Guidance

Recommendations

Recommendations

People have the right to be involved in discussions and make informed decisions about their care, as described in NICE's information on making decisions about your care.

Making decisions using NICE guidelines explains how we use words to show the strength (or certainty) of our recommendations, and has information about prescribing medicines (including off-label use), professional guidelines, standards and laws (including on consent and mental capacity), and safeguarding.

Box 1 People who may be particularly vulnerable and factors that increase the risk of ill health due to exposure to poor indoor air quality

People who may be vulnerable

People who may be particularly vulnerable to ill health as a result of exposure to poor indoor air quality include:

  • people with a pre‑existing health condition such as asthma, allergies, chronic obstructive pulmonary disease (COPD) and cardiovascular disease

  • pregnant women and their unborn babies

  • pre-school children

  • older people

  • people who live in poor-quality housing

  • people exposed to tobacco smoke in their homes

  • people who live in poverty.

Housing conditions

Housing conditions that put people at increased risk of exposure to poor indoor air quality include:

  • location (external factors such as high levels of outdoor air pollution, or where noise or security risks mean residents do not open windows)

  • physical infrastructure (such as small room size, inadequate ventilation and the building's layout and orientation)

  • standard of housing (for example, with damp and mould or physical disrepair including flood damage or with unflued or poorly maintained fuel-burning appliances)

  • overcrowding.

There are a number of activities that might contribute to poor indoor air quality (see the section on advice and information for the general population).

For the purposes of this guideline, the term 'local authorities' covers all types of local authority in England; these are county councils, district councils, unitary authorities, metropolitan districts and London boroughs. Each local authority should decide which of the following recommendations are relevant to their local responsibilities.

1.1 Prioritising indoor air quality in local strategy or plans

These recommendations are for local authorities.

1.1.1 Embed a plan for improving indoor air quality in an existing strategy or plan to improve people's health. This could be a general air quality strategy if one exists. Otherwise, for example, include it in a strategy on housing, health and wellbeing, or inequalities.

1.1.2 Ensure the strategy or plan takes account of the housing conditions that put people at increased risk of exposure to poor indoor air quality and especially people who are particularly vulnerable to ill health as a result of such exposure (see box 1).

1.1.3 Emphasise the need for a balanced approach to ventilation, insulation and heating for good indoor air quality. (See the sections on raising awareness of poor indoor air quality in the home and advice and information for the general population, and NICE's guideline on winter deaths and illness and cold homes.)

1.1.4 Encourage joint working between local authority departments, across different local authorities, with local health and social care providers, and with voluntary, community and social enterprise organisations and other organisations with interest in indoor air quality, to improve air quality in people's homes (see the sections on raising awareness of poor indoor air quality in the home and advice and information for the general population).

1.1.5 Encourage the use of existing home visits to identify poor indoor air quality. For example, visits to people's homes by housing officers, environmental health practitioners, community health services, social workers, care workers, and fire and rescue services.

1.1.6 Encourage the use of local inspection protocols to identify poor indoor air quality during home visits. This may include visual inspections, checklists and the monitoring of pollutant levels. Use this information to identify other homes that may be at increased risk of poor indoor air quality.

1.1.7 Encourage joint working with external organisations to inform home improvement programmes and identify grants to combat poor indoor air quality.

1.1.8 Monitor progress against the goals of the strategy. Use audit data (see the recommendation on encouraging the use of existing home visits in this section) plus the lists in box 1 to identify people who may be vulnerable and properties that are at risk.

For a short explanation of why the committee made these recommendations and how they might affect practice, see the rationale and impact section on prioritising indoor air quality in local strategy or plans.

Full details of the evidence and the committee's discussion are in:

1.2 Referrals for a housing assessment

These recommendations are for local authorities.

1.2.1 Develop a structured process so that health and social care professionals and housing and local authority staff can use existing referral pathways to help people request a housing assessment if poor indoor air quality has been identified or is suspected, for example, by using the housing condition factors in box 1.

