Northern Irelandâ€™s Department of Agriculture, Environment and Rural Affairs has confirmed that limits for nitrogen dioxide emission were breached at three sites during 2016 in its official air pollution report, published this month.
The report, which was published last week (5 December) and compiled by consultancy Ricardo provides details of air quality monitoring undertaken across Northern Ireland and gives a summary of 2016 results, as well as long-term trends.
Data was collected from 21 automatic monitoring stations in Northern Ireland for all, or part of, 2016. The data shows that air quality objectives for most key air quality pollutants were met in full, although objectives for nitrogen dioxide were not met at three sites that are close to busy roads.
According to the report, four sites exceeded the annual mean 40 Âµgm3 objective for NO2 concentration, including Belfast Stockmanâ€™s Lane (50 Î¼gm-3), Downpatrick Roadside (44 Î¼g m-3), Limavady Dungiven (44 Î¼g m-3) and Newtownabbey Antrim Road (41 Î¼g m-3).
However, the Limavady Dungiven site only captured around 14% of data for the year â€“ insufficient for a valid annual mean â€“ and was therefore not counted as one of the sites to have breached the limit value overall. All of the breaches were at traffic-related sites beside major or busy roads, the report claimed.
No sites exceeded the hourly mean limit value of 200 Î¼g m-3 on more than the permitted 18 occasions.
Fine particulate matter PM2.5 was monitored (using the FDMS analyser) at Belfast Centre throughout 2016, and at Londonderry Rosemount from 23 March 2016. Both sites reported annual mean PM2.5 concentrations below the EU Stage 1 limit value of 25 Î¼g m-3 (which had to be met by January 2015). Levels were also below the EU Stage 2 limit value (20 Î¼g m-3 to be achieved by January 2020).
Particulate matter PM10 was monitored at 13 locations in 2016, all of the sites met the limit value and objective of 40 Î¼g m-3 for annual mean PM10, and no sites exceeded the daily mean limit value and objective of 50 Î¼g m-3 on more than the maximum permitted 35 occasions during the year.
For Ozone, the report suggested that no sites exceeded the EU target value for human health of 120Î¼gm-3 (for the maximum daily 8-hour mean) on more than the permitted 25 days, or the more stringent AQS objective of 100 Î¼g m-3 on more than the permitted 10 days in 2016, although three sites had at least one exceedance day during 2016.
2016 Air Pollution in Northern Ireland