Good air quality in modern buildings is important in preventing the damaging effects that Sick Building Syndrome can have on a workforce's health and productivity.  Simon Skentelbery reports on some of the problems which can affect the working environment.

Indoor air quality has a major influence on the heath and well being of office based workers. Poor air quality has been linked to problems of Sick Building Syndrome (SBS) which is known to reduce productivity in the workplace. SBS is a term that describes a set of symptoms associated with a person’s home or place of work. The World Health Organisation (WHO) has recognised SBS as a medical phenomenon since the early 1980s; the WHO also estimated that 30% of all SBS cases could be linked to new-build or extensively refurbished buildings.

SBS and Symptoms Caused by Poor Indoor Air Quality

Typical SBS symptoms include sore eyes, nose and throat, skin irritation, regular bouts of general illness, extreme lethargy and poor concentration. Extreme cases can lead to multiple chemical sensitivities (MCS), hypersensitivity (undesirable and extreme reactions created by the body’s immune system) and neurotoxicity (damage to the nervous system by the presence of chemicals). Although many of these symptoms cease quickly after the individual leaves the problem location, in some cases damage can be longer lasting or permanent sensitisation may have occurred.

However, SBS tends to be at the extreme end of the spectrum and ignores the fact that many occupants, especially in the workplace, feel the effects of poorly managed indoor air quality (IAQ) every day without raising the issue with their employers. Most office-based workers have felt the effects of below-par IAQ at different times of the year in their workplace. Symptoms are typically nothing more serious than a general malaise and poor well being, but these minor problems can develop over time and become a SBS case, possibly across the entire workplace.

The impact of SBS and general poor IAQ is wide ranging, from barely detectable reduction in efficiency amongst individuals to the widespread loss of well trained and valuable employees due to long term or even permanent sickness.

It is often difficult to tackle SBS and poor IAQ effectively. There may be no pattern to the symptoms which leads management to assume there are no connection to the illnesses and no air quality problem to solve. Getting to the bottom of the issue is often further complicated by people showing ‘sympathetic symptoms’ between each other or through the presence of a ‘normal bug doing the rounds’, both of which will mask a possible IAQ problem.

Sources of Poor Indoor Air Quality

Good indoor air quality depends upon the effective control of various pollutants that may be present in the building. These include:

• Volatile organic chemicals (VOCs) such as formaldehyde
• Gases such as nitrogen dioxide (NO2) and carbon monoxide (CO) from combustion, ozone (O3) from electrical equipment
• Particulate matter and fibres such as PM10 and PM2.5 from vehicle movements, or building materials in poor condition
• Biological particles including bacteria, fungi, pollen and mites

The impact of these pollutants is often worsened by the synergistic effects caused by a number of other sub-optimal conditions present in the building including:

• Poor lighting (low or high) and lack of natural light
• Lack of fresh air dilution into the building
• Noise and poor acoustics
• High temperature
• Very low or high humidity
• Poor ergonomics

Sources of such pollutants can be from the outside environment or from within the workplace itself. External sources are characterised typically by pollutants such nitrogen dioxide, sulphur dioxide, soot and particulate brought into the building from open windows, ventilation systems and air conditioning intakes positioned near busy roads or through offices placed in heavily industrialised locations.

Often pollutants responsible for poor comfort and well being in offices are as a result of internal sources such as:

• Soft furnishings and recently applied decorative coatings (VOCs and formaldehyde)
• Cleaning products (VOCs and various other chemicals)
• Electronics (ozone, chemicals released due to plastics overheating)
• Toiletries (VOCs)
• Tobacco smoke (though illegal in the UK, smoking areas are often poorly situated)
• Office over population (carbon dioxide and biological particles)
• Poor cleanliness and housekeeping (dust mites)

Approved Document F of Building Regulations 2006 gives specific performance criteria for controlling many of these air pollutants.

