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Air quality

Good air quality is important for our health and quality of life.


- Air quality

- Annual air quality report

- Air Quality Management Area (AQMA)

- Current air quality

- Live monitoring station data

- What Uttlesford is doing to promote improvements in air quality

- Regulation of air quality

- Air pollution

Air quality

Air quality  in Uttlesford is determined by many factors, including traffic exhaust, emissions from local industry, and domestic sources. 

The Environmental Health service monitors air quality under the framework for local air quality management  set out in the Environment Act 1995, to assess whether national air quality objectives contained in the  government's  National Air Quality Strategy are being met. Air Quality standards are set for the following pollutants which are known to cause harm:

  • Sulphur dioxide
  • Nitrogen dioxide
  • Benzene
  • Particulate matter
  • Lead
  • Carbon monoxide

National Air Quality Objectives

The National Air Quality Objectives are set out in the Air Quality Standards Regulations 2010 on for the purpose of local air quality management.

For the protection of human health



Averaging period


5.00 µg/m3

Annual mean

Carbon monoxide

10.0 mg/m3

Maximum daily running 8-hour mean


0.5 µg/m3

Annual mean

Nitrogen dioxide

200 µg/m3 not to be exceeded more than 18 times a year

1-hour mean

40 µg/m3

Annual mean

Particles (PM10) (gravimetric)


50 µg/m3, not to be exceeded more than 35 times a year

24-hour mean

40 µg/m3

Annual mean

Sulphur dioxide

350 µg/m3, not to be exceeded more than 24 times a year

1-hour mean

125 µg/m3, not to be exceeded more than 3 times a year

24-hour mean

Particles (PM2.5 )

25 µg/m3 to be achieved by 2020

Annual mean


100 µg/m3 : not more than 10 annual exceedances

Daily 8hr mean


For the protection of vegetation and ecosystems



Averaging period

Nitrogen oxides

30 µg/m3

Annual mean


Note: µg/m3 = microgram per cubic metre

Where national targets are not being, or are unlikely to be achieved, the local authority must declare an Air Quality Management Area (AQMA) and implement an Action Plan. Most AQMAs are declared as a result of nitrogen dioxide from road vehicle emissions.

Annual air quality report

Our 2023 Annual Status Report (ASR) (PDF) [4MB] is designed to provide the public with information relating to local air quality in Uttlesford, to fulfil Uttlesford District Council's statutory duty to review and assess air quality within its area, and to determine whether or not the air quality objectives are likely to be achieved.

In 2022, Uttlesford District Council measured no exceedances of the Air Quality Objectives.

Air Quality Management Area (AQMA)

Uttlesford declared an AQMA in May 2012 to include major road junctions in Saffron Walden, based on the annual mean for nitrogen dioxide not being met at the Debden Road/London Road junction and the Thaxted Road/East Street junction. The area was centred on Elm Grove off Hill Street.

On 19 March 2024 the Saffron Walden AQMA was revoked.

Order Revoking an Air Quality Management Area: Saffron Walden (PDF) [270KB]

Current air quality

Information on current air quality including the five main pollutants that can cause material health effects is provided using an index produced by the Department for Environment Food & Rural Affairs (Defra) called the Daily Air Quality Index, which can be viewed on the Air Information Resource page on the Defra website.

Local air quality monitoring data

Air quality monitoring is undertaken at two automatic monitoring stations located in Saffron Walden, and currently at 39 other sites throughout the district using diffusion tubes.

Live air quality monitoring data

You can see the current real time air quality at our 2 automatic monitoring stations at:

All times shown are GMT.

Nitrogen dioxide

All combustion processes in air produce oxides of nitrogen, including nitrogen dioxide (NO2) and Nitric Oxide (NO). Road transport is the main source, followed by the electricity supply industry and other industrial and commercial sectors. NO2 is associated with adverse effects on human health. At high levels NO2 causes inflammation of the airways, and long term exposure may affect lung function and respiratory symptoms. NO2 also enhances the response to allergens in sensitive individuals.

Nitrogen dioxide Automatic Monitoring Data

Over the past 11 years the data for Uttlesford shows no exceedances of the annual mean NO2 objective at the automatic monitoring sites.

In the years when the hourly mean was exceeded, the number recorded was well within the number acceptable to meet the 1 hour standard (200µg/m3 not to be exceeded more than 18 times/year).

Diffusion tube monitoring data

During 2023 nitrogen dioxide was monitored at 75 sites using diffusion tubes. No exceedances of the Annual Mean objective were found for the seventh year running and the previous Air Quality Management Area in Saffron Walden was revoked in March 2024.

It should be noted that a number of the diffusion monitoring tubes are situated immediately alongside the carriageway. These are located on street furniture for practical reasons and as a result they are exposed to higher levels of emissions than the neighbouring houses.

Results of NO2 diffusion tubes

Full details of the latest results can be found in the 2023 Annual Status Report (ASR) (PDF) [4MB] .

Particulate Matter

Particulate Matter (PM) is categorised on the basis of the size of the particles.

PM10 consists of particles less than 10 micrometres in diameter, and PM2.5 consists of particles with a diameter of less than 2.5micrometres in diameter. Exposure to Particulate Matter (PM) is associated with respiratory and cardiovascular illness and mortality. The finer the particle, the greater the risk of inhalation deep into the respiratory system with associated ill health effects.

