Disinfecting Air with UV-C vs. Filtering Air with HEPA Filters

With the ongoing pandemic continuing to affect the world we live in, more people are trying to improve the indoor air quality of their homes and businesses. HEPA filters and ultraviolet light are two common methods of air purifying. While both of them have the same goal of improving indoor air quality, the technology behind them is quite different and the type of air pollutants they can remove differ. No air purifier is perfect and without flaws. Both HEPA filters and UV-C light air purifiers come with their own set of benefits and disadvantages.

A HEPA filter is a “high-efficiency particulate air” filter made up of strands of randomly aligned synthetic fibers or glass. HEPA filters have been used by hospitals and in research environments for a long time. They are designed to trap particles that can come from pollen, pet allergens, viruses, mold and bacteria. The standard for HEPA filters is based on the (MPPS) most penetrating particle size of 0.3 microns. In order for a filter to be designated as a HEPA filter, it must meet international standards (ISO) to remove 99.95% of particles. In the United States, the standard is removal of 99.97% of particles. One important thing to remember about HEPA filters is that particles like viruses and bacteria are only trapped by the filter. If you do not replace them, then the air cleaning effectiveness goes down, and unclean filters can become a hotspot for dangerous pathogens. For this reason, it is recommended that proper PPE be used when replacing the filters. 

Traditional sanitation procedures typically do not include Air Handling Units or their accompanying ductwork. Formaldehyde used to be the most prevalent decontamination method used to attain a 6-log sporicidal kill of HEPA housings. This method was effective, but the process typically took over 12 hours and held considerable safety concerns, as formaldehyde is a carcinogen known to leave residues. When decontaminating with chlorine dioxide gas, it is often times very easy to include the ductwork and air handling system (even HEPA housings) in the scope of the project. CD gas penetrates through HEPA filters as if they are not there, and being a dry gas, it is able to navigate the bends of the ductwork system without condensing and getting "stuck."

Ultraviolet light air purifiers remove harmful pathogens from the air by actually destroying viruses and bacteria, not just capturing them. When a micro-organism is exposed to UV-C, the nuclei of the cells are altered due to photolytic processes. This process prevents further replication and causes cell death. The AirGlow is an in-duct ultraviolet light disinfection system that can be installed in any HVAC system. The AirGlow reduces and/or eliminates the growth of bacteria, mold and spores. It can also prevent the spread of airborne transmitted diseases including the flu and SARS-CoV-2 virus. As air passes by the quartz glass bulbs of the AirGlow, the travelling air is disinfected, and harmful organisms that may have been present are killed. To improve energy efficiency, the AirGlow can be positioned parallel to the cooling coils. When used on cooling coils, the Airglow is used to reduce biofilms that can accumulate on the coils. Clean coils can deliver a 30% increase in cooling capacity which in turn reduces energy consumption and costs.

HEPA filters clean the air with the use of filters located inside the air purifier. As polluted air passes through the device, HEPA filters capture many of these harmful pollutants and keep them trapped inside. HEPA housings should be decontaminated prior to filter changeout. Alternatively, ultraviolet light air purifiers use certain UV wavelengths to literally destroy airborne pathogens. Both of these devices ultimately share a common goal – clean indoor air – but one does not necessarily substitute the other.

Decontamination of HEPA Housings

HEPA housings can undergo a decontamination process for multiple reasons.  Most frequently, HEPA housings are decontaminated prior to filter changeout. They can also be decontaminated as part of a yearly routine or during construction/renovation.  HEPA housings can be on the supply or exhaust side of an HVAC system for a facility. On the supply side, they are purifying the incoming air to maintain sterility for a clean facility. On the exhaust side, they are purifying the air exhausting a facility that works with biologically hazardous organisms to prevent their escape.  

Formaldehyde used to be the most prevalent decontamination method used to attain a 6-log sporicidal kill. This method was effective, but the process typically took over 12 hours and held considerable safety concerns. Formaldehyde is a carcinogen known to leave residues behind.  Both of these attributes are concerning, especially if a HEPA housing is on the supply side of the room.

Hydrogen peroxide vapor is another decontamination method utilized for HEPA housing decontamination.  Due to adsorption issues into the HEPA filter itself, aerating HEPA housings can take considerably longer and typically lasts overnight.  Adsorption into the filter material can cause uneven concentration amounts on either side of the filter too, potentially limiting the success of the decontamination.

