3Air Quality
Nitrogen as an Air Pollutant: Ammonia and Nitrogen Oxides
61.Nitrogen plays a role in air pollution primarily through two of its forms - ammonia and nitrogen oxides. Ammonia emissions from agriculture contribute to acidification of water sources with a devastating effect on biodiversity,150 and have a deleterious impact on fauna and fungi.151 Ammonia can also combine with other forms of air pollution such as nitrogen oxides released by transport, industrial and household activities and sulphur dioxide from industry, and contribute to the formation of airborne fine particulate matter (also called PM2.5), with strong negative impacts on human health.152 This Committee has looked at the health impact of nitrogen oxides as part of its work on air quality.153 Nitrogen oxides,154 particulate matter (PM), and ozone (O₃) cause a range of health problems, including: adverse impacts on lung function and lung growth, respiratory problems, asthma prevalence and incidence, cancer, heart disease, adverse birth outcomes and mortality.155 Nitrogen dioxide, one of the nitrogen oxides, and particulate matter causes an estimated 40,000 early deaths every year,156 and has been estimated to cost the UK up to £19 billion annually.157 Another nitrogen oxide, nitrous oxide, is a potent greenhouse gas; it has a global warming potential 298 times greater than carbon dioxide,158 and cause acidification and eutrophication of water ecosystems.159
Sources of Ammonia, Nitrous Oxide and Nitrogen Oxides
62.The agricultural sector is responsible for about 88 percent of the UK’s ammonia emissions,160 and emissions from dairy farms have doubled over the past 10 years.161 We heard evidence that ammonia emissions may have increased due to the use of anaerobic digestate and spreading of urea fertilisers as opposed to ammonium nitrate-based fertilisers.162 In terms of nitrous oxide (N₂O), the agriculture sector dominates: emissions from agricultural soils in 2016 account for 53% of total UK emissions, and other agricultural sources (i.e. management of waste and manure and field burning) add another 13%.163 Other important sources in recent years include road transport, other fuel combustion sources and waste processes.164
63.In 2016, almost all nitrogen oxides emissions (99%) came from the burning of fuels: 34% for road transport, 23% for other forms of transport (including off-road vehicles and mobile machinery), 22% from power stations and other energy producers, and 12% from other industrial sites.165
Air Quality Regulation
64.Air quality is regulated by several EU Directives. The EU’s 2016 National Emission Ceilings Directive sets national ‘ceilings’ for air pollutants, including nitrogen oxides and ammonia. The EU’s 2008 Ambient Air Quality Directive sets limits for concentrations of pollutants in the air, including nitrogen dioxide, particulate matter, fine particulate matter, sulphur dioxide, lead, carbon monoxide and benzene.166 As air quality is a devolved matter, separate legislation exists for Scotland, Wales and Northern Ireland.167 Local authorities are required to regularly review and assess air quality in their areas and if national limits risk being breached the local authority concerned must declare an air quality management area (AQMA) and prepare an air action plan.168 The UK is divided into 43 air quality zones for the purposes of monitoring and reviewing air quality.
65.Other relevant directives include the Industrial Emission Directive (IED) and the Medium Combustion Plant Directive which target emissions, including nitrogen oxides. See Annex 3 of this Report for further detail on these two Directives and transposing legislation.
