Indoor air quality: The importance of achieving top marks

It is well known that outdoor air pollution has an impact on health, but indoor air pollution can also have significant and harmful effects. Good indoor air quality (IAQ) plays a major role in establishing a favourable learning environment, as well as protecting the health and supporting the productivity for both students and staff. Alan Macklin, Group Technical Director at Elta Group discusses the importance of good indoor air quality in educational buildings.

The rise of air pollutants

Over the past 40-50 years, indoor air pollution has increased due to a variety of factors, including the construction of tightly sealed buildings, the reduction of ventilation rates to save energy, the use of synthetic building materials and furnishings, and the use of chemically formulated personal products such as pesticides and cleaning supplies. Schools and colleges, alongside other educational buildings are now at increased risk of indoor air quality issues, particularly if they are in poor condition. Leaking roofs and crumbling walls can cause additional issues including contamination from lead, asbestos or dust.

Despite school staff and students spending a considerable amount of time in the confines of their buildings, a particular unknown fact is that for many, the impact of indoor pollutants can be considerably higher than those outdoors.

Achieving good indoor air quality

 Thermal comfort concerns will closely be linked to ‘poor air quality’ complaints, so it is important that temperature and humidity levels are not overlooked. Both of these are among the many factors that affect indoor contaminants.

According to Building Bulletin 101 (BB101), it is at a thousand parts per million that COlevels begin to make concentration levels drop. Similarly, temperature can also be detrimental to concentration, with people generally becoming drowsier as their core temperature starts growing warmer. Both factors therefore need to be managed effectively by a well-planned and appropriately designed ventilation system.

The consequences

 Failure to respond punctually to indoor air quality problems can lead to severe consequences. There may also be long and short-term health implications for students and staff, including coughs, headaches and allergic reactions, as well as irritation of the eyes, nose, throat and skin. More importantly in an educational setting, poor IAQ frequently leads to fatigue and lack of concentration, as outlined in study by the University of Reading in 2008 which demonstrated that the attention span of school children is significantly slower when the level of CO2 in classrooms is high.

Natural ventilation

 In existing buildings there is a trend towards using natural ventilation to improve indoor air quality, due to the perception that it cost little to run. In some baseline designs, which layout the specifications that could be applied across a wide range of educational facilities, louvres have been placed on one side of the classroom as they allow air to naturally flow through the corridors and up through an atrium.

However, the main problem with natural ventilation is that it is very dependent on the weather. For example, a building using natural ventilation in the winter is purposely allowing cold air into it, putting extra pressure on the heating system, which is likely to result in inflated energy bills. Not only that, but with outdoor air quality often hampered by factors such as transportation and grounds maintenance, this can begin to affect the quality of the air within the building.

Best practice

 When weather conditions are not conducive to natural ventilation, mechanical ventilation becomes a much more reliable option. One benefit of mechanical ventilation is that it will contain CO2 sensors that will control the fan speeds depending on the ventilation required – helping make the comfort levels within the building much easier to manage.

For those keen to go the extra mile in enhancing energy efficiency, there is a growing trend to install a heat recovery unit for each individual classroom. Put simply, a Single Room Heat Recovery Ventilator acts as both an extractor fan and a supply fan, so blows air into the room and sucks air out of it simultaneously, passing the extracted air over a heat exchanger which then transfers this energy to warm the incoming air. This ventilation method saves a lot of the heating energy especially in the winter and therefore, helps to reduce bills.

Although mechanical ventilation is not mandatory, the importance of having good indoor air quality in educational buildings speaks volumes, both in terms of health benefits and academic performance.

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