Air Pollution - Northern Ireland Air

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Air Pollution - Northern Ireland Air

Air Pollutionin Northern Ireland 2009


Air Pollution in Northern Ireland 2009Benzene was monitored at one site: Belfast Centre – whichmet the Limit Value in 2009.Polycyclic aromatic hydrocarbons (PAH) were monitoredat three sites in 2009: Ballymena Ballykeel, Derry Brandywelland Lisburn Dunmurry. In 2009, all three sites exceededthe Air Quality Strategy Objective for the PAH speciesbenzo[a]pyrene (which must be met by 2010).3.4 SummaryNorthern Ireland’s air quality continues to improve. Resultsfrom Northern Ireland’s network of air quality monitoringstations show that the EU Limit and Target Values, andcorresponding AQS Objectives, for the following pollutantshave been met by the due dates –• Carbon monoxide• PM10• Benzene• Sulphur dioxideNon-automatic monitoring in previous years also establishedthat ambient concentrations of lead were well within the limitand objective values.However, there remain a small number of sites close tobusy roads in the Belfast conurbation and in Newry thatdo not meet the Limit Values and AQS Objectives fornitrogen dioxide. Benzo[a]pyrene concentrations at LisburnDunmurry, Derry Brandywell and Ballymena Ballykeel werealso above the AQS Objective for 2010. Occasional ozoneexceedences (such as that which occurred at Derry in 2008)also remain a possibility.3.5 EyjafjallajökullOn 20 th March 2010, Iceland’s Eyjafjallajökull volcano beganerupting for the first time in 190 years. The main summiteruption of Eyjafjallajökull started on 14 th April, sending a plumeof ash and sulphur dioxide into the atmosphere. The size ofthe eruption itself was relatively weak, but the initial phasewas extremely explosive due to meltwater from the glaciercausing the magma to fragment into highly abrasive glassparticles which were thrown upwards in a plume to 13 km.Figure 3.3Images of the ash plume taken during April 2010Source: Icelandic Met Office, http://en.vedur.is/Following advice from the UK Met Office (the north-westEuropean Volcanic Ash Advisory Centre) UK airspace wasclosed for six days due to the risk of damage to aircraftflying through the plume. A significant reduction in NO xwasmeasured near some major airports during the period thatair space was closed 1 .There was concern that Eyjafjallajökull’s activity mighttrigger the eruption of a nearby and larger volcano, Katla- an occurrence last seen in 1821. However, this has nothappened to date.The Northern Ireland Air Quality Database and Websitewas a very valuable source of information to address publicconcern about possible air quality impacts, during thisdramatic event.1Barratt, B and Fuller, G “Preliminary analysis of the impact of airport closures due to the 2010 Eyjafjallajökull volcanic eruptions on local air quality”Available at http://www.londonair.org.uk/london/reports/volcano_airport_closures.pdf [Accessed 4 th Nov 2010].8


Air Pollution in Northern Ireland 2009UK were examined for any evidence of this. In the caseof Northern Ireland, PM 10data show two small peaks, thefirst around 11 th April, the second around 21 st - 24 th April.A few sites exceeded the 24-hour Limit Value of 50 µg m -3 .Peaks in daily mean PM 2.5concentration (data availablefrom Belfast Centre and Lisburn Dunmurry only – Figure 3.5)occurred at the same times. The second of these coincidedwith a small increase in ambient sulphur dioxide (Figure 3.6),which is also found in volcanic emissions.Figure 3.4NOAA HYSPLIT output showing the forecast movementof air masses from Iceland to Northern Ireland, the UKand Eastern Europe (as provided by NOAA website,http://ready.arl.noaa.gov/HYSPLIT.php )From April 14 th the volcano continued to erupt intermittentlyfor several weeks. Typically the dust plume from the volcanowas between 4km and 6km above sea level. On April 19 thIn Fig 3.5, would it be possible to mark with two labelledthe NOAA HYSPLITvertical linemodelthe “start offorecastthe eruption”thaton 20ththeMar 2010,ash plumeand the “start of the main summit eruption” on 10th Apr?might be driven over the UK. In certain meteorologicalconditions grounding of the plume could occur, increasinglevels of air pollution (sulphur dioxide and particulate matter)at ground level. Air quality monitoring data from around theAir mass back trajectories were such that the volcano couldhave contributed to the second peak. However, the FDMSinstruments used to monitor PM 2.5allow the measurementto be split into volatile and non-volatile components. BothApril peaks included some volatile material, which would notbe expected in volcanic ash. Also, a small peak in oxides ofnitrogen was observed: these arise from combustion sources,and their presence indicated that the particulate matter wasfrom combustion sources, rather than the volcano.So, there is no clear evidence that the volcano had animpact on ambient air pollution in Northern Ireland, althougha small contribution cannot be ruled out. The actual levels ofparticulate matter and SO 2during the relevant period werewithin the usual range, and were in fact lower than somedaily means measured in early March before the eruption.There is still much to be learned from the vast amount ofdata collected, and many organisations continue to carryout research into the volcanic eruption and its effects.Daily mean concentration of PM 2.5, µg m -3605040302010Start of theeruption002/03 09/03 16/03 23/03 30/03Start of the mainsummit eruption06/04 13/04 20/04 27/04 04/05 11/05 18/05 25/05 01/06KeyBelfast CentreLisburn DunmurryHigh SchoolDate (2010)Figure 3.5Daily mean PM 2.5at automatic sites in Northern Ireland March – May 2010 (the volcanic activity began on 20 th March).9