66.The Committee on Climate Change monitors and reports on emissions of nitrous oxide as part of its work scrutinising the Government’s progress towards meeting its carbon budgets and international commitments, such as the Paris Agreement.169 There Government provides guidance regarding the control of emissions and a system of permits which businesses must obtain if their activities are likely to produce emissions.170
Performance on Reducing Nitrogen Oxides and Ammonia Emissions
Nitrogen Oxides
67.Emissions of nitrogen oxides in 2016 had fallen by 72 per cent since 1970 to 0.89 million tonnes. Between 2015 and 2016, nitrogen oxides emissions decreased by 10% (see graph below):171
68.These overall reductions in nitrogen oxide emissions have included reductions in nitrous oxide emissions. Emissions from this greenhouse gas reduced from just under 170 kilotonnes in 1990 to just over 72 kilotonnes in 2016.172 This has been achieved by closures of industrial units, industrial abatement installations and a decrease in the use of synthetic fertilisers.173 However, the Committee on Climate Change (CCC) has warned that reductions since 2008 have flatlined. This includes agriculture, where emissions have remained almost constant since 2008, though in 2016 emissions were 2% higher than those in 2008.174 The CCC stated that if the Government is to make further progress in hitting its Carbon Budgets, it will need to bring about further reductions in nitrous oxide emissions, including those from agriculture. It said that the latter can be achieved by better linking farming support to emissions reduction by addressing areas such as nutrient and waste and manure management.175
69.Despite the overall reduction in nitrogen oxides, the UK is still breaching the EU-limit on nitrogen dioxide (NO₂) concentrations. The National Audit Office’s report ‘Air Quality’, published in November 2017, found that over 86% of air quality zones in the UK (37 of 43 zones) did not meet nitrogen dioxide limits in 2016.176 In May 2013 the UK Supreme Court had ruled that EU Air Quality Directive limits on nitrogen dioxide had been regularly exceeded in 16 zones across the UK and that air quality improvement plans had estimated that in London compliance with the Directive’s standards would only be achieved by 2025 and by 2020 for the other 15 zones (the original deadline in the Directive was for compliance by 2010).177 The European Environment Agency has also produced analysis which indicates that the UK has the second highest premature death rate from nitrogen dioxide in the EU, second only to Italy.178
70.The UK Government has been referred to the European Court of Justice for failing to meet EU air quality standards, including action on nitrogen dioxide emissions.179 It has also been challenged in UK courts through Judicial Review by private organisations, including ClientEarth, several times between 2015 and 2018. This included review of the Government’s postponement of reaching compliance with air quality limits and subsequent air quality plans for tackling nitrogen dioxide pollution.180 The last ruling, in February 2018, was that the latest government plan was “unlawful” and that more action was needed in 45 English local authority areas and in Wales.181 The Judge said that ministers had to ensure that in each of the areas, steps were taken to comply with the law as soon as possible.182 The EAC, along with the Health, Transport and Environment, Food and Rural Affairs Committees set out a number of recommendations for dealing with the nitrous dioxide problem, primarily in terms of road transport.183
Ammonia
71.Since 1980, ammonia emissions have fallen by 10%, although they have increased in recent years:184
72.The Government accepts this is an issue to be addressed, especially because of the impact such emissions are having on wildlife and habitats.185 While ammonia emissions have grown, emissions of particulate matter have fallen: PM2.5 emissions fell 3.7% in 2016 to the lowest level on record, while emissions of larger particles known as PM10 were down by 1.9% over the year.186 In 2016 ammonia emissions from agriculture, which accounts for 88% of total emissions was made up of:187
UK agriculture ammonia emissions (2016) by livestock and fertiliser category
73.In terms of comparing UK ammonia emissions with the rest of the EU, the graph below shows how the UK compares with other EU countries in terms of ammonia emissions from utilised agricultural land in 2015:
Aggregated emissions of agricultural NH3 per utilised agricultural area (kilotonnes per million ha), 2015, EU-28
Source: European Environment Agency, Agri-environmental indicator - ammonia emissions, (2017).
74.We have commented elsewhere on the Government’s failure to meet air quality standards on nitrogen oxides, especially in relation to transport. We welcome progress on reducing particulate matter but we are disappointed that after many years of reductions in ammonia emissions they are beginning to rise. The Government has accepted that this is an issue that needs addressing. We would note that agriculture contributes 88% of ammonia emissions and nearly half of which are from cattle and about a quarter are from fertiliser applications. These are key areas where the Government needs to focus if recent rises in ammonia emissions are to be reversed and reductions made.
The Environment, Food and Rural Affairs Committee Air Quality Report (2016)
75.When the Environment, Food and Rural Affairs (EFRA) Committee looked at the issue of air quality in 2016,188 it concluded that the Government needed to do more to help farmers to adopt modern practices that cut emissions of greenhouse gases and local air pollutants including ammonia and that better use should have been made of Common Agricultural Policy funding to achieve air quality improvements.189 It also noted a divergence of opinion on whether regulation or voluntary action was the best way to tackle emissions. The EFRA Committee received evidence that suggested that regulatory approaches in the Netherlands and Denmark had, despite farmers’ complaints,190 changed the sector’s thinking and driven best practice. The EFRA Committee heard that that there were a wide range of technical options to reduce emissions such as improved systems for fertiliser application and manure handling and storage. For example, emissions could be reduced by avoiding the use of urea in fertiliser, by optimising the level of nitrogen in feed and by injecting slurries or ploughing manures into soils rapidly.191
