An in-depth survey undertaken by specialist consultancy Allergy Standards Consulting of air quality in ten office buildings in Ireland which reported complaints of ill health by occupants, has revealed that eight out of ten of the premises had inadequate levels of ventilation which caused a build up of contaminants in the air and increased ill health and absenteeism among employees.

The buildings which had an aggregate workforce of 1,500 employees and were surveyed in response to concerns of occupant ill health, showed that in the majority of cases adequate ventilation levels were not being provided either through natural ventilation or mechanical ventilation systems which was leading to a rise in carbon dioxide levels and subsequent building occupant symptoms such as headaches, nausea and fatigue.

The results also concluded that in some cases the primary source of indoor air contamination was due to biological contamination of the Heating, Ventilation and Air Conditioning (HVAC) system. These biological agents included bacteria, moulds and dust mites.

The health friendly air division of Allergy Standards Consulting provides specialist indoor environmental testing services. The programme entails taking air samples from buildings which are analysed in their Dublin laboratory and interpreted by a multidisciplinary team of doctors, occupational hygienists, occupational health advisers and scientists.

During the building survey investigations, Allergy Standards Consulting found that poor Heating, Ventilation and Air Conditioning (HVAC) system design is playing a significant part in indoor air problems. The survey found that in one building fresh air intakes were located adjacent to the building exhaust outlet and in another case, the fresh air intake was located beside a smoking area. In both these cases, contaminants were entering the building with outdoor air thus causing symptoms of ill health for building occupants.

The combination of water at the bottom of HVAC ducts, elevated induct relative humidity, together with dust to provide nutrients can provide the ideal conditions for microbial growth. Once this occurs the same HVAC system that should distribute conditioned air throughout a building then distributes these biological contaminants into the building.

A recent international systematic review of studies by a multidisciplinary panel comprising medical and engineering experts in the fields of microbiology, medicine, epidemiology, indoor air quality, and building ventilation found that there is strong and sufficient evidence to demonstrate the association between ventilation, air movements in buildings and the transmission/spread of infectious diseases such as influenza. With the HSE expecting an increase in the number of cases of swine flu towards the end of October and early in November and with 30% of the population expected to get ill over a 6 to 8 week period, employers should ensure proper ventilation of their facilities.

Ventilation plays a fundamental role in maintaining good indoor air quality and Safety, Health and Welfare at Work legislation states that sufficient fresh air must be provided in enclosed places of work.

"The health effects of biologically contaminated air are well documented and accepted by international experts. Repeated exposure to organic materials of bacterial or fungal origin is relevant to health issues such as asthma and rhinitis, mucosal complaints and allergic alveolitis. Increased exposure is also likely to result in a greater incidence of absenteeism amongst employees", said Caitriona O' Donovan, Programme Manager and Occupational Health Adviser with Allergy Standards Consulting.

"Employees have a legislated right not to be exposed to hazards in the workplace that may lead to acute or chronic, long-term health problems. So carrying out an indoor air audit should play a key role in the protection of employees' health whilst also addressing the liability risk associated with employee ill health as a result of indoor air", added O'Donovan.

Health Friendly Air Surveys undertaken by Allergy Standards Consulting include a comprehensive visual inspection of the HVAC system, measurements of ventilation rates, examination of air filters and air ducts for possible signs of contamination and sample collection for laboratory testing for signs of possible microbial contamination.