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Last edited 15 Jun 2018
Indoor environmental quality
With people generally spending more time indoors, and buildings being more tightly constructed and isolated from the external environment, a greater importance is being placed on the indoor environment.
Indoor environmental quality (IEQ) is a general indicator of the quality of conditions inside a building. It can also include functional aspects of space, for example whether the layout provides access to equipment when needed and whether the building has sufficient space for its occupants.
A better indoor environmental quality can enhance the wellbeing of building occupants and help decrease the occurrence of sick building syndrome and building related illness. It can also lead to a decrease in worker complaints and absenteeism which in turn can improve productivity.
 Factors influencing indoor environmental quality
The indoor building environment is complex and there are a variety of factors that can influence its environmental quality.
- Airborne contaminants (gases and particles) from; office equipment, cleaning products, construction activities, furnishings and carpets, water-damaged building materials, microbial growth (fungal, bacterial and mould), outdoor pollutants, and so on.
- Indoor air quality.
- Thermal comfort.
- Daylight, lighting and views.
- Electromagnetic frequency levels.
- Acoustic conditions.
 Optimal indoor environmental quality design
In order to optimise indoor environmental quality, the design and development process should:
- Ensure good quality design, construction, commissioning, operating and maintenance practices.
- Consider aesthetic designs including the importance of views and the integration of natural elements.
- Provide thermal comfort controls for occupants where possible.
- Supply adequate levels and quality of ventilation.
- Prevent airborne bacteria, mould and other fungi through a design that manages moisture sources inside and outside the building.
- Use building products that do not emit pollutants.
- Use sound absorbing/insulating materials to help create optimal acoustic levels.
 Building management to improve indoor environmental quality
There are a number of ways that the indoor environmental quality of existing buildings can be improved, including:
- Using fragrance-free and low VOC (volatile organic compounds) cleaning products.
- Undertaking audits of cleaning products and devising a cleaning plan to replace products with safer alternatives.
- Vacuuming regularly and using vacuums with HEPA (High-efficiency particulate arrestance) filters.
- Ensuring that HVAC equipment is well maintained and working optimally.
- Creating a door and window opening protocol to maintain sufficient air flow.
- Avoiding dust blowing equipment such as leaf blowers and diesel-powered engine equipment.
- When using pesticides, fertilisers and lime applications, ensuring there is little or no wind.
- Maintaining buildings and furnishings to a high standard reducing the need for renovation and remodelling.
- Ensuring filters in HVAC systems are properly maintained.
- Optimising lighting.
 Related articles on Designing Buildings Wiki.
- Air change rates.
- Air quality.
- BREEAM Indoor air quality plan.
- BREEAM Indoor air quality Ventilation.
- BREEAM Indoor pollutants VOCs.
- BREEAM NOx emissions.
- BS ISO 17772 - Indoor environmental quality.
- Building related illness.
- Health and wellbeing impacts of natural and artificial lighting.
- Indoor air quality.
- Lighting and health infographic.
- Sick building syndrome.
- TG10 2016 At a glance, wellbeing.
- TSI Environmental dust monitoring system.
- Use of lighting to improve health and wellbeing.
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