Technology developed for destroying toxic organic compounds and used by the US Department of Defence is now finding application in IVF treatment laboratories. Susan Birks reports.
As technology has advanced, the necessity to filter air has become more important. Today, many working environments require air to be free of pollutants. Dust, mould spores, pollen, dust mites, viruses and bacteria are the normal contaminants that industries are keen to keep out of products. However, some sectors find the removal of other pollutants, such as cleaning chemical components, volatile organic compounds (VOCs), automotive emissions, aldehydes, carcinogenic materials, carbon monoxide, as well as chemical air contaminants (CACs) such as sulphur and nitrogen oxides, equally important.
Nowhere is the removal of these pollutants more critical than in IVF facilities, where the quality of air in laboratories and clinical procedure rooms can have enormous effects on embryo quality, embryo survival, and hence clinical outcomes of IVF treatment.
Pollutants that can affect IVF outcomes include aerosolised pesticides, small inorganic molecules, such as nitrous oxide and sulphur dioxide, as well as heavy metals, such as lead. Many of these common pollutants can settle on work surfaces or the surfaces of tissue culture plastic ware and also dissolve in aqueous solutions of embryo culture medium.
Fresh air intakes in urban areas can contain high levels of VOCs, nitrous oxide and sulphur dioxide, as well as heavy metals, road tarmac and tarmac sealant. In addition, construction materials, MDF, PVC flooring, paints, fillers, adhesives, cleaning products and aerosol propellants are a major source of VOCs. Plastics can outgas plasticisers and mould releasing agents. Added to these are the chemical irritants lurking in the cleansers and waxes used to keep work surfaces clean, lab solvents, even perfumes, aftershaves and cosmetics and cigarette smoke.
As a result of growing evidence that air contaminants can affect IVF outcomes, cleanroom specifications for particulate and micro-organism contamination for IVF labs were introduced in the EU Tissue Directive 2006/86/EC. But removal of all of these contaminants would require very high specification air handling systems.
Based on a 2007 study, the US-based Zander Group of companies believes its air purification systems are suitable for use in an IVF facility. The study, published in the reproductive medicine journal Alpha Science,1 was designed and carried out to assess the levels of construction and product related VOC off-gassing in a newly constructed IVF laboratory with three Zand-Air 200 units installed in series in the HVAC system and to assess the performance of floor-standing zIVF-AIRe 100C air purification units in reducing ambient VOC levels in an IVF lab.
The results of the study confirmed the efficiency of the air handling units, including the photocatalytic VOC removal units in the HVAC system supplying the embryology laboratory, says Zander Group. Moreover, the results also illustrated the value of having additional in-laboratory photocatalytic ‘air polishing’ units to help eliminate locally generated VOCs.
According to Zander, the key to effective air purification is its patented photocatalytic oxidation process, where titanium dioxide in the photocatalytic chamber is exposed to specific wavelengths in the ultraviolet C radiation region (253.7nm). This makes the titanium dioxide highly reactive and thus acts as a photocatalyst ‘attacking’ the chemical bonds of organic pollutants such as solvents, alcohols, carbon monoxide and fuel oils, and converting them into benign compounds such as water and carbon dioxide.
Destroying hazardous TOCs
Based on a concept first developed in the US by Sandia Laboratory and the National Renewal Energy Laboratory and used by the US Department of Defence for destroying toxic organic compounds that are hazardous to human health and the environment, this powerful air cleaning technology is now being put to wider use.
The processes carried out by the air purification systems are outlined in the following four stages: Step one: The front position activated carbon filter (ACF) with specially formulated gas adsorption media (including zeolite and potassium permanganate) adsorbs automobile exhaust fumes, organic hydrocarbons, formaldehyde from particle boards used in construction, paints, solvents, chlorine, cleaning chemicals, VOCs, CACs and other harmful and carcinogenic agents.
Step two: A rear position HEPA filter of hospital grade and certified to have an efficiency of not less than 99.97% for 0.3µm particles, removes particles – pollen, mould, fungal spores, dust mites, viruses, and bacteria – down to 0.3µm in size.
Step three: The photocatalytic oxidation converts toxic compounds, including carbon monoxide and nitrous oxide, into benign constituents such as carbon dioxide and water. The catalyst does not wear out or lose effectiveness as a result of its action.
Step four: Ultraviolet light kills the bacteria and viruses that are too small to be filtered out by the HEPA filter. The UV lamp used in the zIVF-AIRe 100C has an output that is 99% in the 254nm wavelength range. This wavelength destroys bacteria and viruses and does not produce ozone as a result.
Zander says the air quality produced by systems using UV tech-nology combined with photocatalytic oxidation far exceeds that of other systems that depend solely on filtration or ionisation. In addition, the systems use microprocessor and computerised electronic motion sensors to monitor air quality and automatically increase the performance of the air purification system while the solid state sensor detects toxic fumes, to compensate for periods of increased human activity and unusually high chemical activity. Warning lights are also incorporated to alert staff to the presence of toxic chemicals and fumes well before they reach dangerous levels or become detectable to the human senses.
Air purification for different applications
Zander Group offers five air purification systems for different applications and spaces: The zIVF-AIRe 100C Clean Air System, suitable for IVF labs; this is effective on a variety of odours and gases, including diesel fumes, food, hospital odours, paint solvent, VOCs and CACs, acid gases such as hydrogen sulphide, sulphur dioxide and hydrogen chloride. It is also formulated to absorb very light gases such as ammonia, formaldehyde and other aldehydes. The ZAND-AIR 100P Air Purification for biochemical, histology and pathology laboratories; this system can play a major part in protecting laboratory staff from harmful compounds such as zylene, toluene, benzene and other carcinogenic agents. The ZAND-AIR 200 for existing HVAC systems and new constructions; this system is designed to be incorporated into new or existing constructions and renovations to protect people in lab environments against indoor air pollutants. It can convert VOCs and CACs, viruses and bacteria into H2O and CO2, and harmless small particles, all within the capacity of existing HEPA filters, activated carbon filters, and blowers of the existing HVAC equipment. The ZAND-AIR PCOC3 combines in one frame three chambers of the model ZAND-AIR 200, saving space in HVAC units and assisting in airtight installations in HVAC and ductwork with VAV units. The ZAND-AIR 20C CLEAN AIR filtration and purification system is for the office.
Contact Zander Scientific 755 8th Court, suite #4 POB 650790 Vero Beach Florida, Fl 32965-0790, USA T +1 772 569 5955 www.zandair.com
