A Guide for BREEAM Assessors: Indoor Air Quality (HEA 02) and Ventilation


  1. Contents
  2. Who is this guide for?
  3. What is BREEAM?
  4. BREEAM HEA 02: Indoor Air Quality
  5. BREEAM HEA 02 Indoor Air Quality: Ventilation
  6. Have ventilation pathways been designed to minimise ingress of pollutants?
    1. Land Use
    2. Existing Air Quality
      1. United Kingdom
      2. London
    3. Determination of risk and appropriate method
    4. Limitations
  7. Ventilation Design
  8. How to determine appropriate filtration for BREEAM HEA 02?
  9. How do you demonstrate compliance with Low VOC construction products?
  10. Post Construction Testing
  11. Indoor Air Quality Plan
  12. What is BREEAM POL 02 and how does it relate to BREEAM HEA 02?
  13. Greenavon Air Quality Consultants
    1. Make an Enquiry
  14. Office Address

Who is this guide for?

This page has been written for BREEAM assessors and it provides guidance on what sort of information may be required to support a BREEAM HEA 02 Indoor Air Quality assessment. The amount of information required is dependent on the development’s indoor air quality risk, which can be determined through evaluation of the development’s proposed use class and local air quality.

This guide provides information on how air quality might influence the design of ventilation systems. It should, however, be noted that Greenavon are not ventilation specialists and a suitably qualified ventilation specialist should always be consulted when designing any system.

If you need an air quality plan to access HEA 02 credits, you can make an enquiry with the form below. We are able to assist worldwide.

What is BREEAM?

The Building Research Establishment Environmental Assessment Method (BREEAM) is a world leading certification program and sustainability assessment method that is used to evaluate the environmental performance of buildings. Certification levels range from “Pass” to “Outstanding”, with higher levels indicating a greater level of environmental performance.

The purpose of BREEAM is to promote the sustainable design, construction, and operation of buildings and it considers a wide range of factors, including:

  • energy efficiency
  • water use
  • the health and wellbeing of occupants
  • pollution
  • biodiversity.

Becoming BREEAM certified include can dramatically reduce the environmental impacts of buildings, reduce carbon emissions and running costs, as well as improving the health and wellbeing of occupants. The BREEAM assessment method can be applied across the planet to virtually any building, with different versions for new buildings, existing building, and refurbishments. 

BREEAM HEA 02: Indoor Air Quality

BREEAM HEA 02 aims to promote and reward buildings that have good indoor air quality. By achieving indoor air quality credits, building designers and owners can demonstrate that they have taken steps to benefit the physical health, productivity, and comfort of occupants.

It is important to note that there are minor differences in the requirements for different BREEAM schemes, such as between New Construction and Non-Domestic Refurbishment. This guide, however, focuses primarily on the requirements for New Construction (2018). Under this scheme, there are up to 5 credits available for HEA 02, with the production of an Indoor Air Quality Plan a pre-requisite for accessing any credits.

The credits available for this scheme are as follows:

  • Indoor Air Quality Plan (prerequisite)
  • Ventilation (one credit)
  • Emissions from construction products (up to two credits + one exemplary)
  • Post-construction indoor air quality measurement (one credit)

The credits available for HEA 02 are also dependent on the stage of construction and fit out. Table 1 summarises which BREEAM HEA 02 credits are available depending on the construction stage.

TypeCredits AvailableRequired Criteria
Shell and CoreVentilation (1)Appropriate levels of ventilation (2a)
Simple Building (up to 3 credits)Ventilation (1)Appropriate levels of ventilation (2a) and ventilation pathways designed to minimise pollutant ingress (2b)
Emissions from construction product (2 +1)All
Fully FittedVentilation (1)All
Emissions from construction product (2 +1)All
Post construction testingAll
Table 1: Development type and BREEAM HEA 02 credit availability.