1.2.2 Advise health and social care professionals and housing and local authority staff on how to help people request a housing assessment if poor indoor air quality is identified or suspected, for example, by using the housing condition factors in box 1.

For a short explanation of why the committee made these recommendations and how they might affect practice, see the rationale and impact section on referrals for a housing assessment.

Full details of the evidence and the committee's discussion are in:

1.3 Raising awareness of poor indoor air quality in the home

These recommendations are for local authorities.

1.3.1 Use existing communication strategies to ensure members of the public and relevant professionals (those involved in planning, designing, building, renovating and maintaining homes) are aware of:

  • the causes of poor indoor air quality

  • how residents' activities can affect indoor air quality

  • how health is affected by poor indoor air quality

  • who is particularly vulnerable (see box 1)

  • how to prevent or reduce poor indoor air quality.

1.3.2 Use existing professional development opportunities to ensure local authority staff who visit people in their homes (such as housing, healthcare and social care professionals):

For a short explanation of why the committee made these recommendations and how they might affect practice, see the rationale and impact section on raising awareness of poor indoor air quality in the home.

Full details of the evidence and the committee's discussion are in evidence review 4: effective strategies for raising awareness.

1.4 Advice and information for the general population

These recommendations are for local authorities.

1.4.1 Advise people on how to reduce damp and condensation and prevent mould. For example, by:

  • using background ventilation (such as trickle vents, or whole-house mechanical ventilation systems)

  • using mechanical ventilation (such as extractor fans), and opening windows where possible and safe to provide temporary increased ventilation

  • avoiding moisture-producing activities (such as air-drying clothes) indoors if possible, or improving ventilation if these cannot be avoided

  • repairing sources of water damage and ensuring that residual moisture is removed.

1.4.2 Advise people on how to use trickle vents correctly.

1.4.3 Tell people that the following activities may lead to poor indoor air quality and that they should think about increasing ventilation (by using extractor fans in the bathroom or kitchen, or opening windows if possible and safe):

  • using cookers, especially gas cookers

  • using open solid-fuel fires

  • using candles

  • using free-standing gas heaters

  • using cleaning products, household sprays or aerosols and paints

  • having a bath or shower

  • air-drying clothes in the home.

1.4.4 Advise private and social tenants to contact their landlord if:

  • ventilation is not adequate (for example, if the ventilation system is not working, trickle vents are blocked or damaged, extractor fans in the kitchen or bathroom are not working, or if excessive noise from the fans discourages their use)

  • repairs are needed to prevent water from entering their building

  • improvements to heating or insulation are needed to prevent condensation.

1.4.5 Advise private and social tenants to contact their local authority if no action is taken to improve ventilation or carry out repairs (see the government guides on private renting and council housing, and the Guide for tenants: Homes [Fitness for Human Habitation] Act 2018).

1.4.6 Advise people not to use unflued paraffin heaters in the home.

1.4.7 Advise people to follow the product instructions when using, for example, candles, paints, glues and solvents, to minimise exposure to pollutants.

1.4.8 Advise people to choose low-emission materials (for example, products with a low volatile organic compound [VOC] or formaldehyde content and emissions) if furniture or flooring needs replacing.

1.4.9 Advise people installing a new cooker about the need for ventilation, especially for gas cookers.

1.4.10 Advise people not to use gas cookers to heat a room.

1.4.11 Encourage people not to smoke in the home (see NICE's guidelines on stop smoking interventions and services and smoking: stopping in pregnancy and after childbirth).

Also see the section on healthcare professionals' advice for women who are pregnant or who have given birth in the past 12 months (see the section on healthcare professionals) and the section on advice for property managers and landlords (see the section on rental properties).

For a short explanation of why the committee made these recommendations and how they might affect practice, see the rationale and impact section on advice and information for the general population.

