Cleaner Air for Scotland 2: environmental report

Appendix A. Environmental Baseline

Air quality

The air that we breathe is fundamental to human life and the quality of our environment. The quality of life lived is placed at both short and longer term risk by poor air quality. In Scotland today, whilst industrial, domestic, agricultural, natural and transboundary pollution are all important air pollution sources, emissions from transport in urban areas remain the single biggest issue of concern.

Types of pollutants and sources include:

• Particulates PM₁₀ and PM2.5 - There are a number of AQMAs across Scotland designated due to an exceedance of the Scottish annual mean objective for PM₁₀. Main sources include combustion coal, solid fuel and diesel and road transport.
• Oxides of nitrogen - All high temperature combustion processes in air produce nitrogen oxides primarily from transport emissions but also energy generation, manufacturing and heating.
• Ground level ozone - A secondary pollutant arising as a result of chemical reactions between various air pollutants, primarily oxides of nitrogen and volatile organic compounds (VOCs), initiated by strong sunlight.
• Ammonia - a result of agricultural activities such as decomposition and volatilisation of animal wastes, including livestock manure / slurry management and spreading.
• Sulphur dioxide - Primarily from combustion of fuels containing sulphur, such as coal and heavy fuel oils used in energy generation.
• Volatile organic compounds – Primarily a result of road transport, the manufacturing industry and domestic combustion, solvent manufacturing and use, petrol distribution and handling energy generation, refineries and industry.

Figure 2. Main pollutant emissions in Scotland - 1990 - 2017

Source: Scotland’s Environment Web

Emissions of the eight main air pollutants are lower in 2017 than they were in 1990. This rate of decline is relatively similar for particulate matter (PM₁₀ and 2.5), oxides of nitrogen (NOx), non-methane volatile organic compounds (NMVOC), sulphur dioxide (SO₂) and carbon monoxide (CO). Lead (Pb) shows a much higher rate of reduction from 1990 to 2000 coinciding with the phase-out of leaded petrol from 2000, while ammonia (NH₃) emissions have declined at a slower rate than other pollutants^[25].

In regard to the domestic environment, since 2005 there has been an increase in emissions from the domestic sector due to an increase in popularity of open fires and wood burning stoves^[26]. Approximately 38% of UK primary particulate matter emissions come from burning wood and coal in domestic open fires and solid fuel stoves. This compares with industrial combustion (16%) and road transport (12%)^[27].

Trade sources suggest that c. 80 Ktonnes of coal is burned in Scottish homes. This is a significant contributor to PM2.5 due to the high particulate output of coal compared to approved smokeless fuels. Non-approved fuels also account for significant SO₂ emissions and such fuels range up to c.7% in sulphur content.^[28]

The National Atmospheric Emissions Inventory data (NAEI) for Scotland shows a continuous reduction in PM2.5 over recent years to below WHO recommended limits. In Scotland, research commissioned by DEFRA^[29]showed that emissions from wood burning in UK cities, including Glasgow, Edinburgh and Dundee were going down between 2009 and 2015. This was against a background of increasing stove sales. The main reason given for the drop in emissions is the replacement of open fires and older stoves with more modern appliances that produce lower amounts of particulate matter (PM₁₀ and PM2.5).

Ammonia is also recognised as a key air pollutant that can have effects on both human health and the environment. For example, ammonia deposition can lead to the acidification of soil and water which can degrade the natural environment. Ammonia deposition can also result in excessive nitrogen being supplied to sensitive habitats which can reduce biodiversity.