BREEAM HEA 02 Indoor Air Quality: Ventilation

The design of a ventilation system requires consideration from numerous perspectives including acoustic, energy efficiency and air quality, and the different considerations may have different requirements. A suitably qualified ventilation specialist should always be consulted when designing any system. To achieve the ventilation credits associated with BREEAM HEA 02, the criteria in Table 2 must however be demonstrated.

2.aProvide fresh air into the building in accordance with the criteria of the relevant standard for ventilation.Part F (ventilation) sets out the basic requirements for ensuring that buildings are ventilated in a way that provides adequate ventilation.
2.b Ventilation pathways are designed to minimise the ingress and build-up of air pollutants inside the buildingThis guide sets out a infomal risk-based method that could be used to assess whether suitable evidence has been provided. A ventilation specialist should, however, be able to explain how the system is desinged to acheive this credit.
2.c Where present, HVAC systems must incorporate suitable filtration to minimise external air pollution, as defined in BSEN 16798-3:2017. The specified filters should achieve supply air classification of at least SUP 2.This guide explains how the level of filtration varies with outdoor air quality.
2.d Areas of the building subject to large and unpredictable or variable occupancy patterns have carbon dioxide (CO₂) or air quality sensors specified.BREEAM gives examples of spaces with large and unpredictable occupancy patterns, including: Auditoria, Gyms, Retail stores or malls, Cinemas and Waiting rooms.
2.d.iIn mechanically ventilated buildings or spaces: sensors are linked to the mechanical ventilation system and provide demand-controlled ventilation to the space.Pass/ Fail
2.d.iiIn naturally ventilated buildings or spaces: sensors either have the ability to alert the building owner or manager when CO₂ levels exceed the recommended set point, or are linked to controls with the ability to adjust the quantity of fresh air, i.e. automatic opening windows or roof ventsPass/ Fail
2.eNatural ventilation provides adequate cross flow of air to maintain the required thermal comfort conditions and ventilation rates in accordance with CIBSEAM10.A ventilation specialist or heating consultant may be required to confirm this.
Table 2: Criteria associated with BREEAM HEA 02 ventilation credit

Have ventilation pathways been designed to minimise ingress of pollutants?

The locations of ventilation intakes and airflow pathways should be designed in accordance with any or a combination of the following methods, outlined in Table 3. The methods are taken directly from BREEAM technical guidance, with notes on application provided by Greenavon.

Locating the building’s air intakes and exhausts, in relation to each other and sources of external pollution, in accordance with the following best practice as appropriate:

PD CEN/TR 16798-4

2017BREFB 30 Ventilation for healthy buildings

Reducing the impact of urban air pollution (2011)

BREIP 9/14 Locating ventilation inlets to reduce ingress of external pollutants into buildings

These documents provide generic guidance on the siting of ventilation inlets.

CISBE’s TM21 guidance states that the user can “decide how much detail is required relative to the specific requirements and location of the building under consideration.”
Pollutant dispersion modelling can be used to inform the location of the building’s air intakes and exhausts in relation to each other and sources of external pollution. This can be achieved using either wind tunnel modelling or numerical modelling. Pollutant dispersion modelling in urban areas is complex, so it is important that the person carrying out the modelling is a competent individual.Numerical modelling undertaken in ADMS often supports air quality assessments for planning applications and so can often be used to support the ventilation strategy. However, it should be noted that ADMS and other gaussian dispersion models can struggle to accurately dispersion around buildings. At some sites, computational fluid dynamic modelling should be undertaken.
Positioning the building’s air intakes and exhausts at least 10m of horizontal distance apart.  

Positioning intakes at least 10m horizontal distance from sources of external pollution (including the location of air exhausts from other buildings).  

The building’s air intakes and exhausts should be located to reduce the risk of the intake air being contaminated by the exhausts.

Exhausts or other pollutant sources should not be discharged into enclosed spaces, such as courtyards, in which intakes are also located.

