Comparison basis: The detailed comparison is between the supplied 2018 edition and the third EMAQ+ edition dated 20 May 2026. The 2026 document also records intermediate amendments made in 2022.
What has actually changed?
The May 2026 document is the third EMAQ+ edition. It builds on the 2018 guidance and the amendments recorded in 2022, but retains the familiar approach to assessing kitchen odour risk. The same scores are used for dispersion, receptor proximity, kitchen size and cooking type, and the thresholds for low, high and very high odour control remain unchanged.
The more important change is that the guidance no longer discusses a commercial kitchen extract principally as an odour and noise problem. It now gives much greater consideration to grease, smoke and PM2.5, including the way these emissions are generated, captured and treated.
This is a sensible and overdue development. It does not, however, amount to a complete method for assessing PM2.5 impacts from commercial kitchens.
PM2.5 is now part of the assessment
The most obvious change is the repeated reference to PM2.5 throughout the document. A new section explains how cooking generates grease aerosols, smoke, volatile organic compounds and fine particles. It describes how heated oils can vaporise and subsequently condense into fine droplets, while charring and high-temperature cooking can produce smoke particles smaller than 0.3 micrometres.
The previous descriptions of grease and smoke loading have therefore been revised to include PM2.5. A new appendix also compiles published particulate emission data for different foods, cooking oils and cooking methods.
This changes the question that should be asked when assessing a kitchen extract. It is no longer sufficient to consider only whether the discharge is likely to cause an odour at the nearest dwelling. There is now a separate question about the particulate matter being discharged and whether it should be controlled.
The guidance recognises that grease, smoke and PM2.5 control may still be required where a stack discharges above roof level, particularly in city centres or other locations where existing PM2.5 concentrations are high. A high-level discharge can provide effective dilution and dispersion, but it does not reduce the quantity of particulate matter released.
This is probably the most important conceptual change in the new document.
What the guidance does not provide
There is no separate PM2.5 assessment procedure. The guidance does not provide:
- An emission limit for a commercial kitchen extract.
- A background concentration above which particulate control is automatically required.
- A universal percentage removal requirement.
- A method for calculating the effect on ambient PM2.5 concentrations.
- A separate PM2.5 risk score.
The existing odour risk assessment should not therefore be used as a proxy for a PM2.5 assessment. The relative odour and particulate risks will not always be the same. Some cooking processes may have a greater particulate loading than their odour classification alone would suggest.
The guidance introduces PM2.5 into the decision but leaves consultants and local authorities to decide when further assessment or control is justified.
The design requirements have changed
There are several important changes to the opening performance requirements. The recommended maximum internal kitchen temperature has reduced from 28°C to 26°C, while the recommended maximum relative humidity has reduced from 70% to 65%. These are design criteria presented by EMAQ+, not statutory workplace exposure limits.
The former NR40 to NR50 internal noise criterion has been replaced in the summary by a general requirement to comply with HSE workplace guidance. The detailed text also states that the extraction system should ideally not contribute more than 70 dB at the operator position.
The recommended canopy face velocities have reduced from 0.25, 0.35 and 0.50 m/s to 0.15, 0.225 and 0.30 m/s for light, medium and heavy loading respectively.
This does not necessarily mean that smaller extract systems will be acceptable. The new values form part of the face velocity calculation method. The required extract rate still needs to reflect the canopy geometry, the appliances beneath it and the heat and pollutant loading.
A more standards-led approach
The new guidance is more closely aligned with the EN 16282 series. It recognises four calculation methods: thermal convection, face velocity, appliance power input and air changes. Thermal convection remains the preferred approach, but it is no longer described as the only reliable method.
The older rule-of-thumb methods based on meals served, kitchen floor area and linear filter length have been removed. This is an improvement. Extract rates should be based on the heat and pollutant load that needs to be captured rather than a general assumption about the number of meals being prepared.
Some of the simplified requirements in the front summary are less prescriptive, but the detailed sections continue to refer to EN 16282 and other industry guidance. For example, the previous requirement for access panels at 2 m centres has changed to intervals of less than 3 m in Section 4.6. It has not simply become an undefined requirement for panels at suitable intervals.
The previous supply and extract duct-velocity table has been replaced by a general range of 2.5 to 8 m/s, depending on the part of the system. Detailed ductwork, fire and mechanical design should therefore be demonstrated against the relevant standards rather than treated as having been fully specified by EMAQ+.
A statement that a system complies with EMAQ+ should not be accepted without the calculations and design information needed to demonstrate that compliance.
Better information on abatement equipment
The sections covering emission-control equipment have been expanded considerably.
The revised discussion of electrostatic precipitators presents ASHRAE test data showing removal efficiencies of approximately 90% to 98% for particles within the PM2.5 range. This should not be treated as a default efficiency for every commercial ESP. Performance depends on the unit, airflow, residence time, number of passes, pollutant loading and condition of the collection plates.
The inclusion of an ESP on a drawing does not demonstrate that effective particulate control will be achieved. The equipment needs to be correctly sized for the actual airflow and grease loading, and the maintenance arrangements need to be credible.
The guidance also confirms that an ESP should not be treated as the primary means of controlling gaseous odour. It can remove grease and smoke particles, including odorous material associated with those particles, but it is not by itself a complete odour-control system.