Emissions of some key pollutants in Scotland are EU compliant and some are already below World Health Organisation (WHO) guideline values, but there are both some general and some localised and periodic poor air quality areas which require urgent attention and action^[30]. Where air standards are not being met, local authorities in Scotland have set up Air Quality Management Areas (AQMAs) to help reduce pollution. There are currently 38 AQMAs across Scotland’s 32 Local Authorities and these have been established primarily as a result of road traffic emissions. Compared to 1990, in 2017 there were reductions in emissions across all air pollutants, including ammonia (15%), PM₁₀ (63%), PM_2.5 (68%), NMVOC (65%), nitrogen oxides (71%), carbon monoxide (84%) and sulphur dioxide (96%). ^[31]

Finally, studies are emerging which explore the effect of the COVID-19 pandemic currently being experienced. Time variance analysis of air quality in Scotland during COVID-19 lockdown shows that NO₂ and particulate matter emissions experienced significant drops. Figures for the period March - May 2020 show a decrease of between 51% and 81% in relation to NO₂ emissions compared to previous years. Particulate matters emissions have also seen a significant reduction with PM_2.5 down between 0% and 56%, and PM₁₀ by between 9% and 53% compared to previous years. These changes have been likely associated with the drop in road traffic within Scotland’s cities. ^[32]

Key Pressures

• Key pressures on air quality include emissions from transport, industrial, domestic, agricultural, natural and transboundary sources.
• In urban areas, transport emissions are the biggest source of air pollution.
• Emissions of the majority of air pollutants have declined in recent years, with ammonia declining at a slower rate than other pollutants.
• Ammonia is recognised as a key air pollutant that can have significant effects on both human health and a detrimental impact on soils, water and biodiversity.
• Poor air quality continues to affect human health and the environment in some areas.

Population and human health

Scotland has a population of around 5.4 million people with a population density among the lowest in Europe despite significant variation between highly urbanised areas in the Central Belt and rural and island areas. Scotland’s population is expected to rise to approximately 5.7 million by 2041. Life expectancy has also generally increased across Scotland since 1981 with life expectancy of 75.3 years for males and 77.1 years for females. However, life expectancy in Scotland remains lower than the UK average and is the lowest of all UK constituent countries for both males and females.^[33]

The Scottish Index of Multiple Deprivation (SIMD), which identifies small concentrations of multiple deprivation across all of Scotland, shows that the 15% most deprived data zones in Scotland are located predominantly in urban areas, including Glasgow, Dundee, and Edinburgh.^[34]

Outdoor air pollution is widely accepted as causing damage to human health, from pre-birth to old age and air pollution globally is recognised as the most serious of all environmental health problems^[35]. Particulate matter (PM), NO₂, SO₂ and O₃ are the most harmful pollutants to human health with studies showing that prolonged exposure to lower levels of these pollutants can have a more detrimental impact on health than exposure to high peak pollution events. Poor air quality is associated with both short and long-term adverse effects on human health, including irritation of the respiratory system and the exacerbation of existing health conditions, particularly heart disease and respiratory illnesses in vulnerable individuals.^[36]

In 2016, the level of PM_2.5 was associated with an estimated equivalent number of attributable deaths across Scotland of 1,724. This is a decrease compared to the estimation of 2,070 in 2010 and is associated with the reduction of PM_2.5 concentrations from 6.8 µg/m³ to 5.2 µg/m³ between 2010 and 2016. In addition, highly urbanised areas, such as Dundee, Edinburgh, Glasgow and Aberdeen were found to have higher concentrations of particulate matter in comparison with rural locations such as the Western Isles.^[37]

In terms of indoor air pollution, the World Health Organisation (WHO) estimated that in 2017 up to 117,000 (early) deaths each year in Europe could be attributable to indoor air pollution; including up to 3% of all heart disease, 3% of chronic pulmonary disease, 3% of stroke and 2% of lung cancer fatalities^[38].

Sources of indoor air pollutants differ by setting (e.g. home, school, workplace). Key sources include combustion particles and gases (CO, CO2, NOx) from burning fuels for heating and cooking and from tobacco smoke; chemicals used for cleaning and disinfection; perfumed products; chemicals, including volatile organic compounds (VOCs) released from building materials, furniture, fixtures and fittings such as carpets and wall coverings^[39].

