Cleaner Air for Scotland 2: consultation

Consultation on a draft new air quality strategy for Scotland, taking into account the recommendations arising from the independent review of the Cleaner Air for Scotland strategy.

6. Industrial Emissions Regulation

88. Emissions from industrial activities in Scotland have been subject to increasingly strict regulation since the mid 1990s as a result of Scottish, UK and EU legislation and policy implementation.  SEPA has been recording the mass emissions from the largest regulated sites since 2002 using its Scottish Pollutant Release Inventory (SPRI) which collates data for a wide range of pollutants[56].  Emissions from industry can be variable as controls are typically set based on emission limit values (ELVs) from point sources (rather than mass emissions from the installation as a whole).  As a result, emissions can fluctuate over time due to production needs, but still be in full compliance with permit conditions. A summary of the emission trends from SEPA regulated sites since 2002 is included in the CAFS review emissions working group report[57].

89. The provisions of this regulatory framework are wide ranging, comprehensive and provide a good level of protection for the environment as a whole, using the principles of best available techniques (BAT).  Therefore any scope for requiring further reductions of air pollutant emissions on a compulsory basis must be considered very carefully.  Any environmental benefits must be balanced against costs of regulation (for both industry and SEPA) and a robust justification provided for additional controls.  Nevertheless, SEPA is currently working with 15 sectors which partially or fully cover industrial emission sources to encourage them to move beyond compliance on a voluntary basis.

Sector plan approach

90. SEPA can work with regulated business through sector plans to help drive improvement across environmental media as well as influencing circular economy choices. Air pollution is considered a cross cutting issue in sector plans. By their nature, sector plans deal with issues which can contribute to emissions to air. For example, all sectors will use transport for materials, goods and people. This is likely to be the single largest source of uncontrolled emissions from any sector, on its own or in combination, for both air pollution and greenhouse gas emissions. 

91. Sector-specific emissions of air pollution (such as point source releases, materials handling and fugitive emissions) are likely to be controlled through SEPA’s existing regulatory tools such as permitting, inspection and enforcement (e.g. via PPC and WML). A core concept of industrial regulation in SEPA is continual improvement and in most cases, mandatory environmental performance standards will drive any dynamic improvement on a cyclical basis. The sector plans will act as an additional focus, by providing enhanced clarity on pre-existing mandatory standards.

Beyond compliance

92. SEPA believe that those societies and economies that are low resource use, low energy use, low water use and low waste will be the most successful in the 21st century. Beyond compliance is about businesses choosing to go further than the environmental obligations that are placed upon them. These progressive businesses will view environmental excellence as an opportunity, not a problem. This can include looking at suppliers, auditing processes and evaluating buildings, fittings and equipment. SEPA will work with partners to support businesses that choose to implement these types of beyond compliance opportunities and achieve environmental, economic and social benefits. Many actions to reduce impacts on climate change, such as reducing fuel use or switching to alternative fuel sources, are often likely to be cost effective, and have co-benefits for outcomes such as air quality. 

Non-exhaust emissions and Non-Road Mobile Machinery

93. Non-exhaust emissions (NEE) from road traffic are particles that arise from the wear of brakes, tyres and the road surface and from the resuspension of road dust[58]NEE are significant contributors to particulate emissions from road transport, with particles from brake wear, tyre wear and road surface wear constituting 60% of primary PM2.5 and 73% of primary PM10 (by mass) from road transport[59 60]

94. Strategies to mitigate NEE from road traffic can be split broadly into traffic management, behaviours and legislation/standards. A number of opportunities exist for the Scottish Government to contribute into the emerging science of road traffic NEE during the life of CAFS 2. 