Air Pollution in Northern Ireland 2009Daily mean concentration of SO 2, µg m -33530252015105Start of theeruptionStart of the mainsummit eruption002/03 09/03 16/03 23/03 30/03 06/04 13/04 20/04 27/04 04/05 11/05 18/05 25/05 01/06Figure 3.6Date (2010)Daily mean SO 2at automatic sites across Northern Ireland, March – May 2010 (the volcanic activity began on 20th March).KeyAntrim Greystone EstateBallymenaCarrickfergus Rosebrook AvenueDerry BrandywellLisburn Dunmurry High SchoolStrabane Springhill ParkDerryLarne CraigyhillArds Leisure CentreBelfast CentreNorth Down BangorMean10


Air Pollution in Northern Ireland 2009Figure 4.2 shows annual mean concentrations of nitrogendioxide (NO 2) concentrations at urban background andkerbside/roadside sites. To avoid discontinuities due tochanges in the number (and distribution) of sites, eachaverage is based on a subset of long-running sites: theurban background average is based on Belfast Centreand Derry, and shown from 1998 (when the latter beganoperation). The kerbside/roadside average is based on sixlong-running sites, and is shown from 2004 only, when thenumber of such sites almost doubled. There are no cleartrends in nitrogen dioxide concentration for these sets oflong-running sites.35Annual Mean NO 2Concentration, μg m -3302520151998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009YearFigure 4.2Annual mean NO 2concentrations at long-running urban background and roadside sites in Northern Ireland, 1998-2009.KeyRoadside and Kerbside (Long-running sites,from 2004 only: Castlereagh Lough View Drive,Derry Dale’s Corner, Lisburn LVH, Newry TrevorHill, Newtownabbey Sandyknowes, North DownHolywood A2)Urban Background - Belfast Centre and Derry12


NO 2(µg m -3 )Air Pollution in Northern Ireland 20095Maps of Air QualityMeasurements from air qualitymonitoring sites in Northern Irelandhave been combined with pollutantemissions data from the UK’s NationalAtmospheric Emissions Inventory(NAEI) to produce detailed maps - at1km resolution - of average or peakbackground pollutant concentrationsacross the country for 2009.Figure 5.1 shows peak (99.9th percentile) 15-minute averageconcentrations of sulphur dioxide (SO 2). The main sourcesof this pollutant are industrial and domestic fuel burning -particularly coal and oil. While peak concentrations are verylow over most of Northern Ireland, there are still some smallareas of higher peak SO 2concentration around Derry andparts of the Belfast conurbation. There are also isolated “hotspots” of higher concentration throughout the rest of theregion, such as around Ballymena - possibly due to smallpockets of high domestic coal or oil use in small towns.Figure 5.2 shows corresponding annual mean PM 10concentration. Highest concentrations occur in the LaganValley, in the area around Belfast and Dunmurry. However,annual mean background concentrations throughout theregion are well below the Air Quality Strategy Objective.Like the other pollutants represented in these maps, estimatedbackground NO 2concentrations modelled for Northern Irelandin 2009 (Figure 5.3) are low. The highest concentrationsoccurred in the centres of Belfast and Derry. Also visible arethe major roads connecting Northern Ireland’s cities. Figure 5.4examines in greater spatial resolution NO 2concentrations inand around Belfast: this clearly shows the impacts of roadvehicle emissions on modelled NO 2concentrations.SO 2(µg m -3 )>200150-200100-15050-1001412-1410-128-102010-205-10


