​The average nitrogen dioxide (NO₂) concentrates are measured on a monthly basis at 22 air quality monitoring sites in Jersey and this indicator monitors the number of times measurements taken of average NO₂ concentrates were above EU Directive limits. The range the indicator covers is from 0 (no breaches) to 264 (22 sites breaching 12 months of the year).

Typically, around 90% of the 22 monitoring sites have no breaches and Jersey’s air quality typically meets international standards for over 90% of the year, thanks to the Island’s prevailing weather and the absence of major industrial activity. Breaches can occur, however, when a change in weather patterns over a period of time results in higher pollution levels than usual in that area. Breaches can also be contributed to by high levels of road traffic.