Full details of the evidence and the committee's discussion are in:

1.5 Healthcare professionals

People with asthma, other respiratory conditions or cardiovascular conditions

1.5.1 Explain that indoor air pollutants (including nitrogen dioxide, damp, mould, particulate matter and VOCs) can trigger or exacerbate asthma, other respiratory conditions or cardiovascular conditions.

1.5.2 If a person has repeated or worsening respiratory symptoms such as a cough or wheezing, ask about their housing conditions. If these are a concern, help them request a housing assessment from the local authority (see the section on referrals for a housing assessment).

1.5.3 Advise people whose asthma is triggered by household sprays, air fresheners or aerosols to:

  • avoid using them

  • use non-spray alternatives.

Also see the section on advice and information for recommendations about ventilation and controlling sources of pollution (see the section on advice and information for the general population) and NICE's guideline on asthma.

People who are allergic to house dust mites

1.5.4 Advise people who are allergic to house dust mites how to reduce their exposure to them. This includes:

  • avoiding second-hand mattresses if possible

  • using allergen barriers such as mattress and pillow covers

  • washing bedding regularly.

Also see the section on advice and information for recommendations about ventilation and controlling sources of pollution (see the section on advice and information for the general population) and NHS advice on allergen avoidance.

Women who are pregnant or who have given birth in the past 12 months and partners and people who live with them

1.5.5 Ask about the person's housing conditions. If housing factors are a health concern, for example, because of damp or lack of ventilation, help them request a housing assessment from the local authority (see the section on referrals for a housing assessment).

1.5.6 Advise women who are pregnant that they are at increased risk of ill health from exposure to poor indoor air quality. Advise people who care for babies under 12 months old that the baby is at increased risk. Both groups should:

  • reduce their use of household sprays, air fresheners and other aerosols, and always follow product instructions

  • if possible, avoid or reduce activities that produce particulate matter such as using open solid-fuel fires or candles

  • always keep the room well ventilated during these activities.

    See also recommendations 1.4.3, 1.4.4, 1.4.6 and 1.4.8.

1.5.7 Explain that other people's tobacco smoke is a risk to a woman who is pregnant and her baby, before and after birth. Advise not smoking in the home or around the woman and her baby. (Also see NICE's guideline on smoking: stopping in pregnancy and after childbirth.)

For a short explanation of why the committee made these recommendations and how they might affect practice, see the rationale and impact section on healthcare professionals.

Full details of the evidence and the committee's discussion are in:

1.6 Regulators and building control teams

1.6.1 Update existing standards, for example building regulations, or develop new ones for indoor air quality. Base them on current safe limits set for pollutants in residential developments. See, for example, World Health Organization guidelines on selected pollutants (2010) and dampness and mould (2009), and the Public Health England indoor air quality guidelines for selected VOCs (2019).

1.6.2 Use existing building regulation enforcement activities to improve indoor air quality. Ensure enforcement takes place within the specified timelines. (See the government's Building Regulations 2010 and Housing health and safety rating system operating guidance, and the Planning Portal's failure to comply with the building regulations.)

For a short explanation of why the committee made these recommendations and how they might affect practice, see the rationale and impact section on regulators and building control teams.

Full details of the evidence and the committee's discussion are in:

1.7 Architects and designers

Avoiding sources of pollutants

1.7.1 Consider specifying building materials and products that only emit a low level of formaldehyde and VOCs. Use existing labelling schemes or other available information on product emissions (for example, on product labels) to make these specifications.

1.7.2 Design or specify heating systems that minimise indoor exposure to particulate matter.

Heating and ventilation

1.7.3 Adopt a whole-building approach to heating and ventilation to ensure indoor air quality is maintained while achieving standards for energy use. (Also see NICE's guideline on winter deaths and illness and cold homes.)

1.7.4 Ensure design strategies include provision for removing indoor air pollutants, for example by:

1.7.5 Design ventilation systems to reduce or avoid exposure to outdoor air pollution. For example:

  • ensure windows that open face away from sources of outdoor air pollution, such as busy roads

  • fit mechanical systems with filtration to protect against outdoor pollutants. (Also see the government clean air strategy 2019.)