The Government’s Clean Air Strategy
76.The Government’s 25 Year Environment Plan, published in January 2018, set clean air as a key goal and committed the Government to publishing an air strategy.192 The Government published its draft Clean Air Strategy in May 2018.193 It stated that it would invest in improved modelling and analysis of air quality and bring together national and local data.194 It would seek progressively to cut public exposure to particulate matter and halve the population living in areas with concentrations of fine particulate matter above WHO guideline levels (10 µg/m3) by 2025.195 There would be better air quality information for the public and organisations; and coordination across Government to ensure a joined-up approach to tackling air pollution. There would be more investment and support for clean technologies across the transport, energy, industry and agriculture sectors.196 This included ending the sale of new conventional petrol and diesel cars and vans by 2040 and support for vehicles with zero exhaust emissions, which would help reduce the impact of nitrous oxides.197
77.The strategy also sets out specific proposals for farming. It proposes a national code of good agricultural practice to control ammonia emissions,198 to require and to support farmers to make investments in farm infrastructure and equipment that will reduce emissions through better management and storage of slurry and improved use of anaerobic digestate.199 It proposes to improve the UK’s ammonia inventory to ensure emissions are captured accurately and is considering extending IPCC (UN Intergovernmental Panel on Climate Change) emission permits to dairy farmers (currently applied to pigs and poultry farms) and is also looking at the mandatory use of urea inhibitors,200 alongside urea fertilisers.201 In September 2018, the Government announced a £3m scheme to help farmers reduce ammonia emissions as part of its Clean Air Strategy.202
Reaction and Comment on the Clean Air Strategy
78.Several witnesses commented on the Strategy. The Country Land and Business Association told us they support the use of urea inhibitors.203 Others thought that the proposals should go further and supported a tax on nitrogen to reduce emissions and nutrient leaching.204 Several witnesses were concerned as to whether some of the proposals would be economically feasible for farmers and land managers, especially in the timeframe suggested by the Government, such as investment in farm infrastructure or reductions in fertiliser use.205 For instance, we were told that the typical cost of a steel slurry store for 100 cows was about £60,000 and that such stores often faced planning issues.206 There was therefore support for schemes and financial incentives for famers to achieve policy goals in the areas of healthy soils and water and air quality.207 Others thought that the Government needed to consider the nitrogen cycle as a whole and the interaction between nitrogen applied to the land, or produced from animal waste and released into the air and absorbed into water systems and back into soil.208 They suggested that this pointed to the need for a joined-up approach in terms of air, water and soil quality regulation, regulators and best practices.209 While a number of witnesses supported increased use of anaerobic digestion to dispose of farm and food waste,210 others were concerned that poor handling, storage and disposal of anaerobic digestate was increasing ammonia emissions.211
79.We welcome the Government’s acknowledgement that both nitrogen oxides and ammonia are key air quality problems that need to be addressed. Plans to use urea inhibitors seem a sensible idea, as does extending IPCC emission permits to dairy farmers. Farmers should be paid for the delivery of public goods, and the new code on good practice for ammonia emissions, and better support for investment in farm infrastructure are both welcome. However, we note that other countries, such as Denmark and the Netherlands, have taken a more regulatory approach to controlling emissions which has led to significant reductions in their emissions.
80.We recommend that the Government considers whether it can better align policies on water, air and soil and the interaction between nitrogen in its various forms so that actions in one area do not have a negative impact in another. For instance, it needs to ensure that greater use of anaerobic digestion to reduce nutrients leaching into war sources does not lead to greater ammonia emissions, which have increased over the last two years. Better alignment needs to ensure that regulations and regulators are fully joined up across agriculture, water and air quality and that this is fully reflected in future agricultural payments based on the provision of ‘public goods’. For such a joined-up approach to work effectively after the UK leaves the EU, it is imperative that an independent overarching body can oversee these overlapping areas and enforce compliance. This further strengthens our case for an Environmental Enforcement and Audit Office (EEAO).
150 Q19 Professor Johnes; Wildlife and Countryside Link NO30032.
151 See Annex 2 for an overview of the pollutant impact of ammonia and nitrous oxides.
152 European Commission, EU AGRICULTURAL OUTLOOK FOR THE AGRICULTURAL MARKETS AND INCOME 2017–2030, (2017), p 70.
153 See: Environment, Food and Rural Affairs, Environmental Audit, Health and Social Care, and Transport Committees, Improving air quality, (HC 433; March 2018).
154 Nitrogen oxide compounds are formed when nitrogen and oxygen combine. NOx, which includes nitric oxide (NO) and nitrogen dioxide (NO2), is emitted from combustion processes. NO is subsequently oxidised to form NO2, although some NO2 is emitted directly. See: HM Government publication, Defra, Air Pollution in the UK 2016, September 2017, Glossary.
155 As above p 6–9.
156 See Royal College of Physicians and Royal College of Paediatrics and Child Health, Every breath we take: The lifelong impact of air pollution, (2016). A Report by the Government’s Committee on the Medical Effects of Air Pollutants in August 2018 put the figure at 36,000. See: A report by the Committee on the Medical Effects of Air Pollutants, Associations of long-term average concentrations of nitrogen dioxide with mortality, (August 2018).