Basic rules of thumb for good IAQ:

In addition to minimising the presence of pollutants, the following rules of thumb should always be followed in an office environment if IAQ problems are to be kept under control:

• Carbon dioxide – measured concentrations exceeding 2000ppm is a clear indicator of potential problems and poor ventilation
• Temperature – 19˚C is optimal for an office environment, anything above 22˚C can affect the overall comfort of the office, can increase the presence of some volatile pollutants and will also increase the impact of any pollutants present
• Humidity –  30 to 70% is the ideal; >70% and the workplace can become an ideal environment for moulds and other biological contaminants, <30% and the air becomes uncomfortable for people susceptible to dry eyes and throats
• Ventilation – ventilation will ideally provide 6-10 air changes per hour in an office environment

Other issues that should be considered include:

• Ensuring sufficient light is available - 500 lumens is a good guide for normal office-based work and the provision of natural light can help mitigate other problems
• Minimising background noise - BS8233 gives a recommendation of 45-50dB LAeq for open plan offices, although the acoustics of specific noise can be a contributory factor in SBS cases

Diagnosing the Issue

An IAQ issue is generally highlighted in response to a complaint or series of complaints. The diagnosis process starts with a walk through of the location to determine which factors influence the IAQ problem. Those factors can be broken down into:

• Occupants and how they are being affected
• The ventilation and heating/air conditioning system (HVAC) and its operation
• Pollutant sources and how they impact on the IAQ of the location(s)

The walk through may identify a clear problem but at the very least it will give some indicators that may help target more detailed investigations. Completing an initial questionnaire with simple logical questions can help build a pattern in terms of problem locations or any linking symptoms and the times and regularity of these symptoms.

Obtaining up to date and detailed maps and plans of the building and HVAC system as this will help bring sense to any complaint patterns and help lead to a specific source such as an air supply outlet. Obvious problems such as dirty vents or air conditioning systems that have not been maintained and balanced should be reasonably obvious.

Commissioning an External Specialist to Determine the Issue

These findings may be sufficient to target improvements that can be made immediately leading to a successful conclusion to the problem. However in some cases there will be situations where an external specialist such as an Occupational Hygienist needs to be brought in. Such situations include:

• Efforts made have not solved the problem; or that the in-house assessment suggests that further data is required to target possible solutions
• An independent survey would be better received by the workforce
• Initial findings indicate a serious issue that needs to be solved quickly
• The in-house investigation shows that more complex issues may exist

The Hygienist should be able to demonstrate extensive experience in IAQ issues. Time honoured experience is crucial in investigating these problems. They should ask pertinent questions and start to build a picture of the problem very early on – how big is the building, what problems have been noted, what type of building is it, how old is the building and where is it located?

IAQ issues can take time to work through and require a range of measurements to be completed, so a fixed cost is not always possible. However, the Hygienist should be able to provide a daily rate and a likely timescale as a minimum – a lot of work can be completed in one day but IAQ work can require more than one avenue of investigation.

Mitigation

Once the problem is fully understood, mitigation generally falls into four main categories:

• Source control – cost effective; examples include replacing pollutant sources or managing the environment to prevent pollutants from being generated (such as maintaining humidity levels to prevent the build up of airborne spores)
• Correct ventilation – improving dilution using clean air or improve extraction of specific problem locations
• Air cleaning – potentially expensive and should be used in conjunction with one or more of the above techniques; filtration (particles) or adsorption (VOCs) are typical air cleaning methods
• Exposure control – remove susceptible individuals from problem areas; this is the least preferable option as it is not often practicable and does not deal with the source of the problem.

Nearly all office-based IAQ issues relate to incorrect ventilation, poor temperature control and high or low humidity. Installing trickle vents on windows or just ensuring that fresh air is allowed to ventilate the building can help mitigate many IAQ problems, alongside correct HVAC maintenance.

The average person spends a considerable period of time working within offices yet ensuring the quality of the air quality within these locations is often forgotten - decent air quality is as integral to an effective and healthy workplace as providing a comfortable chair or desk.

Simon Skentelbery
General Manager Occupational Hygiene
ALcontrol On Site Services