6Black CarbonConcentration of Black32100Air Pollution in Northern Ireland 20091 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23Hour BeginningBlack carbon is a measurement of airbornesoot-like particulate matter, based on anoptical absorption technique. Black carbonis typically formed in combustion processes.In the years before automatic PM 10monitoring becamewidespread, particulate pollution was often measured as“black smoke”, and a large UK network of monitoring sitesexisted until 2005. This has been replaced by a smallernetwork of monitoring sites (currently operated by theNational Physical Laboratory, NPL). The old-style “blacksmoke” samplers were replaced with new automatic blackcarbon analysers during 2008, allowing hourly monitoringand analysis of diurnal patterns.The fourth annual report 2 for this network, now renamed theBlack Carbon Network, covering 2009, is available on theUK Air Quality Archive at: http://www.airquality.co.uk/reports/cat05/1009031405_2009_BC_Annual_Report_Final.pdfThe Black Carbon Network includes three sites in NorthernIreland – at Belfast Centre, Lisburn Dunmurry, andStrabane. The annual mean black carbon concentrationsmeasured in 2009 were 2.1 µg m -3 at Belfast Centre (anurban centre site), 1.3 µg m -3 at Lisburn Dunmurry and1.6 µg m -3 at Strabane (the latter two sites are in residentialareas where domestic use of oil and solid fuels arewidespread). The annual mean for Belfast is similar tothat measured at sites in other urban centres such asGlasgow, Manchester, Stoke-on-Trent and Nottingham.(Note: data capture at Belfast was reduced to 59% due toequipment problems, and data rejection because of dustfrom nearby building work). NPL’s 2009 report investigateddiurnal variation (variation with time of day) in black carbonconcentration at all sites. Belfast Centre showed a patterntypical of urban centre sites in the Network: there was apronounced peak coinciding with morning rush hour traffic,and a broader evening rush hour peak extending into theevening. However, the diurnal patterns at Lisburn Dunmurryand Strabane were dominated by the evening peak. NPLattribute this to the domestic use of oil and solid fuels forhousehold heating. The differences in diurnal variationbetween the three sites are illustrated in Figure 6.1.Concentration of Black Carbon, μg m -3Concentration of Black Carbon, μg m -33.532.521.510.56543210000Figure 6.11 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23Hour BeginningStrabaneannualAs would be expected if this was the case, the eveningpeak is much more pronounced in winter, when fuel usageis greater. As an example, Figure 6.2 shows the diurnalvariation in black carbon concentration at Strabane, insummer (represented by the period April 1 st to September30 th 2009), winter (represented by the mean of 1 st Januaryto 31 st March and 1 st October to 31 st December 2009), andthe full year.1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23winterBelfast CentreannualDiurnal Variation in Black Carbon at Belfast Centre,Lisburn Dunmurry and Strabane, 2009.Figure 6.2Hour BeginningannualDunmurryannualsummerDiurnal Variation in Black Carbon at Strabane: summer,winter and full year.2D Butterfield, S Beccaceci, B Sweeney, D Green, J Alexander, A Grieve (2010) “2009 Annual Report for the UK Black Carbon Network” NPL Report AS 52,National Physical Laboratory Queens Road, Teddington, Middlesex TW11 0LW, ISBN 1754-2928. 3.5 Available on the Air Quality Archive at http://www.airquality.co.uk/reports/cat05/1009031405_2009_BC_Annual_Report_Final.pdf [Accessed 20 th Sep 2010].32.521.514f Black Carbon, μg m -3


Air Pollution in Northern Ireland 20097More informationThe website includes an interactive map showing whereNorthern Ireland’s automatic monitoring stations arelocated. By clicking on the map, users can view details ofeach monitoring site and current levels of the pollutantsmonitored. An ‘Air Pollution Index’ is used to provide asimple indication of current pollution levels. The website alsoincorporates an advanced Google Earth TM mapping feature,which allows users to “zoom in” on a site location, usingboth satellite photos or maps.2) Current and forecast air quality(national and local)This information is also readily available from:• the Air Pollution Information Service on freephone0800 556677;• the UK Air Quality Archive on www.airquality.co.ukFigure 7.1The Air Quality Website1) The Northern Ireland Air QualityWebsiteThe Northern Ireland Air Quality website, available atwww.airqualityni.co.uk provides information covering allaspects of air pollution in Northern Ireland. The site, fundedby the Department of Environment in Northern Ireland,provides information on;• latest up-to-date air quality levels across Northern Ireland;• reports and analysis of trends and historical data;• information on both national air quality policy and thework of Northern Ireland’s district councils;• descriptions of what causes air pollution, how it ismeasured, and relevant health, amenity and ecosystemimpacts.3) General information on Air QualityGeneral air quality information can be found at:• the DoENI website at www.doeni.gov.uk• The Northern Ireland Environment Agency website atwww.ni-environment.gov.uk• The UK Air Quality Information Archive onwww.airquality.co.uk• The National Atmospheric Emissions Inventory onwww.naei.org.uk• The Defra air quality information web resource onww2.defra.gov.uk/environment/quality/air/air-quality/4) Local Air Quality IssuesFor further information on air quality issues in your area,please contact the Environmental Health Department atyour local district council office. Further information on LocalAir Quality Management may also be found atww2.defra.gov.uk/environment/15


This report has been produced by AEA on behalf of the Department of the EnvironmentIts main authors are Alison Loader, Rachel Yardley and Dan Brookes. Maps by Justin Lingard and Ioannis Tsagatakis.© Cover image: Northern Ireland Environment AgencyISBN: 978-1-907053-16-0www.airqualityni.co.uk

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