Fungal and bacterial microorganisms are ubiquitous elements of the flora that an individual is exposed to on a daily basis. At Health Friendly Air (HFA) we have acquired significant experience in addressing the occurrence of these issues in businesses and homes and as a result are well placed to detect them and subsequently advise on measures which need to be addressed. This article considers these in the context of other indoor environmental factors and how seasonal changes in building maintenance have been shown to affect Indoor Air Quality (IAQ).
The term “Sick Building Syndrome” was initially described as “a building in which complaints of ill health are more common than might reasonably be expected”. The manifestation of medical conditions associated with poor indoor air quality have been shown to include eye, ear, nose or throat irritation, wheeze and tightness of the chest, headaches, nose bleeds, skin sensitisation and general lethargy as well as exacerbation of asthmatic conditions. (Finnegan et al., 1984). In addressing the issue of indoor air quality (IAQ) experience has shown us that the multifaceted nature of the indoor environment results in many variables which may result in conditions that favour the development and concentration of air pollutants. Humans by their nature shed skin, exhale carbon dioxide, are a source of volatile organic compounds as well as being a harbour for pathogens and allergens. These factors and the need to reduce them have been shown to play a major influence on the perception of IAQ.
In recent years the need to find a balance between IAQ and sustainable building development has been affected by the greater emphasis placed on improved energy conservation in new and renovated buildings. These changes are necessary and have their economic benefits over time but are frequently at the expense of the preservation of adequate ventilation resulting in the development of conditions that allow for the proliferation and persistence of advanced microbial colonisation. In turn, changes to optimal physical, thermal and gaseous conditions can seriously hinder comfort and productivity with reduced concentration, lethargy and reduction in the perception of IAQ. Many of the materials used in building interiors contain cellulose. Cellulose is a ubiquitous polysaccharide and is the primary constituent of the plant cell wall. As moulds often occur as saprophytes, (acquire nutrients from decaying vegetation including plants), complex sugars such cellulose are broken down to simpler carbohydrates which can be absorbed. Therefore it is an excellent substrate for fungal growth, with a body of evidence demonstrating its presence in building materials such as tiles and joinery favour conditions for fungal growth and proliferation (Karunasena et al., 2001). In nature fungal species often function in the process of decomposition and cycling of nutrients therefore their visible presence in the indoor environment is of particular concern in the a maintenance of structural integrity. Certain mold genera including Aspergillus, Penicillium, Stachybotrys, Cladosporidium, Mucor and Alternaria as well as species from the phylum Basidiomycota have been heavily implicated in fungal infection and sensitisation reactions acquired in the indoor environment. The ability of these fungi to colonise and grow on the numerous materials and textiles used in modern building construction while being able to withstand significant variation in temperature, moisture and pH represents a significant issue for asthmatics and some with underlying medical conditions. Individuals who suffer from asthmatic fungal sensitisation are particularly at risk of developing allergic and asthmatic reactions thus greatly reducing their quality of life. In cases where individuals are immunosuppressed or have existing pulmonary issues such as emphysema, tuberculosis or cystic fibrosis this becomes a greater risk with mortality rates from invasive infections notably high. It follows that the economic impact owing to the cost of healthcare to individuals and the loss of comfort and productivity as a result of indoor mold growth means that there is an acute need to prevent and eliminate fungal colonisation and persistence in the indoor environment.
The natural ventilation of office and industrial buildings generally reduces during winter months as a result of the need retain heat in colder weather. As a result cumulative effect of increased humidity due to inadequate ventilation coupled the seasonal increase in airborne mould means that the incidence of IAQ issues increases during the autumn and winter. Modern office buildings rely in many cases upon an effective HVAC system for the purpose of supplying adequate ventilation and correct thermal regulation depending on the time of the year and the associated climate. While recognising the need to maintain thermal comfort, issues relating to the recirculation and temperature adjustment can result in suboptimal conditions for employee productivity. For example low relative humidity (< 40%) can lead to drying of the mucous membranes which can cause discomfort while increased carbon dioxide from recirculation of office air resulting from exhalation has been shown to result in a dimunition of concentration over time. Additionally HVAC systems have been shown to be an ideal area for the development of microbial proliferation when not properly maintained. There is a high level of regard given to the risks associated with Legionella contamination in HVAC units which is entirely merited given its significance as a pathogen in Legionnaires disease and Pontiac fever. It must be stressed however that incorrect maintenance of HVAC units and associated ductwork have also been shown to result in higher levels of other pathogenic bacteria and fungal microorganisms. Given the recirculation of air during operation, a contaminated HVAC unit or associated ductwork can have a marked influence on IAQ as we have observed a direct correlation between duct contamination and airborne microbial counts.
Irish legislation states that employers have a general duty to employees to ensure the safety health and welfare at work of his or her employees (Part 2 Chapter 1 of the Safety, Health and Welfare at Work 2005). In addition section 2, schedule 2 of the Safety, Health and Welfare at Work (General Application) Regulations 2007 (S.I. No. 299 of 2007) states that “Steps should be taken to ensure that there is sufficient fresh air in enclosed places of work, having regard to the working methods used and the physical demands placed on the employees”. It is therefore evident that an indoor air quality audit should play a key role in the protection of employee health. As well as the potential threat of litigation there is the potential financial stress implied by days lost to employee sick days. As a result it is evident that correct monitoring of air through a regular review of airborne microbiological content as well as physical and chemical parameters which are most likely to affect occupant health should be an integral part of employer health and safety statements.
With this in mind the Health Friendly Air division of airmid healthgroup was formed in 2009 to enable clients identify and address current and potential IAQ problems. Health Friendly Air combines expertise from occupational hygienists, scientists and medical professionals to offer a comprehensive service which is valued by employers, employees and homeowners. Our ability to design the most appropriate quality driven tests and procedures for indoor spaces as diverse as homes and office spaces is unmatched in our field. Furthermore, our commitment to providing a comprehensive service means that the homeowners, health and safety officers and office managers can have the peace of mind that they are being equipped with the best knowledge as to the status of their IAQ.
References
Finnegan, M.J., Pickering, C.A.C. and P.S. Burge, (1984). The sick building syndrome: prevalence studies. British Medical Journal, 289: 1573 – 1575.
Karunasena, E., Markham, N., Brasel, T., Cooley, J.D. and D.C Straus, (2001). Evaluation of fungal growth on cellulose-containing and inorganic ceiling tile. Mycopathologia 150: 91 – 95.