​​This report presents the results for 2024 of an ongoing programme of air quality monitoring in Jersey, carried out by Ricardo on behalf of the Natural Environment Department of the Government of Jersey.

The air quality monitoring programme in Jersey during 2024 consisted of the following:

• Automatic monitoring of nitrogen dioxide (NO2)
  
• Automatic monitoring of particulate matter (PM10 and PM2.5)
  
• Passive diffusion tube measurements for NO2 and hydrocarbons
  

A suite of four hydrocarbons, benzene, toluene, ethylbenzene and xylenes, at a further five sites. Hydrocarbon monitoring sites included areas likely to be affected by specific emission sources, such as a petrol station and a paint spraying process, as well as general background locations.

The 2024 non-automatic monitoring programme continued a long-term survey that has operated in Jersey since 1997. In 2025, the particle Osiris monitors are planned to be replaced with low-cost sensor units, and a new reference site is planned to be installed in Jersey which will include a reference PM analyser.

Since 2000, there is shown to be an overall decreasing trend in NO2 concentrations at long-running NO2 diffusion tube monitoring locations. This decrease is likely linked to increased vehicle efficiency and cleaner fuels as well as the overall decline in the use of diesel vehicles in Jersey.

A few sites showed small increases in NO2 concentrations in 2023 which is likely due to the continued reuptake in travel following the COVID-19 Pandemic restrictions imposed between 2020 and 2021. However, in 2024, all diffusion tube monitoring sites showed a decrease in concentrations in 2024 compared to 2023.

Over the long term, hydrocarbon concentrations have generally decreased at all sites that have been operational for 5 years or more.

Long term trends at Rue de Pres and Beresford Street will be seen after these sites remain in operation for future years.