The inside information on indoor air quality

With issues surrounding outdoor air quality grabbing most of the headlines, indoor air quality is often left out of the discussion altogether. However, the momentum is now starting to shift as a multitude of studies demonstrate clear links between indoor air quality and productivity and well-being in the workplace. Russell Beattie, at the Federation of Environmental Trade Associations, looks at the impact ventilation systems have on indoor air quality and explains why it is time to introduce a clearly defined assessment method

Air pollution is now recognised as a worldwide issue and measures are being put in place by government and the World Health Organisation (WHO) in a sustained effort to clean up the air in our towns and cities. The UK government recently announced new measures to restrict the use of wood burners and fires as part of its clean air strategy – legislation that is aiming to help cut the cost of air pollution to our society by £1 billion a year by 2020 and by £2.5 billion a year by 2030.

While this renewed determination to tackle the chief culprits of air pollution is to be welcomed, more needs to be done to drag indoor air quality into the picture. Where the UK government is concerned, indoor air quality exists in a state of limbo, with no single government department claiming overall responsibility and no official guidelines issued.

The Federation of Environmental Trade Associations (FETA) recently made direct contact with the Ministry for Housing, Communities & Local Government (MHCLG) in an attempt to determine where responsibility for indoor air quality ultimately rests. The MHCLG’s response confirmed that there is no single departmental lead and a number of different government departments and organisations hold a stake and work together to collaborate on the issue – including MHCLG, Public Health England, the Department for Business, Energy & Industrial Strategy (BEIS), the Department for Environment, Food & Rural Affairs (DEFRA), Department for Transport (DfT) and the Health and Safety Executive. The Department for Education also play a role in relation to ventilation in schools, adding yet further complexity to the picture.

Invisible threat
Most of us spend a staggering 80-90 per cent of our lives indoors and the common desire to reduce CO2 emissions and build low carbon buildings means that many homes and commercial properties are becoming increasingly air-tight. Poor indoor air quality can be attributed to a diverse range of sources, but the situation is often made worse by pollutants used in building materials, internal furnishings and cleaning products, or by actions such as cooking or painting. Unwanted biological invaders such as dust mites, mould and suspended allergens can also impact upon air quality and even pollutants from external sources can ingress through windows, doors or other openings.

Pollutants emitted from common office equipment, carpets, paint, aerosols etc. are known as volatile organic compounds (VOCs) and concentration levels are commonly much higher in buildings where ventilation is limited. New buildings in particular register higher readings as the new materials all generate particles at the same time.

Humidity levels can also have a direct bearing on the health and well-being of building occupants and optimum levels are generally between 30-70 per cent relative humidity. These levels can be maintained through the introduction of a carefully considered and professionally installed ventilation system with the ability to deliver cleaner air from outdoors or filtered, recirculated air when needed.

Design, commissioning and maintenance
Building performance and energy usage is now a key part of the design process but indoor air quality is rarely afforded more than a fleeting thought when planning a new build. Decisions based around heating, cooling and ventilation can be vital in ensuring good indoor air quality but so too can choices concerning location, the orientation of the building and the positioning of air intakes. Following on from design considerations, proper installation and assembly of systems is just as important. Get the initial setup wrong and it may be difficult to make the necessary changes without causing widespread disruption to business operations.

Routine maintenance can also help to ensure high standards in older properties. Regular HVAC checks and cleaning of duct systems can reduce the risk of a particulate build up – a common problem if the system hasn’t been in use and has been left idle for weeks or even months. Without a scheduled maintenance plan in place, accumulated dirt and dust particles are quickly circulated around the building when the HVAC system is restarted.

Sick building syndrome
Without adequate ventilation, stale air can circulate for prolonged periods and in large buildings simply opening a few windows isn’t enough to sufficiently improve air flow. Offices or buildings with high occupancy levels are particular susceptible to this sort of build-up and the term ‘sick building syndrome’ was coined many years ago to describe common symptoms such as headaches, dry or itchy skin and respiratory problems.

CO2 levels are measured in parts per million (ppm) with the recommended indoor level capped at around 600 ppm. Anything beyond 1,000 can lead to drowsiness and the risk of more serious effects is heightened significantly when levels pass the 2,500 mark. A study by the National Institute of Environmental Health Sciences (NIEHS) suggests that CO2 increases from 1,000 ppm to 2,500 ppm result in a drop in employee performance of around 35 per cent during basic activities. When employees are using information to complete a task this performance reduction is even starker at an average of 60 per cent. When asked to use initiative during a task, the increase to 2,500 ppm brings about a massive 91 per cent drop in performance.

In more recent times, the causes and effects of sick building syndrome have been incorporated into studies pertaining to overall ‘well-being’ within the workplace and although this has given rise to whole new industry addressing our physical and mental health at work, more needs to be done to determine the impact HVAC systems on indoor air quality.

A clear metric
Regular cleaning and inspection of ventilation systems and air conditioning filters may be a quick and relatively straightforward way to make an instant impact but all available evidence suggests that a standard air quality metric should be introduced in order to highlight unacceptable pollutant levels and accurately measure the influence of different ventilation systems.

There may be an assumption that complying with building regulations naturally means that indoor air quality levels will be roughly comparable between systems and generally up to scratch. In reality, ventilation systems that comply with regulations can differ wildly in terms of impact on indoor air quality. Indeed, ventilation rates laid out in standards around the globe can differ by up to four times.

In the UK, Approved Document F contains recommended performance levels for indoor air quality and further guidance can be found in The Health and Safety at Work Act 1974 and the Health and Safety at Work Regulations 1992, which outline general duties in providing a working environment that is both safe and without risk to health.

The 1974 Act does state that workplaces must be adequately ventilated and should draw fresh clean air from an external source in order to achieve this. It is also noted that the ventilation system should remove and dilute warm, humid air and provide air movement, to create a sense of freshness without causing a draught. Unfortunately, this is not enough in terms of accurately assessing performance in ventilation systems.

Addressing this issue, The European Ventilation Industry Association (EVIA), in conjunction with seven other European Associations, has been working hard to develop an assessment method for determining the impact ventilation systems have on IAQ – an initiative that has FETA’s full support. It is hoped that this will eventually lead to the introduction of a recognised metric that stipulates methods of calculation and identifies device characteristics, calibration intervals, tolerances and analyst competences. This valuable tool would help to evaluate the true impact of ventilation systems and go a long way in helping to formally recognise and address issues surrounding indoor air quality.