Indoor Air Quality

Poor indoor air quality can lead to the number of people who suffer from asthma to increase by up to 80% over the next 35 years if the current regulations and not changed.

A report released in September ‘The Future of Indoor Air Quality in UK Homes’ by Professor Hazim Awbi on behalf of Beama also warns that Volatile Organic Compounds (VOC’s) may rise 60% above what the World Health Organisation (WHO) recommended limits for any given 24 hour period.

Most individuals spend 90% of their time indoors and therefore exposed to the indoor environment. Contaminants within the indoor environment are more than 1000 times more likely to be inhaled than outdoor air, and can be 10 times more polluted than outside air.

In 2004, a study showed that around 15% of people have asthma, and the UK has the highest prevalence of asthma in the world (Howiesons, 2005).

Existing building regulations enforce improved air-tightness on all new homes, however building regulations have not taken into consideration the adverse impact of improved air-tightness and increased energy efficiency on indoor air quality and the health of occupants.

The UK Government Energy Targets 

The UK government is committed to an 80% reduction in carbon emissions by 2050. 46% of present UK consumption is in existing buildings and of this 30% in domestic dwellings and 16% in non-domestic buildings.

The report also details that in order to meet emission targets would likely to impact on indoor pollution levels up to 2050 if there is no additional intervention over and above the current requirements. Further reducing the natural ventilation within buildings, however additional measures need to be implemented to avoid problems with poor air changes within properties.

Inadequate ventilation within modern energy efficient homes and offices is also associated with a higher airborne infectious disease transmission as well as the accumulation of indoor pollutants and dampness which are factors in the development of allergies and asthma.

Most homes and places of work without adequate provision of mechanical or natural ventilation systems in place can mean the air changes can fall below the minimum recommended 0.5 air changes per hour (ac/H) necessary to avoid condensation.

Health Implications 

The link between poor indoor air and health is well documented, with links to a range of health problems including asthma & allergy symptoms, lung cancer, chronic obstruction pulmonary disease, airborne respiratory infections and cardiovascular disease.

High levels of carbon dioxide in offices and classrooms could can effect concentration and may be the reason so many doze off in meetings. Typical outdoor concentrations of CO² are around 380 parts per million (ppm), indoor concentrations can easily reach several thousand ppm where no ventilation system or poor ventilation systems are in place.

There is a link between high levels of carbon dioxide present in classrooms and offices and a decline in work performance and concertation.

Conclusions

• New build and existing properties would benefit from improved mechanical ventilation systems which may comprise of air handling & extract ventilation.

• Heat recovery units which operate by recovery the heat from the exhaust air and transferring the heat energy to the fresh supply air. Heat recovery or HRV’s can recover up to 85% of the heat from the extract air stream.

• Maintenance of such air handling unit and heat recovery units can often be overlooked or simply forgotten about, as mostly these are installed within roof voids or out of sight.

• Most units incorporate synthetic panel filters and bag filters which should be replaced frequently depending on the application of the system, but usually every 6 months for general office areas.

• Productivity can also be adversely affected by a lack or air changes within offices where excess CO² is allowed to accumulate.

• Best compromise between good indoor air quality and optimal utilisation of energy efficiency

The air we breathe is critical to our health, comfort and productivity. 

(Image courtesy of Arvind Baraman at FreeDigitalPhotos.net)