Positioning openable windows/ and background ventilators over at least 10m of horizontal distance from sources of external pollution (including the location of any building-related air exhausts).
Simple and distanced based criteria that will be appropriate for low-risk sites (For example, in buildings such as warehouses where exposure is transient)
Table 3: Location of Inlets and Air Flow Pathways to minimise ingress of pollutants

In providing a range of tools that can be used to determine whether a proposal’s ventilation has been designed to minimise the ingress of pollutants, BREEAM allows professional judgement to be used to determine the appropriate approach.

A development’s risk is determined by the building’s end-use, existing air quality in the local area, and other factors including the amount of pollution emitted from the proposal, its aspect and the complexity of the built urban environment. The determination of a development’s risk profile is not always straightforward and air quality specialists should be consulted when in doubt. A more ‘at risk’ development would likely require a greater level of evidence to prove the design is suitable.

The responsibility for the ventilation system lies with the M&E engineer, who is required to ensure that it aligns with relevant standards. Nevertheless, the M&E engineer should be able to confidently explain how the ventilation pathways been designed to minimise ingress of pollutants, in line with the relevant standards.

Land Use

Best practice Institute of Air Quality Management (IAQM) guidance provides indicative examples of what high, medium, and low risk land-uses might include. These are reproduced below:

“High sensitivity receptor
•Indicative examples include residential properties.  Hospitals, schools and residential care homes should also be considered as having equal sensitivity to residential areas for the purposes of this assessment.

Medium sensitivity receptor
• locations where the people exposed are workers relevant location would be one where individuals may be exposed for eight hours or more in a day). indicative examples include office and shop workers.

Low sensitivity receptor
• locations where human exposure is transient. • indicative examples include public footpaths, playing fields, parks and shopping streets.”

IAQM guidance focuses on the impact on human health; however, it should be noted that and non-human objects may require protection from air pollution. Examples of non-human receptors include exhibits in museums, computers in data centres and food preparation areas.

For buildings with low sensitivity use, it is judged that the ‘simple distanced based’ approach would be appropriate in most situations.

Existing Air Quality

Alongside the building’s use, existing levels of pollution are as important in determining a development’s risk. In the UK, judgments on whether air quality is acceptable or poor, are often made in comparison to the UK Air Quality Standards (AQS) for ambient air, or WHO guideline values. These are reproduced in Table 4 below.

PollutantAveraging PeriodUK AQS (μg.m-3)WHO guideline 2005 (μg.m-3)WHO guideline 2021 (μg.m-3)
Nitrogen dioxide (NO2)Annual Mean404010
Particulate Matter (PM10)Annual Mean402015
Particulate Matter (PM2.5)Annual mean10105
Note: this table only focuses on annual average air quality standards. Standards for shorter period also exist.
Table 4: UK Annual Average Air Quality Standards

For example, the requirements for filtration efficiency in BREEAM are based outdoor air quality levels (ODA), where:

  • ODA1: levels of pollution (NO2, PM2.5, or PM10) meet national or WHO guidelines.
  • ODA2: levels of pollution (NO2, PM2.5, or PM10) exceed national or WHO guidelines by up to 1.5.
  • ODA3: levels of pollution (NO2, PM2.5, or PM10) exceed national or WHO guidelines by more than 1.5.

Areas where either national or WHO guidelines are met could be considered Low risk, with areas where standards are exceeded by more than 1.5 identified as High risk. Whether or not a building targets national standards or WHO guidelines should be discussed with the client and an air quality professional.

Whilst an air quality assessment will likely be required to provide robust predictions of pollutant concentrations, useful estimates for the purpose of BREEAM could be made using freely available by non-experts. The approach would likely differ between London and the rest of the UK, due to availability of different data sources.

United Kingdom

The UK-AIR information resource provides predictions of background annual mean concentrations of NO2, PM2.5, and PM10 and other pollutants across the UK. Roadside predictions are available on some roads. This information can be viewed using Defra’s Interactive map.

A tutorial for getting data from this resource is shown in the video below and is also described in the BREEAM technical manual in the POL 02 section.