PM is made up of a wide range of materials and arise from a variety of sources. Concentrations of PM comprise primary particles emitted directly into the atmosphere from combustion sources and secondary particles formed by chemical reactions in the air. PM derives from both human-made and natural sources (such as sea spray and Saharan dust). In the UK the biggest human-made sources are stationary fuel combustion and transport. Road transport gives rise to primary particles from engine emissions, tyre and brake wear and other non-exhaust emissions. Other primary sources include quarrying, construction and non-road mobile sources.

Uttlesford District Council monitors PM2.5 concentrations at two locations across the district using one BAM 1020 reference monitor and one Osiris particle monitor. No exceedances of the Annual Mean objective have been found.

PM 10 continues to be monitored at the automatic station located at London Road, Saffron Walden. No exceedances of the Annual Mean objective have been found. Exceedances of the 24-hour mean have been recorded but are well below the AQS maximum number permitted of 35 per year.


Generally air quality in Saffron Walden remains good with a low likelihood of any serious impacts on health. However the Council is not complacent and regards air quality as an important aspect affecting the quality of life within the town and district. It is keen to ensure that air quality does not deteriorate in the future nor that it should be adversely affected as a result of new developments.

Future developments

Certain larger proposals for development which may affect air quality in the district need to be supported by an Air Quality Impact Assessment and provide for mitigation measures where necessary, to ensure there is no worsening of the air quality.

In addition to junction improvements and other proposed mitigation measures, the introduction of revised EU wide emission controls for vehicles produced from 2013 onwards is expected to contribute to improved air quality within the town to reduce the likelihood of further exceedances of the AQSs.

What Uttlesford is doing to promote improvements in Air Quality

An Action Plan has been developed, and following a period of statutory consultation, was adopted by Cabinet in October 2017.

Air Quality Action Plan 2017 - 2022 (PDF) [1MB]

A key measure is traffic management and other physical intervention like cycle routes, and development of the plan has been dependent upon input from Essex County Council Highways officers. Other measures focus on behavioural change and modal shift towards sustainable forms of transport, and ensuring a consistent and integrated approach towards development control, through policies and technical guidance to developers.

An annual review of the plan will be undertaken to assess progress of implementing the measures and to ensure the proposed actions remain appropriate. Progress each year will be reported in the Air Quality Annual Status Report as part of our statutory duties set by Defra.

The plan has the co-benefit of reducing exposure to fine particulates, a duty which Defra has placed with local authorities due to the known health impacts.

Apart from the Action Plan measures, Uttlesford continues to enforce legislative controls to reduce emissions throughout the district, and to provide public information and guidance on air quality issues.

Regulation of Other Air Quality

1. Industrial Emissions.   The Pollution Prevention and Control Act 1999 requires that  operators of certain industrial processes apply to either the Environment Agency or a  local authority, depending on the nature of the process, for a permit to control air and other emissions. UDC permits 26 processes which are inspected at least annually to ensure compliance with the conditions of their permit. Processes permitted by local authorities are divided into two categories - those that have the potential to impact on air, land, water and the noise environment, called part A2 processes, of which there are two in Uttlesford. These permits also control other matters including waste management and energy efficiency.  The remainder, called part B processes, are considered to impact only on the air, and include facilities such as larger petrol stations, users of solvents, concrete crushers and cement batching. Operators are required to comply with conditions which are deemed to meet best practical techniques available for controlling emissions. Failure to do so can result in legal action being taken.     

View the list of all sites holding a permit as at April 2022 on the LAPPC Environmental Permitting Register (PDF) [175KB]  

Further information on the processes can be obtained by contacting the Environmental Health Section

2. Statutory Nuisance. The Environmental Protection Act 1990 defines a number of Statutory Nuisances including bonfires, dust , fumes and gases emitted from premises. Where a local authority is satisfied that a statutory nuisance exists, is likely to exist or recur, it must serve a Notice on the person responsible to require abatement of the nuisance. Failure to comply with the terms of the Notice may result in prosecution. We have put together some information on bonfires.

3. Dark Smoke.  The Clean Air Act 1993 regulates emissions of dark smoke from  chimneys and  from industrial or trade premises

4. Chimney Heights. The Clean Air Act 1993 requires local authorities  to approve the height of chimneys from certain processes to ensure satisfactory dispersal of  emissions into the atmosphere.

Air pollution

People in good health usually encounter no serious short term side effects from moderate levels of air pollution. However elevated levels and/or long term  exposure to pollution can affect human health, ecosystems and buildings. People with lung or heart conditions are at greater risk, and asthmatics may find poor air quality triggers attacks or leads to increased use of inhalers.

Further information can be found on our Air Pollution - information on prevention and control page.


Additional information

2022 Annual Status Report (ASR) (PDF) [1MB]

2021 Air Quality Annual Status Report (ASR) (PDF) [1MB]

2020 Air Quality Annual Status Report (ASR) (PDF) [2MB]

2019 Air Quality Annual Status Report (ASR) (PDF) [1MB]

►  2018 Air Quality Annual Status Report (ASR) (PDF) [1MB]

►  2017 Air Quality Annual Status Report (ASR) (PDF) [1MB]

2016 Air Quality Annual Status Report (ASR) (PDF) [2MB]

Updating and Screening Assessment (USA) 2015 (PDF) [2MB]

Air Quality Progress Report 2014 (PDF) [2MB]

Air Quality Progress Report 2013 (PDF) [2MB]

Updating and Screening Assessment (USA) Report 2012 (PDF) [1MB]

► Further information about air quality in the county is available from Essex Air