​​This report presents the results for 2022 of an ongoing programme of air quality monitoring in Jersey, carried out by Ricardo Energy and Environment on behalf of the Natural Environment Department of the Government of Jersey.

The air quality monitoring programme in Jersey during 2022 consisted of:

• automatic monitoring of nitrogen dioxide (NO2)
• passive diffusion tube measurements for NO2 and hydrocarbons

An automatic monitoring station for (NO2) has been located in the Central Market, Halkett Place, St Helier since January 2008. In November of 2021 this was re-located to a new position to measure NO2 levels from traffic using Beresford Street. In addition, non-automatic diffusion tube samplers were used for indicative monitoring of NO2 at 23 sites, and a suite of 4 hydrocarbons (benzene, toluene, ethylbenzene and xylenes) at a further 5 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 tubes were supplied and analysed by Gradko International Ltd and changed by Technical Officers of Jersey’s Natural Environment Department. The 2022 non-automatic monitoring programme continued a long-term survey that has operated in Jersey since 1997.

During 2020 and 2021 the Covid-19 pandemic has affected the deployment and collection of the diffusion tubes, as well as a noteable change in measurements as a result of restrictions imposed. During 2022 the effects of the pandemic on this programme were felt less as there were no considerable changes to the diffusion tube calendar. All restrictions on the Island were removed by the beginning of 2022, and as a result concentrations and patterns seen in this report illustrate the continual recovery from the pandemic.

The automatic monitoring site at Beresford Street Market met the EC Directive limit value (and AQS objective) for the 1-hour mean NO2 concentration with 0 of 18 allowed 1-hour exceedances. The instrument achieved the 90% data capture required to create an annual average.

The 2022 period mean from the automatic monitor at Beresford Street Market was 17 μg m-3, lower than that recorded at the Halkett Place site in 2021(21 μg m-3).

Annual mean concentrations of NO2 did not exceed the EC Directive limit value of 40 μg m-3 at any of the diffusion tube sites. For comparison annual averages had a bias adjustment factor applied which gave lower annual averages for all sites. Diffusion tubes measure over a monthly period therefore, the results are an average and not applicable to measuring peaks or low levels of pollution at any specific time.

The diurnal variation in NO2 concentrations at Beresford Street Market showed some similarities to an urban site but had a particularly early (and sharp) morning rush hour peak, with a gentle but broad evening peak afternoon rush hour peak. This is thought to be due to traffic patterns around the site; this being early morning traffic associated with the market and use of the short term parking next to the site where drivers regularly leave vehicles running. Diurnal plots for Thursday show a flatter peak of lower magnitude compared to other weekdays, reflective of the market closing at 2PM on this day.

The pattern of monthly averaged concentrations throughout the year showed that concentrations of NO2 were typically highest in the winter months. Bivariate plots of NO2 concentration indicated that nearby sources, such as vehicles using Beresford Street, were probably the main source of NO2. There is also a source of NO2 seen to the southeast and southwest under windier conditions, possible sources include multiple main roads and the port.

Each of the hydrocarbon sites provided annual means below that required of the EC Directive limit value for benzene (5 μg m-3 as an annual mean, to be achieved by 2010). Since the introduction of catalytic converters in 1991 and the limiting of benzene concentrations in petrol to 1% in the year 2000, ambient measured concentrations have declined in the UK 1. The site at Harrington’s Garage measured the highest annual mean benzene concentrations, of 0.6 μg m-3, similar to the average at Faux Bie Terrace of 0.5 μg m-3. Both of these sites represents relevant public exposure near to petrol stations. Concentrations at Faux Bie Terrace which has been in operation since 2009 have decreased since a stage 2 vapour recovery system was installed in 2016.

Hydrocarbon concentrations were similar to 2021, except for ethylbenzene and xylene concentrations at Harrington’s Garage and Faux Bie Terrace where there was considerable increases (although still significantly below occupational exposure levels). 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 Market will be seen after these sites remain in operation for future years.