indoor air quality

What affects indoor air quality?

While most people understand the dangers of breathing in polluted air such as smog or traffic fumes while outdoors, the risks associated with poor quality indoor air are less well known. In fact, indoor air quality can often be poorer than outside.

Workplaces and other shared public spaces can be particularly prone to issues with poor air quality. As well as frequently making buildings unpleasant places to spend an extended period of time, poor air quality can have serious health consequences. Poor indoor air quality has been linked to lung diseases such as asthma, COPD and lung cancer. It has also been linked to an increased risk of heart disease and stroke.

In the UK, poor air quality is considered a severe environmental risk with air pollution leading to an estimated 40,000 early deaths every year. For this reason, building owners and managers need to ensure that they have a coherent and effective strategy in place to manage indoor air quality.

Types of Air Pollution

The types of air pollution include:

  • Particulate matter – these are tiny particles of dust and dirt in the air such as soot and dust mites.
  • Volatile Organic Compounds (VOC) – these include both synthetic and natural chemicals such as formaldehyde and can arise from a variety of sources such as cleaning agents, construction products pain and electrical goods.
  • Allergens – these are biological particles that can cause an allergic response in some people. The principal sources of allergens are fungal particles, dust mite excrement and pollen. The levels are elevated in humid, damp buildings.
  • Gases – these include carbon monoxide, nitrogen oxide and sulphur dioxide.

Factors that influence indoor air quality

The levels of indoor air pollution depend on a range of external as well as internal factors. These include behaviours such as smoking and geographic factors such as whether the building is in close proximity to a busy road or junction. There are other factors that can have an impact such as industrial processes taking place nearby or environmental elements such as radon gas.

Pollutants that are generated inside a building often arise from building materials, furniture and furnishings. Activities that take place inside the building can play a part such as smoking, cooking, heating and the use of cleaning products and air fresheners.  

Pollutants from outside the building can be caused by traffic emissions and industrial processes that migrate indoors through windows or inadequate ventilation that doesn’t keep air circulating.

It’s also important to remember that the air quality can differ from room to room. Some rooms, particularly those which have close proximity to a busy road, may have much poor air quality than one in another part of the building that overlooks green open space.

indoor air quality

Another important factor in determining indoor air pollutant concentrations is the air exchange rate with the outdoors. This is affected by the design, construction and overall operating parameters of the building and is a function infiltration. This is the air that flows into a structure through cracks in walls, ceilings, floors, joints and around windows and doors. Natural ventilation, as well as mechanical ventilation such as that provided by an efficient HVAC system, will also impact the air exchange rate.

The external climate and overall weather conditions can also affect indoor air quality. Weather conditions will, to some extent, determine the behaviour of the building’s occupants, influencing whether or not they keep windows open or closed and whether they operate air conditioners, heaters or humidifiers. All of these will have an effect on the air quality in the building. Certain climatic conditions can considerably increase the potential for mould growth and indoor moisture if they are controlled through ventilation or air conditioning.

How to improve indoor air quality

Adequate airflow and ventilation are key to improving indoor air quality. This can be achieved through a level of natural ventilation, but this has its limits. With the UK climate it’s not always realistic to open windows and doors during the colder months and increasing the heating to compensate is inefficient and costly. If a room is located next to a busy road then opening windows can be counterproductive, leading to increased levels of indoor pollution.

How to make indoor air quality better in public spaces

Removing contaminants, and the cause of issues such as mould, should be considered wherever possible and when chemicals or cleaning products are being used indoors, adequate extra ventilation should be assured.

Ultimately, to properly tackle overall indoor air quality, well-designed and efficient mechanical HVAC systems should be installed. Indoor air quality should be a factor taken into consideration at the initial design and commissioning stage. Any HVAC system that’s in place should be regularly tested to ensure that it’s working at its full potential.

In some cases, particularly in older buildings or buildings that have undergone a change of use, retro-commissioning might be appropriate. This is a detailed and systematic process through which the efficiency of an existing building’s equipment and systems is improved.

ECS Yorkshire is one of the UK’s leading HVAC commissioning, retro and re-commissioning companies.

To find out more about how we can assess and improve the air quality in your building, call 01535 or email today.