The degree of correlation between indoor and outdoor air quality depends on physical factors such as the rate of air exchange. However, buildings are increasingly being designed to reduce active heating needs and associated carbon emissions, by making them more air tight which has the potential to lead to pollution remaining in the occupied space^[40].

Air pollution and the consequent impacts on human health are not evenly spread and exposure can fall disproportionately on disadvantaged or vulnerable populations; typically, people living in more deprived areas, those with pre-existing health problems, the very young and the old. Air pollution in Scotland is often worse in inner city deprived areas, worsening existing inequalities in local environmental quality and human health.^[41]

Climate change also has the potential to impact on air quality and associated human health, for example through exacerbating poor air quality and associated health problems.

Key Pressures

• Key pressures on population and human health include outdoor air pollution which is known to causes damage to human health across a wide range of conditions.
• Highly urbanised areas are likely to have higher concentrations of pollution than rural locations.
• Early deaths and other health impacts can be associated with indoor air pollution with sources differing by setting but including emissions from burning fuels for heating and cooking.
• Air pollution and the consequent impacts on human health are not evenly spread and disproportionately linked to more vulnerable groups and deprived areas.
• Climate change has the potential to exacerbate poor air quality and associated health problems.

Climatic factors

Air quality and climate change are intrinsically linked as they both arise from broadly the same sources. For example, road transport makes up 68% of transport greenhouse gas emissions and is also a source of a number of air pollutants such as particulate matter and nitrous oxides.^[42]

The global climate is changing. Since the 1880s, human activity has led to a significant increase in atmospheric greenhouse gas emissions and global warming. This has resulted in an increase in the average temperature of the atmosphere and oceans; a reduction in snow and ice cover; and sea level rise. At the UK level, there was a 4% increase in rainfall for in the period 2008 – 2017 compared to 1850 – 1900, as well as a 1°C increase in temperature and a 16 cm rise in sea level. In Scotland, the period 2008 – 2017 was an average of 0.7°C warmer than 1961 – 1990 and had fewer days of air and ground frost. An increase in precipitation (11%) has been observed for the same period. The amount of rain from extremely wet days across the UK has also increased by 17% with the biggest observed changes seen in Scotland.^[43]

Key pressures on climate change include greenhouse gas emissions from a range of sectors with the highest contributors being the transport sector (excluding international aviation and shipping) (12.9 MtCO₂e), agriculture and related land uses (7.5 MtCO₂e), business (8.4 MtCO₂e), energy supply (6.8 MtCO₂e), and the residential sector (16.2 MtCO₂e). Relatively minor contributions were reported for public sector buildings, industrial processes, and waste management. Land use, land use change and forestry was a net carbon sink and contributed to reducing emissions by approximately 5.4 MtCO₂e in 2018. ^[44] In general, climate change projections suggest observed climate trends will continue to intensify in the future, including:

• an increase in both summer and winter average temperatures across both low and high emission scenarios;
• drier summers and wetter winters;
• increase in sea level and coastal erosion;
• an increase in the intensity of rainfall; and
• increased risk of flooding, drought, and extreme weather events.^[45], ^[46]

While warmer summers could lead to increases in productivity in some cases (e.g. forestry) due to the fact nitrogen and water are not limiting factors, a warmer climate can negatively impact wider ecosystem services – e.g. increase the spread of pathogens and impacts on biodiversity. Climate change can also have an impact on air pollution patterns and exacerbate negative effects on population and human health in relation to air quality.^[47] Population and human health vulnerabilities to climate change, such as ones due to higher temperatures and an increase in extreme weather events, can further compound the negative effects on human health as a result of air pollutants (e.g. respiratory conditions). ^[48] European studies on heatwave episodes have consistently shown a synergistic effect of air pollution and high temperatures and their impact on human health. In addition to this, allergen patterns are changing as a result of climate change and air pollution can modify pollens’ allergenic potential, particularly in the presence of specific weather conditions. This can all have consequences for population and human health and more specifically allergic respiratory conditions.^[49]

