Contact Details: Air Quality

Since 1 May 2019, Watford Borough Council has been providing certain air quality services on behalf of Three Rivers District Council, such as the regulation of dry cleaners, crematoria, timber processes, etc. and providing local air quality management services. 

The council will only be involved in emissions from certain businesses under Local Air Pollution Prevention and Control (LAPPC) controls.

Find out more here:

For nuisances from domestic premises, please contact the Residential Environmental Health team at Three Rivers via our Online contact form.

In keeping with other local authorities, Three Rivers are legally obliged to monitor air quality in the district and to review and report the data annually to the Department for Environment, Food & Rural Affairs(DEFRA). Annual status reports (ASRs) are undertaken by specialist officers to consider all monitored data, existing AQMAs (Air Quality Management Areas) and any changes in the district since the last ASR such as new developments, infrastructure proposals, and polluting industry that could have an impact on air quality.  

Once DEFRA have formally agreed the returns and any further work potentially required the information is made publically available.

The Air Quality Objectives in England require the council to consider various pollutants. The main areas identified for considerations due to local sources are nitrogen dioxide and particulates. Sulphur dioxide for example is normally associated with heavy industry such as electricity generation, there are no known significant local sources of SO2 and therefore this is not monitored by the council. The main source of local pollution in Three Rivers district is from vehicles, both nitrogen dioxide and particulates are released from vehicle sources.

The district council currently monitor Nitrogen Dioxide (NO2) by diffusion tubes. The tube locations have been historically identified and sited in areas where it is most likely that the air quality objectives could be exceeded. Officers also need to consider relevant receptors i.e. dwellings, schools, care homes. Officers decide the locations based on the annual monitoring and available data such as traffic counts and queuing data.

There is also monitoring at a limited number of locations where there is limited pollution to provide background measurements. If monitoring identifies a potential exceedance then a local authority must carry out further investigations, this may be further monitoring or a Detailed Assessment, if this still shows that the objective levels are likely to be exceeded an Air Quality Management area shall be declared and an Action Plan drafted/Reviewed. All monitoring data, Annual Status Reports, Detailed Assessments and Action Plans are required would be sent to DEFRA for consideration.

The council has tubes located in various locations around the district and report this annually to DEFRA as part of the ASR, details can be found here including locations of the diffusion tubes:

The location of the diffusions was last reviewed in late 2021/22.  Subsequently there has been a change in tube location and a 12 additional tubes have been added, see details in the 2021/22 ASR. This has been in response to review of relevant data. 

The council reports and monitoring data can be seen at

The Hertfordshire and Bedfordshire Air Pollution Monitoring Network provides up-to-date local air pollution information.


Town Hall
Hempstead Road
WD17 3EX