157 See: Defra, Air Quality: Public Health Impacts and Local Actions, (accessed July 2018). The World Health Organisation (WHO) has put the cost as high as $83bn (£54bn) a year - see: WHO, ‘Economic cost of deaths from air pollution (outdoor and indoor) per country, as a percentage of GDP’, (April 2015). Public Health England published research in May 2018 that estimated between 2017 and 2015, health and social care alone costs arising from air pollution could be as much £5.56bn - see: Public Health England, Estimation of costs to the NHS and social care due to the health impacts of air pollution, (May 2018).
158 National Atmospheric Emissions Inventory, About Nitrous Oxide, (accessed 21 July 2018).
159 National Atmospheric Emissions Inventory, National Atmospheric Emissions Inventory, (accessed 21 July 2018).
160 George Eustice MP Q226.
161 Helen Wakeham (Environment Agency) Q230.
162 Jane Salter (Agricultural Industry Confederation) Q182–184
163 National Atmospheric Emissions Inventory, About Nitrous Oxide, (accessed 21 July 2018).
164 As above.
165 National Atmospheric Emissions Inventory, Nitrogen Oxides, (accessed 21 July 2018).
166 See Annex 4 of this Report for further details on the National Emission Ceilings Directive and Ambient Air Quality Directive and relevant transposing legislation.
167 These measures are implemented across the UK by delegated legislation: Air Quality Standards (Wales) Regulations 2010 (as amended); Air Quality Standards (Scotland) Regulations 2010 (as amended); and Air Quality Standards Regulations (Northern Ireland) 2010 (as amended). See Defra, UK and EU Air Quality Policy Context, (accessed 10 June 2018).
168 See: House of Commons Library, Brexit and Air Quality, (June 2018), p 15. The overall system is referred to as the local air quality management (LAQM) system. Guidance is issued by the UK Government and the devolved administrations to local government. Separate guidance is produced for London under the devolved powers of the London Mayor.
169 Committee on Climate Change, Reducing UK Emissions: 2018 Progress Report to Parliament, (June 2018), p 184 -188.
170 See for instance: Defra and the Environment Agency, Control and monitor emissions for your environmental permit, (Updated August 2018).
171 Defra, Emissions of Air Pollutants in the UK, 1970 to 2016, (February 2018).
172 National Atmospheric Emissions Inventory, Nitrous Oxide, (accessed 21 July 2018).
173 As above.
174 Committee on Climate Change, Reducing UK emissions 2018 Progress Report to Parliament, (June 2018), p 188.
175 As above, p 192.
176 NAO, Air Quality, (HC Paper 529; November 2017). For a list of the zones that did meet the limits - see House of Commons Library, Brexit and Air Quality, (June 2018), pp 17–18.
177 See: House of Commons Library, Brexit and Air Quality, (June 2018), pp 18–19.
178 European Environment Agency, Air quality in Europe—2017 report, Table 10.1, p 57.
179 In May 2018, it was reported that the UK had been referred to the European Court of Justice along with France, Germany, Hungary, Italy and Romania because of illegal air pollution levels. See: Damian Carrington, UK taken to Europe’s highest court over air pollution, Guardian, (17 May 2018) and BBC News, UK referred to Europe’s top court over air pollution, (17 May 2018); House of Commons Library, Brexit and Air Quality, (June 2018), pp 19–20.
180 See: House of Commons Library, Brexit and Air Quality, (June 2018), pp 21–26, for a review of the Judicial Reviews. The air quality plans included: Defra, Air quality in the UK: plan to reduce nitrogen dioxide emissions, (2015; withdrawn July 2017) and Defra, Air quality plan for nitrogen dioxide (NO2) in UK (2017; updated March 2018).
181 See BBC News, Government loses clean air court case, (21 February 2018); Sylvia Pfeifer, High Court rules UK air pollution plan is ‘unlawful’, Financial Times, (21 February 2018).
182 See above.
183 Commons Select Committees, Committees call for a new Clean Air Act, (15 March 2018). This included: requiring the automobile industry to contribute to a new clean air fund, following the ‘polluter pays’ principle; speeding up the phasing out of petrol and diesel cars; introducing a Clean Air Act to enshrine the right to clean air in UK law and a national health campaign to highlight the dangers of air pollution; widening help and support for local authorities breaching NO2 limit levels; aligning climate change schemes, urban planning, public transport and fiscal incentives with air quality goals; ensuring that costs of air pollution are part of plans for taxation and spending policies; ensuring that electric vehicle charging infrastructure prioritises air quality hotspots
184 Defra, Emissions of Air Pollutants in the UK, 1970 to 2016, (February 2018). See also: Defra, State of the Environment: Air Quality, (February 2018).