Video Tutorial: Using Defra’s maps to estimate air pollution

The ‘roadside’ data should be used, where available, if the building is located within 5m of a busy road, or up to 15m from a major junction or roundabout.

‘Background’ air quality describes pollution levels at location away from any major sources of pollution (e.g., quiet residential streets). AEA provides guidance on locations that can be defined as background. These are reproduced below:

  • >30 m from any very busy road (> 30,000 vehicles per day).
  • >20 m from a busy road (10,000 – 30,000 vehicles per day) or from any medium sized sources, e.g. petrol stations or ventilation outlets from catering establishments;
  • >10 m from any main road.
  • >5 m from anywhere where vehicles may stop with their engines idling.

The background pollution data could be used without further consideration where a building meets the criteria above.

It should be noted that there is no clear distinction between roadside and background sites. The transition is gradual and is affected by the urban built form. As such, if accurate predictions are required, a more detailed air quality assessment would likely be required and you should consult an air quality consultant.

Furthermore, if the site is located within an Air Quality Management Area, the site should be considered, at least, in the ODA 2 category.


Whilst the above approach can be used in London, the London Atmospheric Emissions Inventory (LAEI) provide predictions for NO2, PM10 and PM2.5 at 20m*20m resolution, across the capital. This dataset can provide a higher resolution and more reliable prediction of air quality at a site.

A superseded but interactive version of the dataset has been provided by Parallel. Otherwise, for the most up to date predictions, the video below sets out how this data can be sourced.

Video Tutorial: Using the LAEI to estimate pollution concentrations, in London

Determination of risk and appropriate method

Table 6 below sets out a simple framework for determining the risk level for medium and high sensitivity receptors, based on air pollution levels at the site.  It is anticipated that BREEAM assessors and M&E engineers could use this framework to make an informed judgement on what evidence might be required to support a BREEAM HEA 02 assessment.

Receptor SensitivityAir Pollution LevelsRisk
Medium (e.g. places of work)ODA 1Low
ODA 2Medium
ODA 3Medium
High (e.g. Schools, hospitals, dwellings)ODA 1Medium/ High
ODA 2Medium/ High
ODA 3High
Table 5: Determination of Risk for Medium and High-Risk Development.

Table 6 sets out what approach to determining ventilation requirements may be appropriate based on the identified level of risk.

Development RiskMinimum requirementsGold Standard
LowDistance based onlyConsideration of factors set out in CISBE TM21 and/or dispersion modelling
MediumDistance based + Consideration of factors set out in CISBE TM21 and/or dispersion modellingDispersion modelling or 9/14 Locating ventilation inlets to reduce ingress of external pollutants into building
HighConsideration of factors set out in CISBE TM21/ 9/14 Locating ventilation inlets to reduce ingress of external pollutants into buildings + Dispersion modellingComputer Fluid Dynamics or Wind Tunnel Modelling.
Table 6: Risk based approach to determine appropriate means of evidencing compliance with BREEAM HEA 02 Ventilation.

A BREEAM indoor Air Quality Plan should contain enough detail to allow the BREEAM assessor to clearly understand the development’s risk level, and what sort of evidence might be required to demonstrate that the proposal’s ventilation strategy has been designed to minimise the ingress of pollution. The Indoor Air Quality Plan should also guide how the development can be designed to minimise ingress of pollution, allowing the BREEAM assessor to use the plan to evaluate the design’s adherence to ventilation credits. It should, however, be stressed that it is the M&E engineer’s responsibility to provide evidence that the ventilation system is appropriately designed.

It should be noted that development in areas of poor air quality often require an air quality assessment to support the planning application and this document often contains information which can be used to guide the ventilation strategy.


The above points provide a very simple framework which can be used to estimate a development’s risk, which can be used to inform what type of evidence may be appropriate. The approach has limitations, which should be fully understood before use. For example, it should be stressed there are many additional factors which influence air quality and that are not included in the above framework. These include:

  • The urban built form, and whether the site is located in a ‘street canyon’ or near tunnels, or tall buildings.
  • The location of other sources of including bus stations, bus stops and commercial kitchen exhausts.
  • The aspect of the building relative to the prevailing wind
  • The prevailing wind direction.
  • How pollution levels change over time.
  • The development height – air pollution in urban areas generally falls with height.