Finally, climate change could affect air quality at different scales through changes in chemical reaction rates, boundary layer heights affecting vertical mixing of pollutants, as well as changes to airflow patterns.^[50]

Key Pressures

• Air quality and climate change are intrinsically linked as they both arise from broadly the same sources.
• Key pressures on climate change include greenhouse gas emissions from a range of sectors including transport (37%), agriculture and related land uses (24%), business/Industry (22%), energy (15%), and residential (15%).
• Climate change has the potential to exacerbate key pressures on a range of environmental receptors
• Climate change could alter current patterns and concentrations of air pollution.
• Key inter-related climate change risks include:
  • flooding and coastal change risks to communities, businesses and infrastructure
  • high temperature-related risks to health, well-being and productivity
  • shortages in the public water supply, agriculture, energy generation and industry
  • risk to natural capital, including terrestrial coastal, marine and freshwater ecosystems, soils and biodiversity
  • domestic and international food production and trade
  • new and emerging pests and diseases, and invasive non-native species, affecting people, plants and animals.

Soil

Air and soil quality are linked through common sources of pollution. Scotland has a diverse range of soils, generally more organic, more acidic, more leached and wetter than those of most other European countries. Over 25% of Scotland is used for arable crops (mostly in the eastern half of the country) and improved grassland, mostly on the more mineral soils of the central belt and in lowland areas and predominantly found in the south west. The remainder of the country is occupied by semi natural habitats over more organic soils with over 20% of Scotland being cover in peatland habitat on peat soils. ^[51]

Soil is a non-renewable resource which supports a wide range of functions and provides many environmental, economic and societal benefits including^[52]:

• Providing the basis for food and biomass production;
• Storing carbon and maintaining the balance of gases in the air as a major store of terrestrial carbon;
• Providing raw materials such as the use of sand and sand gravel in construction and use of peat as a fuel;
• Providing valued habitats and sustaining and supporting biodiversity;
• Controlling and regulating environmental interactions such as water flow and quality;
• Preserving cultural and archaeological heritage by providing records and protective cover;
• Providing a platform for buildings and roads but therein largely losing its capacity to carry out other functions.

Soil quality is defined as the ability of soil to carry out these functions^[53]. The concept of ecosystems services has similarities to soil function but with a stronger human dimension by identifying the benefits that soils provide to society. Soils contribute to all four types of ecosystem services such as food provision, fibre and raw material (a provisioning service), provision of clean water (a regulating service), protects and is part of Scotland’s cultural heritage (a cultural service) and soil formation itself (a supporting service).^[54]

Key pressures on soil include changes in land use and management and soil pollution and contamination. Changes in land use and management can result in change in soil organic matter which impacts on soil health and its ability to hold carbon, water, nutrient and contaminants, and sustain biodiversity. Soil Organic matter underpins most of the fundamental soil properties and soil functions. Loss of soil and degradation of the soil surface conditions of existing soils or soil reinstated following planning activities directly impact on soil health. Soil pollution and contamination can be locally significant and threats to soil can be exacerbated by misuse of chemicals; waste management and recycling operations during development^[55].

Generally, the addition of nitrogen has a positive effect on soil quality of agricultural soils, because it enhances soil fertility and conditions for crop growth. However, it generally has a negative effect on soil quality of natural soils, because it results in changes in plant diversity. Soil acts as a filter and buffer for nitrogen, protecting water and atmosphere against nitrogen pollution. However, the filter and buffer capacity of

soils is frequently exceeded by excess of nitrogen use in both agricultural and natural soils, which results in emission of nitrogen to the wider environment.^[56]

Key pressures on soil can be compounded by the effects of climate change which can contribute to both erosion and compaction. For example, the risk of water-based soil erosion is expected to increase as a result of projected increases in the frequency and intensity of heavy rainfall events resulting from climate change.