185 Environment Agency, Report on state of air quality in England highlights urgent action needed on ammonia emissions, (July 2018). Defra, State of the Environment: Air Quality, (February 2018), notes that of England’s nitrogen-sensitive habitats, 95% are adversely affected by nitrogen deposition (a 3% reduction since 1996) and that of England’s acid-sensitive habitats, 59% are affected by acidification (a 17% reduction since 1996). See also: See also: Defra, Biodiversity 2020: A strategy for England’s wildlife and ecosystem services Indicators, (July 2018), pp 145–147.
186 Fiona Harvey, Ammonia emissions rise in UK, as other air pollutant levels fall, Guardian, (February 2018). Environment Agency, Report on state of air quality in England highlights urgent action needed on ammonia emissions, (July 2018), p 11.
187 Defra, Code of Good Agricultural Practice (COGAP) for Reducing Ammonia Emissions, (July 2018), p 3.
188 Environment, Food and Rural Affairs Committee, Air Quality, (HC 479; April 2016).
189 As above, p 3.
190 In Denmark legislation was introduced regarding livestock installations, manure storage and spreading in 2001. In 2007, a new Danish Act on Environmental Permits for Livestock Installations was introduced, including buffer zones round specific habitat types with new and amended ammonia thresholds. The latter thresholds for permits were updated in 2012. In Netherlands, legislation includes the Ammonia and Livestock Act (2002) and the Decree on Low Emission Stables (2013/2015) alongside other emission reduction measures, which from 1 April 2018 imposes a reduction on the amount of cattle in the Netherlands. See: Helle Tegner Anker et al., Comparison of ammonia regulation in Germany, the Netherlands and Denmark – legal framework, Department of Food and Resource Economics (University of Copenhagen), (November 2017), p 11.
191 As above, p 22.
192 Defra, A Green Future: Our 25 Year Plan to Improve the Environment, (January 2018), p 13 and p 24.
193 Defra, Clean Air Strategy 2018, (May 2018).
194 As above, p 4.
195 As above.
196 As above, p 5 and p 7.
197 As above, p 6.
198 Defra, Code of Good Agricultural Practice (COGAP) for Reducing Ammonia Emissions, (July 2018).
199 Defra, Clean Air Strategy 2018, (May 2018), p 62–65.
200 Urease inhibitors are potentially useful tools for controlling or reducing gaseous losses of ammonia following fertilization with urea. They can restrict urea hydrolysis for up to 7 to 14 days, after which rain, irrigation, or soil mixing would be required to further restrict ammonia losses. See M R Martins et al, ‘Strategies for the use of urease and nitrification inhibitors with urea: Impact on N2O and NHa emissions, fertiliser-15N recovery and maize yield in a tropical soil, Agriculture, Ecosystems and Environment’, vol. 247, (September 2017), pp 54–62.
201 Defra, Clean Air Strategy 2018, (May 2018), p 60.
202 The Scheme, is also part of the Catchment Sensitive Farming partnership between Defra, the Environment Agency and Natural England, and will help farmers deliver the new Code of Good Agricultural Practice (COGAP) for Reducing Ammonia Emissions (see Chapter 4). The Scheme will fund a team of specialists who will work with farmers and landowners to implement the measures and include training events, tailored advice, individual farm visits and support with grant applications, all funded by the programme. See: Defra, £3m support scheme launched to reduce air pollution from farming, (September 2018).
203 Jane Salter (AIC) Q184; Country Land and Business Association NO3002.
204 Yorkshire Water Services Ltd NO30021; Wessex Water NO30007; UFU NO30009; AIC NO30040.
205 Jane Salter (Agricultural Industry Confederation) Q180 and Fraser McAuley (CLA) Q180.
206 NFU NO30012.
207 Green alliance NO30002; National Trust NO30046; Countryside Landowners Association NO30002; Wessex Water NO30007; NFU NO30012.
208 Helen Browning (Soil Association); Q181; Paul Cottington (NFU) Q181; Fraser McAuley (CLA) Q180.
209 Paul Cottington (NFU) Q181.
210 Yorkshire Water Services Ltd NO30021; Wessex Water NO30007; Northumbrian Water NO30044; Assured Biosolids Ltd NO30041.
211 Lagan Rivers Trust NO30017; Friends of the Earth Northern Ireland NO30033.
Published: 22 November 2018