For years office workers have suffered unexplained headaches, asthma, allergy-like symptoms and other respiratory distress now recognized as “sick building syndrome” (SBS). Although there have been many reports on SBS, (there is no precise definition) cost estimates range to billions in absenteeism and lowered productivity. Currently, about 15 million workers in the US are affected to some degree by SBS and could be eligible for health benefits. SBS is caused by “poor” indoor air quality from energy-efficient, airtight buildings and the resulting concentration of airborne contaminants. Given that more than 70% of the workforce in North America and Europe work in office environments, this problem is significant. As well, “buddy sickness” (i.e., caused by airborne germs which can infect people in the office) contributes to absenteeism and reduced productivity (how many times have you gone to work when you have a cold or flu, only to spread it to your co-workers?).


 Recent Studies

Ultraviolet germicidal irradiation (UVGI) has long been used to sterilize hospital instruments and sensitive areas, and recently used by Novapure for treating air in offices. The benefits of this technology in mitigating SBS have now been quantified by a very recent study conducted by the Montreal Chest Institute at McGill University (results are published in the British medical journal, The Lancet). The “double blind” study found that installation of UVGI air purification equipment resulted a *20 percent overall reduction in all symptoms* for some workers; a *40 percent reduction in respiratory symptoms* and a *30 percent reduction in mucous problems*. The benefits were greatest for workers with allergies and for those who had never smoked.


 Causes of SBS

To better understand why UVGI is so effective, it is helpful to understand the causes of SBS. High levels of pathogens and allergens (primarily microbes) in offices and in HVAC systems are important contributors to SBS. In modern HVAC systems cooling coils (moist with condensation) are ideal breeding grounds for molds and bacteria. Molds and bacteria thrive in the wet environment of the coils and can form “biofilms” (a slimy growth) on the coil surface. Covered with biofilm, the “dirty coils” are less efficient so that the HVAC system requires more energy to condition the air while circulating aerosolized (airborne) pathogens/allergens. In studies conducted by major HVAC manufacturers, clean coils result in 30% to 40% energy costs savings compared to dirty coils. More importantly, the mold spores and bacteria become aerosolized or airborne, and can be circulated in the air supplied to the offices. Because most of the air in office buildings is recirculated, the airborne contaminants are concentrated and workers experience symptoms of SBS. Other contaminants that affect health are volatile organic compounds (VOCs). These are the chemicals, vapors, or fumes released by building materials, coatings, solvents, or cleaning products. In our testing of indoor air, we have found that office furniture, shelving and items made from medium density fiberboard (MDF) or oriented strand board (OSB) are the worst culprits for releasing VOCs into the air; however, new carpeting, wall coverings, glues and paints can also release VOCs.


 The UVGI Solution

A properly designed UVGI system can reduce the level of airborne contaminants and reduce building energy costs. In summary, UVGI systems are installed t

a. Irradiate the cooling coils. Germicidal ultraviolet light kills molds, bacteria and viruses and prevents the growth of biofilm on the coil surface. This increases the energy efficiency of the and dramatically reduces airborne contaminants (up to 99% on irradiated surfaces, according to the latest McGill study).

b. Treat microbials in the air stream. UVGI inactivates (so they cannot infect) airborne viruses, bacteria and molds. As air is recirculated through the HVAC system, UVGI continuously and progressively treats the air to reduce microbial contaminants and the buddy sickness that can result.

c. Decompose VOCs in the air stream. In Novapure air treatment systems, photocatalytic (PCO) reactors further reduce airborne microbials /and/ VOCs. PCO reactors, inexpensive but highly effective, operate without consuming power and without creating heat. Ultraviolet light activates the PCO reactor surface destroying any microbial or chemical contaminant making contact. This feature makes Novapure’s air treatment system unique in the air treatment industry. UVGI alone does not destroy VOCs (unless the ultraviolet lamps produce toxic ozone, a very undesirable contaminant in occupied space).

**


 Expected Benefits

In summary, the potential economic and health benefits of well-designed UVGI installations are:

   * *A 20% reduction in sickness and a 40% reduction in respiratory
     problems (i.e., translates into savings due to lowered absenteeism
     and increased productivity) *
   * *30% to 40% energy savings from cooling coils operating
     efficiently to their original specs, due to no biofilm growth *
   * *reduced maintenance costs to keep the cooling coils clean*

Design Considerations

To efficiently size UVGI systems for commercial/institutional applications, Novapure has developed sophisticated computer models which consider coil area, airflow, duct size, UV wattage, system geometry, amongst other variables.

Costs for installed UVGI systems can vary widely, depending on the building and the HVAC system. Acquisition of UVGI equipment can be structured as an eligible service expense under a triple net lease or as a depreciable capital cost. The expense is more than offset by energy cost savings and the economic benefits of reduced absenteeism and increased productivity of healthy workers. Excellent indoor air quality also makes a building more attractive to existing and future tenants!