Oxford publish air pollution sources across the city

Oxford City Council have published a detailed report which reveals that domestic wood burning is the greatest source of PM2,5 in the city, while road transport has that dubious honour when it comes to NOx.

The Oxford Source Apportionment report, conducted by Ricardo, identifies the key sources of air pollution in the city.

The report is based on air pollution data measured in 2022 and modelling which has evaluated the impact of 159 electric buses which have taken to the city’s streets through the Government’s ZEBRA scheme. 

The main sources of NOx emissions were found to be: 

1. Road transport 32%
2. Domestic combustion 25.54%.
3. Point sources (eg: industry and commercial buildings) 19.74%
4. Other transport 8.9%
5. Non road machinery 7.11%
6. Industry combustion 3.38%
7. Rail 3%

The last time such research was undertaken, road transport was responsible for 40% of NOx emissions. The 8% point drop in this figure is credited to the introduction of the electric bus fleet.

Buses now contribute 4% to total NOx emissions, a 28% reduction from the previous Source Apportionment report.

The main sources of PM2.5 emissions were found to be: 

1. Domestic combustion 35.27%
2. Road transport 16.74%
3. Production processes 9.74%
4. Point sources 9.02%
5. Waste 8.2%
6. Other transport 6.75%
7. Solvents 4.54%

The domestic combustion figure is broken down further:

1. Wood burning 70%
2. Commercial heating (in businesses and institutions) 15%
3. Gas and coal 14%
4. Smokeless fuels 1%

Councillor Anna Railton, Deputy Leader and Cabinet Member for Zero Carbon Oxford, Oxford City Council said: ‘This latest source apportionment study shows us to the key sources of toxic air pollution in Oxford, and what areas we need to focus on to improve air pollution across the city.

‘We can see that there has been a significant reduction in the contribution of buses to NOX levels following the introduction of the 159 electric bus fleet. However, cars remain the largest contributor to this pollution.

‘The report also highlights that we must address the growing issue of domestic wood burning, which is now the largest source of harmful PM2.5 pollution in Oxford. Many people may not realise that even modern wood stoves produce dangerous emissions. By reducing wood burning and supporting zero-emission transport, we can continue to improve Oxford’s air quality for everyone.’

Councillor Andrew Gant, Oxfordshire County Council’s Cabinet Member for Transport Management added: ‘The modelled impact that the new fleet of electric buses is having on air quality in Oxford in such as short space of time is remarkable. We are incredibly proud to have put together the successful bid alongside the bus companies to bring them to the city, and this new report shows why it was such an important initiative in creating a cleaner, greener county.’

Luke Marion, Managing Director of Oxford Bus Company said: ‘We’re proud of the massive step change in emissions buses have delivered in Oxford over the last decade to help provide radically cleaner air for the communities we serve.

‘This has been sustained over several years with the move to ultra-low emission vehicles and more recently zero emission vehicles, following significant investment by both companies.

‘However, overall Oxford’s air is not benefitting as much as it could be due to the steadily increasing proportion of car and van emissions. The data clearly demonstrates that it’s vital for Oxford’s health that suitable measures are introduced to help reduce the volume of private vehicles on the city’s roads to achieve even greater improvements in air quality.’