Without undertaking a very detailed assessment for every development, there will always be some uncertainty whether the ventilation strategy is optimal.

Ventilation Design

The Indoor Air Quality Plan should set out best practice design features, reflective of the stage of development, which will allow the BREEAM assessor to ascertain whether the design meets best practice. Considerations for ventilation design, taken from CISBE TM21 guidance, include the following:

  • If practicable, ventilation intakes should not be in courtyards or enclosed spaces where air pollutants are discharged.
  • Air inlets should be placed at height or at roof level in urban areas, as NO2 levels tend to reduce with increased distance away from the road.
  • Ventilation should be provided from the non-road facing façade, where pollution levels will generally be lower.
  • Secondary sources of pollution should be moved away from inlets, where possible. These sources may include: roosting ledges for birds, soil and boiler flues.
  • In areas where wind comes from opposing directions, the air intake should point in the opposite direction to the exhaust outlets.
  • There are controls on the ventilation system which allow different rates of ventilation at different times of day.
  • Exhausts should discharge vertically, be uncapped and be grouped into a single cluster, where appropriate, to promote effective dispersion.
  • Exhaust outlets should not be discharge into courtyards, enclosures or architectural screens.
  • Where wall exhausts rather than roof exhausts are used, they should be located on the upper one-third of a building façade.
  • Wherever possible, inlets and exhausts should not be near the edges of walls or roofs due to pressure fluctuations in those areas.

How to determine appropriate filtration for BREEAM HEA 02?

To achieve concentrations of pollutants below the 2005 WHO guidelines and meet the requirements of BREEAM HEA 02, filtration must be provided for mix mode and mechanically ventilated buildings in line with BSEN 16798-3:2017. The required efficiency of filter is dependent on ambient pollution concentrations in the area.

Tables 7 an 8 outline the required filter efficiency, and recommendations for gas filtration based on outdoor air quality.

Outdoor Air QualityFilter Efficiency %
ODA 188%80%
ODA 296%88%
ODA 399%96%
Table 7: Required filtration efficiency based on Outdoor Air Quality
Outdoor Air QualityGas Filter
ODA 1RecommendedNot required
ODA 2RequiredRecommended
ODA 3RequiredRequired
Table 8: Recommendations for gas filtration based on Outdoor Air Quality

How do you demonstrate compliance with Low VOC construction products?

Construction products, as well as paints and furnishings can be a major source of indoor air pollution, particularly volatile organic compounds (VOCs) and formaldehyde. BREEAM guidance notes include a list of certification schemes that have demonstrated they meet the required emission standards. These schemes include:

  • Danish Indoor Climate Labelling-Class 1
  • Danish Indoor Climate Labelling-Class 2
  • eco-INSTITUT-Label
  • FloorScore®
  • GREENGUARD Certified¶
  • GUT
  • Indoor AdvantageTM Gold – Building Materials
  • Indoor Air Comfort®
  • Indoor Air Comfort Gold®
  • M1 Emission Classification of Building Materials
  • natureplus® eco-label

This list is not exhaustive and products must be able to demonstrate compliance with SCS Global’s “Verification Guidelines: Post-November 2015 Launched BREEAM and HQM scheme requirements for Emissions from Building Products – ECS Indoor Air Quality Technical Guidance Document 002”.  Products intended for use in wet areas (e.g. bathrooms, kitchens, utility rooms) must also provide evidence that they protect against mould growth.

Post Construction Testing

For fully fitted buildings there is a credit for post-construction monitoring. The monitoring aims to ensure that pollution concentrations are sufficiently low to allow occupation of the building. Post construction monitoring must be undertaken after the building has been “flushed out” with sufficient air to minimise the risk of failure.

