during 2021 which concluded by 2022.
• St. Clement’s Street/The Plain - traditionally Oxford’s most polluted road - saw a 10% increase in air pollution levels, with a measurement of 43µg/m3 (from 39µg/m3 in 2021). This is slightly higher than the annual legal limit, however this remains lower than pre-pandemic levels at this site which recorded 53μgm3 in 2019.
• Cowley Road (James Street) saw the highest increase (35%) in NO2 levels  – from 20ug/m3 to 27ug/m3 (a 7ug/m3 increase) This likely due to vehicles diverted from the surrounding LTNs. However, despite the increase, pollution levels are below the city’s annual mean local target for NO2 and below the UK legal limit.

Last week, Oxfordshire County Council published its interim monitoring and evaluation report of the East Oxford LTNs which is available to read here.

Oxfordshire County Council is carrying out a full analysis of the LTNs over the summer which will be published to support the cabinet decision, expected in October, when a decision will be made on whether the LTNs should become permanent.

Zero Emission Zone Pilot

In February 2022, the two councils launched the UK’s first Zero Emission Zone (ZEZ) pilot in Oxford. Under the scheme, all petrol and diesel vehicles, including hybrids, will incur a daily charge if they are driven in the zone between 7am and 7pm unless they have a 100 per cent discount or exemption. 

The 2022 air quality report covers 10 months of the ZEZ pilot’s operation, during this period, air quality levels have:

Within the ZEZ pilot:

• Within the Zero Emission Zone pilot area – air pollution levels decreased overall during 2022.
• Cornmarket St saw a 14% reduction in air pollution levels (from 21µg/m3  to 18µg/m3  - a decrease of 3µg/m3)
• St Michaels Street saw an 18% reduction in pollution levels (from 17µg/m3 to 14µg/m3  – a decrease of 3µg/m3) - 2022 also saw the part-pedestrianisation of St Michael’s Street, which may have also contributed to a reduction in air pollution on this street.
• New Inn Hall Street saw a 12% reduction in air pollution levels (from 17µg/m3  to 15µg/m3  – a decrease of 2µg/m3)
• Queen Street and Bonn Square both saw no significant change in pollution levels, with a 1µg/m3 increase in NO2, which is within the margin of error.

Boundary roads:

• Boundary roads around the ZEZ pilot overall saw a reduction in air pollution levels.
• George Street (Magdalen Street side) saw a 12% reduction in air pollution levels (from 26µg/m3  to 23µg/m3  – a decrease of 3µg/m3)
• George Street (Gloucester Green side) saw an 8% reduction in NO2 levels (from 26µg/m3  to 24µg/m3  – a decrease of 2µg/m3)
• New Road saw no significant change in NO2 levels, with a 1µg/m3 increase in NO2, which is within the margin of error.
• Oxford High Street saw a 7% reduction in air pollution levels (from 38µg/m3 to 35µg/m3  – a decrease of 3µg/m3)
• St Aldate's saw no change from 2021 levels (33μg/m3)

Most of these areas are already heavily pedestrianised while they form part of the main city centre bus routes. Buses are the major emission source in these areas, so no major air quality improvements were to be expected in these areas at this stage. However, Oxford’s bus fleets have an agreed transition to electric buses – with 159 new electric buses expected to arrive in Oxford by spring 2024.

A full report on the impact of the Zero Emission Zone Pilot is expected to be published later this summer.

Particulate pollution (PM2.5 and PM10)

Particulate Matter (PM10 and PM2.5) saw no significant increase or reduction compared to 2021 levels. 

Monitoring air quality data

NO2 is measured in micrograms in each cubic metre of air (µgm3), with the legal annual mean target set by Government. The annual average is the most important assessment objective for NO2 across the UK, as it assesses the long-term levels of air pollution within an area.

Oxford City Council has a statutory duty to report on air quality within the city and gathers raw data from each monitoring station within the city, following detailed technical guidance from DEFRA.

Air Quality calculations are based on annual mean values to take into account monthly fluctuations due to seasons, weather changes and other outside influences, which can impact pollution levels. The Council’s reports are submitted to the Government to be ratified and approved.

The Council publishes annual air quality monitoring reports for the city every June, which are all freely available to read on its website.

National and local air quality targets

Air pollution has been found to particularly impact the most vulnerable members of society, such as those from minority backgrounds, the young, old and those experiencing health issues.

A 2016 report found that air pollution contributes to cancer, asthma, stroke and heart disease, diabetes, obesity, and changes linked to dementia. 

Across the UK, road transport is the largest source of NOX emissions in the UK, contributing 49% of total emissions in 2000. Similarly, according to Oxford’s most recent source apportionment study, transport is the largest contributor NOX emissions in the city – accounting for 68% of total emissions.

Last year, the World Health Organisation (WHO) published stricter guidelines recommending that the recommended limit for NO2 per year is reduced from 40µg/m³ to 10µg/m³ - citing that there is no safe level of air pollution.

In Oxford, the Council set its own voluntary target for 30µg/m3 of NO2 to be achieved, by 2025 at the latest. It is the first local authority in the UK to set its own city-wide target. This target goes beyond the current legal target set out by the UK Government of 40µg/m3, and aims to protect residents from harmful air pollution.

“We all know that air pollution is harmful to our health and to the planet. Our latest data has found that during 2022, air pollution levels reduced overall across the city, not only compared to 2021 data, but also compared to pre-pandemic levels - and despite an increase in traffic levels. However, there is ultimately no safe level of air pollution, and we must continue to take action to improve.”

Councillor Anna Railton, Cabinet Member for Zero Carbon Oxford and Climate Justice at Oxford City Council

“We are pleased to see Oxford City Council’s latest Air Quality Annual Report and its timely publication on Clean Air Day, especially as it shows improvement in the air quality across the city. The new electric bus fleet will take us even further towards the healthy streets we want to see.”

Councillor Duncan Enright, Cabinet Member for Travel and Development Strategy at Oxfordshire County Council