Wet scrubbing has been reinstated after being largely dismissed in the previous edition. The guidance now discusses venturi scrubbers, packed towers and water-wash systems, together with their space, noise and maintenance requirements.
The treatment of UV-C and ozone systems is also more useful. It distinguishes photolytic oxidation from electrical ozone generation and discusses contact time, temperature, moisture, lamp selection, cleaning, residual ozone and the possible need for a downstream catalyst or activated carbon.
The guidance indicates that oxidation using ozone alone may require a reaction time of up to 20 seconds, while combined UV-C and ozone treatment may require a much shorter reaction time. This matters because many systems do not have enough downstream ductwork to provide the required contact time.
Simply specifying ESP and UV is not a complete design. The proposed equipment needs to be supported by airflow calculations, relevant performance data and a suitable maintenance arrangement. Some of the evidence cited in the revised guidance comes from manufacturers or technology providers, so product-specific claims should still be supported by independent test data where this is available.
The odour risk assessment has not changed
The existing EMAQ+ scoring system has been retained. A score below 20 indicates low-level odour control, a score between 20 and 35 indicates high-level control, and a score above 35 indicates very high-level control. The scores assigned to dispersion, receptor distance, kitchen size and cooking type are also unchanged.
The additional case studies are therefore more important than they may initially appear. The number has increased from four to thirteen and the new examples cover:
- Rising ground and receptors located close to stack height.
- Large commercial kitchens whose scale is not adequately represented by cover numbers alone.
- Discharges into recessed or semi-enclosed areas.
- Low-level discharges in dense mixed-use developments.
- Positive-pressure ductwork and leakage around filter housings.
- Poorly designed discharge terminals.
- UV-C performance and maintenance.
- Enhanced Best Practicable Means where a high-level stack cannot be installed.
These examples demonstrate the limitations of the numerical assessment. The risk score was developed around a relatively conventional high street setting. It cannot fully represent the effects of rising ground, surrounding buildings, enclosed service yards or unusually large cooking operations.
The score should therefore be treated as the starting point for the assessment, not the conclusion. The report still needs to explain whether the physical circumstances are adequately represented by the selected scores.
This is particularly relevant to the very poor dispersion category. There will be situations where dispersion is materially worse than the 20-point score can represent. Additional abatement may reduce the risk, but it does not necessarily make a fundamentally unsuitable discharge location acceptable.
Planning and regulatory context
The planning section was updated to refer to the December 2024 National Planning Policy Framework, Class E uses, late-night refreshment licensing and the agent of change principle.
The agent of change discussion is relevant to both new kitchens and new sensitive development close to existing kitchens. Where residential accommodation is introduced near an established restaurant, the developer may need to demonstrate that acceptable conditions can be achieved without placing unreasonable restrictions on the existing business.
The planning references already require care. The August 2026 National Planning Policy Framework replaced the December 2024 version shortly after the EMAQ+ guidance was published. The agent of change and hot food takeaway provisions remain, but the structure and policy references have changed. The EMAQ+ planning chapter should therefore be read as background rather than a substitute for checking current national and local policy.
There are other parts of the document that show its age. The detailed text still refers to the Fire Precautions (Workplace) Regulations 1997, although the summary refers to the Regulatory Reform (Fire Safety) Order 2005. It also retains references to the Building Regulations 2000. The cost tables continue to use 2018 prices. They may show the relative relationship between technologies, but they should not be used for current budgeting.
What does this mean in practice?
The new guidance should improve commercial kitchen assessments, provided it is not used as a checklist.
- For designers, there is a greater emphasis on calculated extract rates, negative-pressure ductwork, particulate removal and evidence that the selected equipment is suitable for the actual airflow and cooking load.
- For consultants, assessments should distinguish between odour control, grease and smoke control, PM2.5 control, dispersion, noise and maintenance. These issues are related, but they are not interchangeable. Activated carbon should not be relied upon as the primary means of controlling PM2.5. An ESP should not be treated as the primary means of controlling gaseous odour. A high stack improves dispersion but does not reduce the quantity of pollution discharged.
- For local authorities, the guidance provides a stronger basis for requesting filter efficiencies, ESP sizing, carbon quantity, residence time, ozone management, maintenance access and a proper description of the discharge environment.
- For operators, the message remains much the same. Even a correctly designed system will perform poorly if filters, ESP cells, UV lamps, carbon media and ductwork are not properly maintained.
Conclusion
Overall, the 2026 guidance is a worthwhile improvement. It provides better technical information, is more closely aligned with current ventilation standards and recognises that commercial cooking can be a relevant source of PM2.5.
Its main limitation is that it identifies the PM2.5 issue without providing a complete method for assessing it. The next stage should be a proportionate framework that identifies when particulate control is required and what performance needs to be demonstrated.
Until then, the sensible interpretation is not that every commercial kitchen requires HEPA filtration or dispersion modelling. It is that controlling odour cannot automatically be assumed to control the wider air-quality effects of commercial cooking.
Sources
EMAQ+, Control of Odour and Noise from Commercial Kitchen Exhaust Systems, 5 September 2018 and third EMAQ+ edition, 20 May 2026
Ministry of Housing, Communities and Local Government, National Planning Policy Framework, August 2026