Key Pressures

• Air and soil quality are linked through common sources of pollution.
• Changes in land use and management can result in change in soil organic matter which impacts on soils ability to perform its range of functions.
• Soil pollution and contamination can be locally significant and threats to soil can be exacerbated by mis-use of chemicals; waste management and recycling operations during development.
• Ammonia deposition linked to modern agricultural practice can lead to the acidification of soil negatively impacting biodiversity.
• Key pressures on soil can also be compounded by the effects of climate change which can contribute to both erosion and compaction.

Water

Scotland’s water environment is a valuable resource, providing a range of benefits such as the provision of water for drinking, industry (e.g. fisheries and hydropower development) and recreation. Scotland’s waters also support a diverse range of habitats, containing a number of nationally and internationally important species. Scotland has approximately 125,000 km of rivers, 25,500 lochs over an area of 2,000 km2, 49 estuaries covering 1,000 km2, 19,000 km of coastline accounting for 48,000 km2, and 462,000 km2 of offshore water found across Scotland and its marine territory. While covering only approximately 2% of Scotland’s land area, rivers and lochs contain 90% of the UK’s surface freshwater.^[57]

Significant reductions in pollution have been realised over the last 25 years. Overall, in 2018 65.7% of Scotland’s groundwater and surface water bodies were at good or better status, a slight increase since 2017^[58]. Almost two thirds of lochs surveyed are also in good or high condition and nearly 80% of ground water bodies in Scotland are in good condition.^[59]

Key pressures currently affecting the condition of rivers and lochs in Scotland are man-made barriers to fish migration, physical changes to beds and banks and rural diffuse pollution. Groundwater quality is affected by diffuse pollution from rural sources and discharges from industry such as mining and quarrying whereas groundwater flows and levels are affected by agricultural irrigation and industry. ^[60]

Diffuse pollution which can result from atmospheric deposition due to activities such as fertiliser use, can have an effect on both air and water quality. Heightened nitrogen concentrations can cause the acidification and eutrophication of water bodies. Eutrophication occurs when the concentrations of otherwise limiting nutrients increase, allowing aquatic plants and algae to grow unchecked and depleting oxygen levels. ^[61]

Key Pressures

• Key pressures on water in some areas include changes to water flows and levels resulting from land use change, invasive species, poor water quality and overall ecological condition.
• Atmospheric deposition associated with activities such as fertiliser use can have an effect on both air and water quality.
• Key pressures on freshwater include physical changes to beds and banks and rural diffuse pollution.
• Similarly to soil, ammonia deposition can lead to the acidification of water, negatively impacting biodiversity, flora and fauna.
• Groundwater quality can be affected by diffuse rural pollution, whereas groundwater flow and levels can be affected by agricultural irrigation and industry.

Biodiversity, flora and fauna

Scotland’s landscape and habitats are diverse in nature and range from uplands, wetlands, grasslands, forests and woodlands, to the Scottish coast and marine environment, as well as terrestrial water bodies and river systems. These ecologically complex landscapes and habitats are home to approximately 90,000 flora, fauna and microbial species.

Designated protected areas include 1,423 Sites of Special Scientific Interest (SSSI)^[62], 51 Ramsar Sites^[63], 153 Special Protection Areas (SPAs)^[64], and 244 Special Areas of Conservation (SAC)^[65]. The UK Biodiversity Action Plan also identified 39 priority habitats and 197 priority species that either occur or are known to have occurred in Scotland in recent times, which later helped to inform the scope and focus of Scotland’s Biodiversity Strategy. In addition, many undesignated areas such as urban parks and gardens contain a variety of habitats and ecosystems that are important biodiversity assets^[66].

Key pressures on biodiversity include pollution, the spread of invasive species and wildlife disease, land use intensification and modification, pollution and climate change.