95. Non-Road Mobile Machinery[61] (NRMM) covers construction plant, transportation refrigeration units (TRU) or some agricultural machinery.  NRMM does not utilise the Euro emission standards as adopted by vehicles.  Rather, the UK Government introduced new legislation via the Non-Road Mobile Machinery (Type-Approval and Emission of Gaseous and Particulate Pollutants) Regulations 2018[62], where the most recent NRMM stage is Stage V[63].  However, not all NRMM machinery will comply with the Stage V level as they were manufactured before the 2018 Regulations were established. 

96. In relation to construction NRMM, the Scottish Government will publish construction NRMM guidance based on existing industry-led guidelines such as the Supply Chain Sustainability School via their Plant Charter[64] and the London NRMM guidelines.  Guidance would focus on construction projects in AQMAs, cover construction NRMM with a net power rating of between 37kW and 560kW and seek to progressively tighten over time using the NRMM engine emission ‘stages’.  

97. TRU systems in light and heavy commercial vehicles are powered by either an auxiliary diesel unit or a direct belt drive linked to the vehicle engine. The NOX and PM emissions per kilometre travelled for TRUs are substantially poorer when compared to the Euro VI emissions from diesel vehicles exhausts[65].  One key challenge is that auxTRU diesel units can often be below the 19kW cut-off limit for compression-ignition engines in NRMM regulations[66] which means that they do not need to comply with any emissions standard. 

98. There is no single legal, operational, behavioural or technological solution to reduce TRU emissions.  Therefore, the Scottish Government will develop an emissions impact and evidence base on TRU emissions with research into emissions testing of TRUs to develop an applicable emissions factor, along with encouraging the use of direct drive electrically powered TRUs and collaborating with the UK Government to implement stricter emission standards on TRUs and encourage the creation of TRU legal standards for new and existing vehicles. 

99. Areas for possible further consideration include:

  • The environmental benefit in bringing currently unregulated sectors (which have not been prescribed by EU legislation) such as non-waste anaerobic digestion into existing legal frameworks; and
  • reviewing the current legal framework to investigate whether all appropriate industrial sectors are subject to regulation, to identify and remove legal gaps and ambiguities from legislation and investigate the use of general binding rules (GBRs) for ensuring compliance with codes of practice.

100. Even without taking these additional points into account, implementing EU requirements into domestic legislation has demonstrated that controls placed on industry are proportionate and effective in reducing emissions.  Therefore, provided current EU requirements are maintained in Scotland following the UK’s exit from the EU, further emissions reductions should be achievable, with additional benefits for air quality.


We will:

  • Ensure that EU standards and principles relating to emissions of air pollutants continue to apply in Scotland following the UK’s exit from the EU.
  • Utilise SEPA’s sector plan approach to encourage businesses to go beyond compliance to achieve further reduction in air pollutants and greenhouse gas emissions.  
  • As part of the review of the Clean Air Act (see domestic burning actions), address the regulatory gap relating to stack height assessment for SEPA permitted sites.
  • Explore opportunities across traffic management, behaviours and legislation/standards to reduce NEE from road traffic.
  • Contribute into research to develop a consistent method of measuring NEE from road traffic, in order to improve the understanding of NEE emissions in Scotland. 
  • Engage with industry to produce guidance on requirements for gaseous and particulate emissions from NRMM in the construction sector.
  • Develop an emission impact and evidence base on TRU emissions.

Questions on industrial emissions regulation 

The below questions relate to the industrial emissions regulation chapter of the CAFS 2 strategy. There is an opportunity to comment generally on the package of actions we intend to deliver, as well as two further questions relating to specific actions. Please note that domestic (household) combustion emissions and agricultural emissions are covered in Chapter 7 and transport emissions are covered in Chapter 8 of this consultation paper. 

9. Do you agree with the package of actions put forward in the Emissions Regulation chapter? 

A) Yes

B) No

C) Neither agree nor disagree

Additional comments to support your answer

10. Should currently unregulated sectors such as non-waste anaerobic digestion and non-road mobile machinery be brought into existing legal frameworks? 

A) Yes

B) No

C) Don’t know

Please explain your answer 



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