BREEAM HEA 02 dictates that concentrations of total volatile organic compounds (TVOCs) and formaldehyde should be monitored, as a minimum.

It is advised that monitoring should be carried out in rooms that would be occupied for long periods of time, such as bedrooms, living rooms, classrooms, and offices.

Post-construction monitoring is not required in all rooms, and instead a representative number of rooms should be selected considering the size of the building and differences in ventilation strategy and construction products across the building.

Other pollutants such as NO2 and PM10/PM2.5 may also need to be considered depending on local conditions. By conducting post-construction monitoring, building owners and occupants can ensure that the indoor environment is healthy and safe. This monitoring process can help identify any potential indoor air quality issues that need to be addressed, such as the need for additional ventilation or remediation works.

Indoor Air Quality Plan

An Indoor Air Quality Plan should be considered at the earliest stages of design because it can have a significant impact on the health and well-being of building occupants, as well as the energy efficiency and sustainability of the building.  By considering air quality at the earliest stages of design, architects and engineers can integrate strategies to promote good air quality into the building design, which can reduce the need for costly retrofitting or modifications later.

As a minimum, a BREEAM Indoor Air Quality (IAQ) plan needs to consider the following aspects:

  1. Removal of contaminant sources
  2. Dilution and control of contaminant sources:
  3. Procedures for pre-occupancy flush out
  4. Third party testing and analysis
  5. Maintaining good indoor air quality in-use.

The Indoor Air Quality Plan should act as a manual that will allow BREEAM assessors to rigorously evaluate the indoor air quality credentials of the final plans. As such, the IAQP must also include:

  • A summary of relevant air quality standards and guidelines for the development type.
  • An assessment of baseline air quality.
  • An identification of the project’s risk and likely evidential requirements to achieve other BREEAM HEA 02 credits.

The level of detail required in an IAQP will be dependent on the construction stage, with fully fitted building needing a more comprehensive plan than a shell and core development.  By considering these aspects, a BREEAM IAQ plan can remove the barriers to BREEAM assessors targeting the credits and promote healthy air quality in buildings.

What is BREEAM POL 02 and how does it relate to BREEAM HEA 02?

Combustion process can produce pollutants such as carbon monoxide, nitrogen oxides, and particulate matter, which can be harmful to human health if they are not properly vented to the outside air.

POL 02 is a BREEAM credit that relates to local air quality and the setting of emission limits for combustion plant. The emission limits for this credit are dependent on outdoor air quality as well as the selected fuel type.  All credits can be achieved, if all heating and hot water is supplied by non-combustion systems (e.g. electric boilers or air source heat pumps).   

Care should, however, be taken to ensure that emission limits from other regulatory frameworks are also adhered to. For example, in London, the use of solid fuels has effectively been banned through the Greater London Authority’s air quality neutral policy.

Whilst not directly related to BREEAM HEA 02 and indoor air quality, emissions from any combustion plant on-site will contribute to elevated ambient concentrations. A major source of pollution on-site could cause indoor air quality issues if the extract air is drawn back into the building. Therefore, it is important to ensure that combustion plant exhausts are properly vented to the outside air and do not enter the HVAC system. This can be achieved by the creation of an appropriate ventilation strategy that complies with relevant regulations and standards, including BREEAM’s HEA 02 credit.

Greenavon Air Quality Consultants

Greenavon provides expert support for achieving BREEAM indoor air quality credits. We understand that achieving good indoor air quality is crucial for the health and well-being of building occupants and for attaining BREEAM certification.

Our team of experienced professionals offers a free consultation to guide you through the BREEAM indoor air quality requirements and to provide customized solutions for your specific building needs. Our approach is holistic, taking into account all aspects of indoor air quality, including ventilation systems, emissions from building materials, occupancy patterns, testing and monitoring, maintenance and cleaning, and communication and education.

If you are looking to achieve BREEAM certification and want to ensure that your building meets the required indoor air quality standards, get in touch with Greenavon today to take advantage of our free consultation and expert support.

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