Damage caused by air pollution to biodiversity may be less obvious and more difficult to quantify but poor air quality can cause damage to plants and animals, impact on biodiversity through its contribution to eutrophication, acidification and otherwise damaging sensitive habitats. This can result in species loss, habitat composition changes and increased sensitivity of organisms to environmental stresses.

Pollution from industry, agriculture and transport impacts on air quality and sensitive habitats across Scotland. In March 2019, 78.9% of protected nature sites were in favourable overall condition^[67]. The most recent report on trends in critical load and critical level exceedances in the UK shows improving trends for many pollutants, with the exception of ammonia. A notable proportion of habitats are at still risk, for example excess nitrogen deposition is reported on 40.8% of sensitive habitats, and more than 60% of designated sites in Scotland experience exceedance of nutrient nitrogen for one or more features. At a UK level, Scotland has shown the greatest improvements in the area of N-sensitive habitats with critical load exceedance falling by almost one-third from 59.4% in 1995-97 to 40.8% in 2014-16. ^[68]

The impact of nitrogen emissions on sensitive habitats in particular is well-documented, and is a significant threat to biodiversity in Scotland. Nitrogen emissions from combustion plants, intensive agriculture and transport causes acidification, eutrophication and direct tissue damage to plants. Most natural plant communities are adapted to low nitrogen levels and an excess causes shifts in species composition towards a less diverse assemblage of plants and the direct loss of sensitive species, such as lichens and bryophytes for which Scotland has international renown. Recent research commissioned by Scottish Natural Heritage^[69] which looked at changes in floristic composition from repeat surveys, has shown nitrogen deposition to be a key driver of change across a wide range of habitats in Scotland. The Scottish uplands are particularly sensitive due to rainfall depositing nitrogen from a variety of sources over a wide area.

In the period 2015 – 2017, the percentage of SACs with critical load in relation to nutrient nitrogen exceedance decreased between 1996 and 2016 was 36.3%, while the ones for SPAs and SSSIs was 48.8% and 49.6% respectively. Scotland has seen the largest reduction in the area of acid-sensitive habitats with exceedance of acidity critical loads – this has fallen by two thirds from 68.2% (32,774 km2) in 1996 to 22.7% (10,933 km2) in 2016. Similar trends were observed in relation to habitats at risk from eutrophication. At the same time, less than 0.5% of sites that have a conservation designation in Scotland currently receive ammonia concentrations above the critical level of 3 µg m-3 anywhere across a site – this is lower than elsewhere in the UK. While these figures have declined since 1995 and compare favourably with other parts of the UK, they represent a significant proportion of Scotland’s natural environment and wildlife habitat.^[70]

Some of the spread of invasive species and wildlife disease can be attributable to a growing global trade of plants and animals. Land use intensification, modification and overgrazing can lead to a reduction of diversity, quality and connectivity of landscapes and habitats.

Climate change is causing a shift in weather patterns which are affecting nature across the country through influencing natural processes that maintain our habitats, ecosystems and landscapes^[71].

Key Pressures

• Air pollution can cause damage to plants and animals and other impacts on biodiversity that can result in species loss, habitat composition changes and increased sensitivity of organisms to environmental stresses.
• Ammonia is a key pollutant and nitrogen deposition is a key pressure on a wide range of habitats and nitrogen emissions from combustion plants, intensive agriculture and transport causes acidification, eutrophication and direct tissue damage to plants.
• Key pressures on biodiversity include land use intensification and modification, pollution and climate change.
• Climate change including shifting weather patterns can affect nature across the country.

