Ventilation matters - why clean air is vital to health

How do buildings affect health?

The buildings and indoor environments we use every day can have an impact on our health. Building design, layout, and the facilities available can all affect the freshness of the air, as well as factors including:
  • Space/crowding
  • Noise
  • Temperature
  • Light
It is important to keep the ‘lungs’ of our buildings healthy so they can keep us healthy too.
Illnesses can be easily passed between people either from contaminated surfaces or through the air when people with infections talk, cough, or sneeze. When people gather in indoor spaces pollutants can build up making the environment unhealthy; unless action is taken buildings become susceptible to stagnant air, where infectious diseases and carbon dioxide can make the indoor air more polluted than the air outside and infections can be passed from person to person more easily.
Reducing the risk of infections and other health conditions requires both management of indoor spaces and the air in them, including regular cleaning and effective ventilation. It can be easier to see when physical surfaces are unclean, but air quality is often invisible and poorly understood, so risks are too often unmanaged until there is a problem.
Effective ventilation is essential to protecting public health – buildings need to be able to “breathe” and get a supply of fresh air. Preventing the spread of infections in the first place is better than trying to manage illness, and people should be able to have confidence that the air in the buildings they use is safe to breathe. You wouldn't want to drink dirty water so neither should you want to breathe in dirty air!

Why does ventilation matter to me?

Fresh air is important for health, not only to reduce exposure to airborne disease, but to ensure we are getting enough oxygen to support our health. People spend onaverage 80% of their time indoors, more so during the colder winter months, and good ventilation can significantly reduce exposure to diseases. Spending time in poorly ventilated spaces can cause reactions due to reduced oxygen levels such as:
  • Headaches
  • Tiredness
  • Lower concentration levels
In industrial premises, it is important to ensure that enough fresh air is supplied to dilute and remove by-products such as dust, fumes or vapour.

Benefits of ventilation for building users

Reduced risk of respiratory illnesses and allergic reactions such as asthma by removing large particles and dust and preventing build-up of mould
Reduced risk of spreading and catching diseases such as flu, and COVID-19
Improved mental health and supporting better sleep

Benefits of ventilation for employers

Less illness and fewer related absences
Fresher air improves productivity and concentration of employees and students
Protection against build-up of moisture and mould which can contribute to ill health

Warning signs of bad ventilation

If the air feels “stuffy” or the room feels too hot
If the air smells unpleasant and is not dissipating
If the room feels “muggy” or there is any condensation or damp
If there is any mould growth [and this will need to be properly treated]
Alerts by monitors such as CO₂ monitors

Key studies, statistics on ventilation

How can rooms be ventilated - knowing how to identify the ventilation options in a room

Ventilation is about bringing fresh air to indoor spaces. There are various ways to ventilate a space depending on the type of room or building, its size and layout, and what the space is used for. The benefits of ventilation are greatest in rooms where people spend more time together and where lots of people are mixing.

The amount of ventilation or ventilation time, required to completely refresh air in a room will depend on specific circumstances, including the size and use of the room.


There are tools that can support risk assessments for air quality: Detailed guidance on the appropriate ventilation rates for a wide range of specific building types:

Types of ventilation

Natural ventilation uses openings such as windows or vents to bring fresh air indoors. The simplest and most common way to promote natural ventilation is opening doors and windows, but ventilation is also helped by using trickle vents in windows, air bricks, or wall vents.

Natural ventilation is commonly used in:
  • Flats and houses,
  • Small shops and restaurants
  • Community buildings like churches, libraries, community town halls etc
Mechanical ventilation uses technology and mechanically driven fans, to move air into, out from and around a building.
To help manage heating, cooling, and humidity control along with ventilation, these systems may use an integrated system for heating, ventilation and air conditioning (HVAC).
Ventilation is not the same as air conditioning.

Mechanical ventilation is commonly used in
  • Factories
  • Offices
  • Retail and leisure buildings
  • Hospitals
  • Prisons etc.
In some cases, these ventilation systems are overseen by the building or facilities manager [who can advise on the available facilities]. Local exhaust ventilation (LEV) systems offer protection by transporting contaminants away from users/employees, including in industrial settings.
Hybrid or mixed mode ventilation uses both natural and mechanical methodsuses both natural and mechanical methods and can help to balance the demand for fresh air, while reducing the electricity needed to operate the ventilation systems.
Air cleaning technologies can be used in spaces where good ventilation is not possible, and can be used to filter air and can reduce health risks while reducing energy costs. HEPA filter and UVC air cleaners can be an effective and low energy (and low carbon) way of reducing exposure to pollutants. To find out which technologies will work, seek advice from building engineering professionals on suitable solutions.

Different building types

Different building types have different characteristics and uses. They may require different ventilation strategies using natural, mechanical or hybrid ventilation strategies. Ventilation is a legal requirement for buildings in the UK under workplace regulations, risk assessments should include ventilation and consider the needs of the given space.

different building types preview

Managing ventilation - what can I do

Use the key below to explore actions that can be taken to improve ventilation, you can search by user or by types of ventilation facilities that you have available. Click the dots to find out what you can do and view the resources provided if you would like to explore further.
Choose Types of ventilation you have
Natural ventilation
Mechanical ventilation
Hybrid ventilation
Inadequate ventilation