Air quality monitoring

​​​​​​​​​​​​​​​​​​​​​​​​​​​​Nitrogen dioxide (NO2), Volatile Organic Compounds (VOC's) and Particle monitoring

Nitrogen Dioxide (NO2) is measured (in micrograms/m3 (per metre cube)) in real time at Beresford Street, Howard Davis Farm and at 20 sites around the Island using passive diffusion tubes which are sent off monthly to the UK for analysis. Diffusion tubes are also used to measure 4 VOC's (Benzene, Toluene, Ethyl Benzene and Xylene) at 5 other sites around the Island.

Particles (also known as particulate matter) are categorised as:

• total suspended particles TSPs
• PM10
• PM2.5
  

They're measured in real time at Beresford Street in St Helier in micrograms/m3. A second unit measures background particle levels in Howard Davis Farm.

NO2, VOCs and Particles are associated with traffic emissions and are potentially hazardous to health. Air quality in Jersey is generally good however there are increased levels of air pollution at hotspots such as in the tunnel and areas prone to congestion.

Data from the Departments real time particle analysers are shown in the graphs below. The data shown covers the latest 24 hours of reporting.

The results and analysis of this monitoring is published annually in a report by UK consultants Ricardo, Energy and Environment, the Air Quality Monitor​ing annual ​report 2023​.

Air Quality Index - PM₁₀ Particles

Health studies report that:

• when air pollution is 'Low' (1‐3) effects are unlikely to be noticed even by those who are sensitive to air pollution
• when air pollution is 'Moderate' (4‐6) sensitive people may notice mild effects but these are unlikely to need action
• when air pollution is 'High' (7‐9) sensitive people may notice significant effects and may need to take action
• when air pollution is 'Very High' (10) effects on sensitive people, described for 'High' pollution, may worsen​
  

Beresford Street 

Osiris Beresford Street monitor

This unit is a kerbside monitor and is sited close to Beresford Street so monitors particles from traffic sources. Spikes in particle pollution are generally due to vehicles leaving their engines running close to the monitor and traffic congestion on Beresford Street.​

Howard Davis Farm

​Osiris Howard Davis Farm monitor 

This unit is a background monitor moved to Howard Davis Farm on 28 June 2024 because of ongoing vandalism at the previous site.

Howard Davis Farm is a rural and background site but is within 70 metres of an animal cremator and a number of roads. It’s likely to be impacted by particles from natural sources such as wind-blown soil, sea salt, biological moulds and also from human sources such as domestic, incinerator and vehicle emissions.

You can find the Nitrogen Dioxide (NO2) data for Jersey on air pollution ​mon​​​itoring and particle data at other sites throughout t​he world is available on AirQ​Web.

Air quality monitoring sensor network

There are a number of air quality monitoring sensors sited in St Helier. These can be seen here:

You can see the current data on our Clarit​y Ope​n Map below.​ 

The sensors measure Nitrogen Dioxide (NO₂), Particles (PM10 & PM2.5), temperature and humidity. The interactive map displays the UK Daily Air quality Index (DAQI) for both PM2.5 and NO₂. It defaults to the highest DAQI result. 

Find out more information on the UK Daily Air Quality index at Defra UK.

The sensors in Jersey are sited on lampposts and signs in St Helier. The data collected can highlight trends and potential sources of pollution, but should not be used for comparison with UK, European Union health limits and World Health Organisation guide levels as they are indicative only.  Please note meteorological conditions can have significant effect on pollution levels.

​Air quality sensor sites​ 

Clarity Node sensors are located at:

• St Lukes school (Elizabeth St) 
• Helvetia (inside playground)
• Helvetia (Parade Road) 
• Robin Hood junction 
• Tunnel east entrance by Green Street roundabout
• Bottom of Mont Millais
• Beresford Street by market for calibration

Vortex Head sensors are located at:

• Rouge Bouillon school 
• Beaulieu School Wellington Road
• St Saviours Hill 
• Gloucester Street by gatehouse
• Beresford Street by market for calibration

Air quality in Jersey

Air quality in Jersey is generally good as it’s a windblown island with prevailing westerly winds, but elevated levels of localised air pollution do occur. For example, during periods of traffic congestion, particularly in canyon type streets and in the tunnel. 

​We have one of the highest car ownership levels, with Start of deleted contentover 175,000 vehicles End of deleted contentStart of added content127,911 vehicles End of added contentregistered to a population of approximately 112,000. There is no Ministry of Transport (MOT)​ vehicle test for cars at present, so this means older, more polluting vehicles are still being driven on the island, creating disproportionally high levels of air pollution.​​

Apps

Download the AirQApp application that displays results from environment sensors that collect particle levels in Jersey.

Air quality reports and documents

The Government of Jersey publishes air quality reports annually. These can be found below along with Jerseys Air Quality Strategy 2012, which sets out targets and objectives aimed at maintaining or improving the Air Quality on the Island, and the Air Quality Project Plan which details more specifically what actions are planned over the coming years.

These documents need updating and should complement the:

• Climate Change Strategy
• Carbon Roadmap
• Sustainable Transport Plan
  
• Bridging Island Plan

Report on Turnkey Osiris particle results at Beresford Street and Howard Davis Park sites

Air Quality Strategy 2012​​​​

Jersey Air Quality Project Plan

Vehicles emissions

This summary report presents a sample of the analysis of the real-world emissions measurements from vehicles in Jersey.

Report on vehicle emissions remote sensing in Jersey

Air quality in the tunnel

The short study includes a number of different assessments to evaluate:

• exposure of commuters traveling through the tunnel using different modes of transport 
• concentrations of nitrogen dioxide (NO2) in the tunnel 
• concentrations of nitrogen dioxide for pedestrians using al​ternative routes to work
  

Air quality monitoring in the tunnel, St Helier

Historical monitoring

We’ve been assessing and reporting on the quality of Island air since 1997.

​You can find previous air monitoring reports on States reports.​