Material assets

Agriculture and land use

Agriculture is the dominant land use in Scotland, with 75% of Scotland’s land mass under agricultural production. A diverse range of farming takes place across the country including arable farming, crofting, hill farming and lowland livestock and dairy farming^[72]. Over half of Scotland’s agricultural land is used for upland sheep farming and mixed sheep and beef cattle farming^[73]. In 2018, farms covered 5,603,815 ha of land in Scotland with grazing land an additional 579,847 ha. Sheep and cattle farming was the biggest farming type in 2018, followed by forage farming (for animal feed), mixed and general cropping.^[74]

Agricultural land use has a strong influence on the landscape and environment, sustaining important habitats for biodiversity including unimproved grassland, cultivated fields, walls and hedges, watercourses, wetlands, moorland and upland grassland. Changes in land use can have an impact on wildlife habitats and water pollution (e.g. via diffuse pollution).

Agricultural emissions related to air quality are dominated by ammonia (NH₃). Ammonia is a reactive nitrogen compound which is released when slurries, manures and nitrogen fertilisers come into contact with the air. It produces odours and is mobile, combining with acids and particulates, resulting in polluting and nuisance effects which impact on both human and ecosystem health. Ammonia can be lost whenever slurry or manure is exposed in this way.

Agricultural practices can impact on air quality and since 1990, decreasing animal numbers and a decline in fertiliser use has seen a reduction in emissions. More recently however, an increase in the use of urea-based fertilisers has led to higher emissions. Cattle manure management accounted for 38% of agricultural emissions in 2017 (non-dairy: 28%; dairy 10%), followed by cattle manure applied to soils (19%) and inorganic fertiliser application (16% total; 9% to tillage, 7% to grassland)^[75].

Agriculture also produces appreciable amounts of particulates (PM₁₀: 14.4% and PM_2.5 7.2% of totals) and volatile organic compounds (VOCs) (12.2% of total). Sources of PM₁₀ include farm operations (31%) and manure management (cattle (25%), sheep (20%), laying hens (9%), other poultry and broiler chickens (6% each). Most emission sources have decreased since 1990, however those associated with laying hens has increased, especially since 2008^[76].

PM_2.5 emissions arise from manure management (cattle (57%), sheep (22%)) and farm operations (14%). Manure management associated with laying hens, other poultry and broiler chickens contribute 2% each. Emissions of PM_2.5 from all sources have declined or remain unchanged since 1990, with little further change since 2010. Most emission sources of VOCs have decreased since 1990, except for poultry. VOC emissions are dominated by cattle manure management (66%), followed by cultivated crops (14%).^[77]

Intensive land management is one of the main challenges to farmland wildlife and a shift toward intensification has resulted in a change in biodiversity which could have major implications for food production. Increased field sizes and use of agricultural chemicals has led to a potentially serious decline in pollinators such as bees, which in turn, can negatively affect crop volumes^[78]. Poor land management can also lead to increased soil erosion, which can lead to loss of top soil and reduce soil function^[79].

The demand for the services that the natural environment provides, such as food, is likely to grow in line with population growth.

Domestic/Built environment

In 2017, 20% of total Scottish energy consumption came from renewable sources; the highest level to date and an increase from 16% in 2016. This is driven by record years for both renewable electricity and heat generation due to an increase in installed capacity for renewable electricity and heat on 2016 - by 1.1 GW and 0.3 GW for electricity and heat respectively. Heat generation in Scotland in 2017 comprised of 79% mains gas, 12% electricity, 6% oil, 3% other fuels (e.g. solid fuel), and 1% communal/ district heating.^[80]

Key pressures on the domestic/built environment include emission levels associated with domestic burning. Despite actual levels being somewhat uncertain it is considered that emissions attributable to domestic burning contribute to air pollution, the main pollutants of concern being PM₁₀, PM_2.5, nitrogen dioxide and sulphur dioxide.

Key Pressures

• Emissions associated with agricultural practices, mostly dominated by ammonia release when slurries, manures and nitrogen fertilisers come into contact with air , leading to diffuse pollution in water and soil.
• Intensive land use/ land management practices putting pressure on associated natural resources such as land (and environmental receptors such as soil, water and biodiversity).