Chlorine dioxide has become a more optimal decontamination method, especially when considering HEPA housings.  Chlorine dioxide gas works faster, with overall cycle times between 1.5-3 hours.  Part of this is because chlorine dioxide does not leave a residue and the aeration time is shorter.  For exhaust HEPA housings, aeration is accomplished by simply turning on the exhaust blower and opening the “infeed” and “exhaust” dampers on a HEPA housing. This method aerates a HEPA housing in under a minute. For supply HEPA housings, this is accomplished by using a carbon scrubber to break down the CD gas. This method aerates a HEPA housing in under an hour.

To read more about decontaminating HEPA housings, please click here.

What is Contract Sterilization?

ClorDiSys Solutions has decades of microbial remediation expertise and offers Contract Sterilization Services to a wide variety of industries. There are two basic types. One is where we sterilize FDA regulated 510K Medical Devices in our FDA registered facility. If you’re interested in learning more about that, please come back for next week’s blog where we discuss that topic. The other is when we decontaminate your devices, equipment, supplies, and products at our facility, then ship them back to you or onward to a third party like a customer. ClorDiSys utilizes chlorine dioxide gas for sterilization instead of other commonly used gamma irradiation, ethylene oxide gas, steam, or electron beam methods. Our chlorine dioxide gas is a US EPA registered sterilant capable of killing all viruses, bacteria, fungi, and spores. It is also effective against beta lactams such as Penicillins, Cephalosporins, and Carbapenums as well as amplicons and pinworm eggs. 

When outsourcing sterilization of components, supplies, medical devices, and equipment, consider your current needs as well as plans for future growth. The outsourcing of sterilization provides convenience, efficiency, and initial cost savings (dependent on size and frequency). ClorDiSys decontaminates a wide assortment of products within the multiple decontamination chambers at our New Jersey facility to fit whatever size items required. Customers can choose to single or double wrap items in Tyvek and may include biological indicators as well. Biological Indicators (BIs) are used to challenge the efficacy of a decontamination/sterilization cycle. Turnaround time is traditionally 24 hours, with items typically being shipped back the day after they arrive. In some cases, turnaround time can be hours, with the items arriving, being treated, and shipped on the same day. Upon completion, you will be issued a Contract Decontamination Certification Sheet describing the process and showing the sterilization cycle data.

Learn more about ClorDiSys Solutions’ Contract Sterilization Services here, and contact us for a free consultation.

Case Studies: Biotech Facility's Beta-Lactam Inactivation

Recently, the ClorDiSys Decontamination Services team assisted a biotech company repurpose equipment which was previously used to manufacture a beta-lactam based product.  Repurposing equipment exposed to beta-lactams requires high-level inactivation due to the potentially life-threatening nature of beta-lactam allergies and their prevalence within society.  Having studied the inactivation of various beta-lactams using chlorine dioxide gas, our Decontamination Services team is well-equipped to handle such a task.  To read the article detailing our initial study, click here.

The laboratory in which the equipment was located had a drop ceiling.  As chlorine dioxide gas can penetrate cracks and crevices extremely well, it is able to go around and above the ceiling tiles and travel to other parts of the facility.  To mitigate the risk of leakage, the drop ceiling was covered in plastic to fully seal it off.  Inactivating the initial eight beta-lactams tested against required a dosage ten times what is required to provide a 6-log sporicidal reduction.  This meant that the use of biological indicators, our usual go-to verification method, was mostly irrelevant.  However, some biological indicators were still placed around the room in order to provide an additional data point.  In order to check for efficacy, plates were placed throughout the room with a measured inoculation of the target beta-lactam.  These plates were recovered upon completion of the chlorine dioxide gas treatment and sent to a third party laboratory for recovery testing.

The treatment itself went according to plan, with a dosage of over 7240 ppm-hrs being delivered to all surfaces within the space.  Testing came back with no recovered amounts of the target beta-lactam, showing a successful inactivation cycle had been performed.  This allowed the facility to safely repurpose the production equipment for its new use.

