Air pollution, housing and ULEZ

suspended wood flooring in the home

Road users around the UK will be familiar with ULEZ and the growing range of other acronyms concerning clean air zones. But should we consider a similar scheme for house building?

Why do we need clean air zones?

In what the European Commission described as “perhaps the longest running infringement of EU law in history”, the UK has failed to limit nitrogen dioxide levels under the EU Air Quality Directive.

Air pollution is a major contributor of preventable deaths in the UK, and is responsible for up to 36,000 extra deaths annually. Around 20% of childhood asthma in urban areas is due to nitrogen oxides. However, vehicle emissions are just one of the contributing factors.

What are the types of zone?

ULEZ (ultra-low emission zones), CAZ (clean air zones), and LEZ (low emission zones), are in place in various places to reduce air pollution in cities. They work by charging drivers of older or more polluting vehicles a fee for entering the zone.

The zones are based on the Euro emission engine classification standards, and vehicles meeting these standards are ‘compliant’ and do not attract the charges:

  • Euro 4 – for petrol cars and vans (generally registered from 2006);
  • Euro 6 – for diesel cars and vans (generally registered from September 2015); and
  • Euro VI – for buses, coaches and HGVs (generally registered from January 2013).

Non-complaint vehicles entering the zone are charged an entry charge and there are steep penalties for non-payment. The applicable charges and penalties vary between types of zone, as do the types of vehicles included and exemptions from the charge.

Where are Clean Air Zones in place?

There are currently Clean Air Zones in place in Bath, Birmingham, Bradford, Bristol, London, Portsmouth, Sheffield, Newcastle and Gateshead, where non-compliant vehicles are charged a daily entry charge ranging from £7 to £100 depending on city and vehicle type. Other schemes are under review, including Greater Manchester.

Do Clean Air Zones work?

In London, since the introduction of the ULEZ, inner city congestion has improved at a lower rate than expected. This is largely the fault of congestion and the increased level of pollutants emitted when vehicles brake and accelerate compared to when they travel at a steady rate. As a result, there remains little difference in air quality between the inner city and outer boroughs, which have pollution levels far in excess of World Health Organisation standards.

Experts say that, in any case, around half of the polluting nitrogen dioxide gas comes from buildings, not vehicles, produced by houses, offices and industrial buildings and, to really improve the quality of air people breathe, a similar scheme is needed for buildings.

Why are buildings a problem?

Many of our heat and power sources produce significant amounts of nitrogen oxides. One of the problems is the domestic gas boiler which creates emissions equal, on average, to taking a new diesel car on a 43 mile drive.

Changing our wood burners, gas and oil burning boilers to other heat sources may not improve the situation. The process of creating hydrogen, for example, causes the natural nitrogen molecules found in air to break apart, forming nitrogen oxides. In the future, it may be possible to limit the pollution produced in creating hydrogen, but such measures are not yet available.

How might a ULEZ for homes be regulated?

The way that buildings are heated produces most nitrogen dioxide and the problem could be addressed by the installation of electric heating or cleaner boilers, and improvements to insulation. The poor management of buildings is also a contributing factor and a building with a poorly maintained heating or ventilation system is more likely to produce air pollutants.

Building regulations and planning laws do not yet address these issues and experts are calling for a policy of retrofitting and regulation, with local controls in place in the same vein as ULEZ.

Critics suggest that, instead of ULEZ, the government and house builders should be made more responsible, and that new buildings should be made more eco-friendly. The government’s own Chief Medical Officer said in its 2022 Annual Report that: “a critical engineering challenge is getting the best solution for maximising ventilation, while keeping buildings warm in winter and cool in summer, and minimising energy and therefore carbon use.”

How can we reduce air pollution within the home?

The majority of air pollution inside our homes comes from using everyday items, not from roads. A report by Airtopia for Clean Air Day analysed 47 homes across England and reported dangerous levels of air pollution.

Formaldehyde – An excess of formaldehyde was found in 20% of the homes, and in 13% the properties had levels above World Health Organization recommendations. Formaldehyde can cause cancer and is found in a variety of domestic situations including some adhesives, paints, varnishes, carpets and furniture items.

Radon – Another dangerous gas found was radon, which generates radioactive dust that can amass within the home and accounts for over a thousand lung cancer deaths every year in the UK.

Volatile Organic Compounds (VOCs) – Air fresheners cause VOCs and an excess of this substance was found in 45% of homes; 17% had very high levels of VOCs. VOCs can cause respiratory problems, cancer, and liver damage, and are contained in some perfumes, cleaning products, shower gels, adhesives, and (perhaps ironically) in air fresheners.

Gas Cooking – Gas cooking can cause pollution levels within the home to increase 5,000% over outside levels, and take several hours to dissipate without proper ventilation.

Wood Burners – In the UK, wood burners produce three times more pollution than vehicles. They produce fine particle air pollution and significantly contribute to pollution in households. Wood burning is limited in smoke controlled areas where only smokeless fuel can be used, including anthracite coal. Wood burners are eco-rated from A++ to G, and the highest rated burners produce fewer pollutants which can escape via the chimney. More polluting wood burners or those with a poor supply of oxygen will create more smoke.


With regulation sadly lacking, raising public awareness to the dangers that lie within households is one way of improving air pollution. Many of the products we use have low pollutant options, which give home owners the ability to protect themselves from these threats.


A Clean Air Bill is to be passed this year after House of Lords approval of the Clean Air (Human Rights) Bill. The new law would ensure government checks of pollution levels that will improve air quality in the UK, reaching World Health Organisation standards within five years, and give people the right to breathe clean air. It would also ban the installation of gas boilers in new homes from 2025.