1.7.6 When building dwellings or refurbishing them to improve thermal performance, ensure there is permanent, effective ventilation.

For a short explanation of why the committee made these recommendations and how they might affect practice, see the rationale and impact section on architects and designers.

Full details of the evidence and the committee's discussion are in:

1.8 Builders, contractors and developers

These recommendations apply both to building new homes and renovating or refurbishing existing homes.

1.8.1 Ensure products and materials comply with building regulations, design specifications and the manufacturer's guidance on installation and commissioning.

1.8.2 Use materials that emit a low level of formaldehyde and VOCs as specified. If materials need to be substituted, only use products with the same or lower emission levels.

1.8.3 Ensure all heating and ventilation is installed and commissioned in accordance with the manufacturer's instructions and meets building regulation requirements.

1.8.4 Ensure all installed heating and ventilation systems are easily accessible for regular maintenance.

1.8.5 Ensure any variations to the heating and ventilation specification comply with design specifications and building regulations (see the Ministry of Housing, Communities and Local Government's advice on ventilation).

For a short explanation of why the committee made these recommendations and how they might affect practice, see the rationale and impact section on builders, contractors and developers.

Full details of the evidence and the committee's discussion are in evidence review 3.1: material and structural interventions.

1.9 Rental properties

These recommendations are for local authorities and cover both private and public rented housing.

Regulations

1.9.1 Use existing regulatory powers to:

1.9.2 Where a housing assessment has identified problems in private or public rented housing that may contribute to poor indoor air quality, ensure the property has:

  • heating appliances and ventilation systems that:

    • comply with design and performance requirements

    • are correctly installed and tested

    • keep properties warm and ventilated without excessive heat loss or draughts

  • ventilation that prevents the build‑up of pollutants, including:

    • trickle vents

    • working mechanical ventilation systems, such as extractor fans, in bathrooms and kitchens

    • windows that open (but not onto busy roads or other major sources of outdoor air pollution)

  • cooking appliances that:

    • comply with design and performance requirements

    • are correctly installed and tested.

1.9.3 Where a housing assessment has identified water damage in private or public rented housing, ensure that any water damage is repaired as soon as possible and the property has properly dried out.

Property management

1.9.4 Advise property managers and landlords to:

  • develop and undertake maintenance programmes for heating and ventilation systems

  • provide clear, easy-to-understand instructions telling residents how to use the heating and ventilation systems effectively.

1.9.5 Advise property managers and landlords about:

  • the health risks associated with poor indoor air quality

  • methods to control and minimise identified sources of indoor air pollution (see the section for architects and designers)

  • their responsibilities for maintaining the property.

1.9.6 Advise property managers and landlords to:

  • use low-pollutant-emission items when replacing furniture or flooring (for example, furniture or flooring with a low formaldehyde content and emission)

  • ensure rooms are well ventilated and that the manufacturer's guidelines for use of materials are followed

  • ensure there is adequate ventilation provision before installing a new cooker (especially a gas cooker).

For a short explanation of why the committee made these recommendations and how they might affect practice,see the rationale and impact section on rental properties.

Full details of the evidence and the committee's discussion are in:

Terms used in this guideline

This section defines terms that have been used in a particular way for this guideline. For other definitions, see the NICE glossary or, for public health and social care terms, the Think Local, Act Personal Care and Support Jargon Buster.

Particulate matter

Particulate matter (also referred to as PM or particle pollution) is a complex mixture of solid or liquid particles suspended in air. These particles can vary in size, shape and composition. Indoor particulate matter can be generated through cooking, combustion (including candles, open solid-fuel fires, unvented space heaters or paraffin heaters) and smoking.

Purge ventilation

Manually controlled ventilation of rooms or spaces at a relatively high rate to rapidly dilute pollutants or water vapour, for example by opening a window or using a fan.

  • National Institute for Health and Care Excellence (NICE)