Microbial Contamination and Mold Remediation in the Cannabis Industry

Molds, bacteria, and yeast are present everywhere, including in the air we breathe. Controlling mold and other pathogens is essential for any operation as it is a strong threat to cannabis, potentially wreaking havoc on crops. Microbiological contamination is more common than cultivators realize. They can get tracked in from anywhere at any time, and there is always some amount of mold spores in the air pretty much everywhere you go. According to California’s Bureau of Cannabis Control testing of 10,695 legal marijuana samples from July 1 through August 29, 2018, their findings produced 1,904 failed standards. This included 403 failures due to pesticides, 99 failures for residual solvents or processing chemicals, and 114 failures due to microbial impurities such as mold, E. coli, and salmonella. Decontamination is important to ensure a quality product reaches consumers.

Chlorine dioxide gas is the optimal solution for any decontamination scenario as it is a gas as room temperature, ensuring it will come in contact with every spore on every surface, even the tiniest of cracks and crevices. Ultraviolet light disinfection is a fast, simple to use, and chemical-free method, capable of providing a 99% reduction of spores within minutes. Depending on your operation, there are different challenges to preventing or eliminating contamination.

DECONTAMINATION OF EMPTY GROW ROOMS

Chlorine Dioxide Decontamination

Gaseous chlorine dioxide is an EPA registered sterilant that can be utilized prior to any plants entering the space to ensure any pre-existing mold spores be remediated. This significantly reduces the risk of cannabis crops “catching” any new mold spores. For a complete kill of all potential organisms in the entire facility, chlorine dioxide gas is the optimal way to fill an entire space evenly and completely, decontaminating every surface, crack, or crevice with no residues or additional cleanup.

Liquid chlorine dioxide can be sprayed, wiped, or mopped onto walls and floors, environmental surfaces, growing vessels, or chambers to eliminate any existing harmful organisms. Liquid chlorine dioxide can also be dosed into irrigation water or used in hydroponic systems to eliminate any contaminants. 

Ultraviolet Light Disinfection 

Ultraviolet light (UV-C) is an easy way to achieve high-level disinfection to any exposed surface in minutes. It also eliminates odors. This chemical-free and residue-free disinfection method will help reduce mold spores, therefore minimizing future risk of exposure to the cannabis plant. This is best utilized in a completely clear space to ensure maximum exposure to the UV-C light. If there are complex shapes to the space or objects in the space, the unit may need to be repositioned or multiple units may be needed to ensure as many surfaces as possible are exposed to the disinfecting light.

DECONTAMINATION OF SEEDS

Chlorine Dioxide Decontamination

A chlorine dioxide gas treatment of seeds can be completed in a chamber prior to use to deactivate any surface bacteria, mold, or other undesirable organisms. Because CD gas is a dry, residue-free sterilant, this will ensure that the seeds are in optimal condition and no longer pose risk to a plant developing mold during the growing phase. Utilizing a Tyvek pouch will allow the gas to penetrate through, keeping the seeds sterilized until ready for use.

Seeds can soak for mere minutes in a liquid chlorine dioxide solution to eliminate any surface contaminants that may be present. The removal of such contaminants will improve the future health of the plant by diminishing the risk of mold.

Ultraviolet Light Disinfection

UV-C can be applied to seeds utilizing a tabletop disinfection chamber. While the seeds are inside, they receive 360 degrees of UV-C exposure so long as they are spread out atop quartz glass shelving, limiting overlap and shadowed areas. A 99% kill on any surface mold will result without any undue harm to the seed, destroying any surface organisms that may cause mold issues in the future during the plants’ growth.

DECONTAMINATION OF PLANTS

Chlorine Dioxide Decontamination

If mold is present or forms while drying or being stored, chlorine dioxide gas can be utilized. ClorDiSys’ EPA-registered CD gas will inactivate all microbiological contaminants without leaving a residue. This treatment can be performed either in an enclosed chamber when only a select few plants are of issue or the decontamination of an entire room if there is a widespread outbreak. Prior to decontamination, users should confirm compliance with legislation.

Ultraviolet Light Disinfection

As a fast, high-level method of disinfection without the involvement of chemicals, ultraviolet light can be utilized in numerous ways throughout the growing process. This includes the elimination of odors. It can be used on a continuous, preventive basis to avoid the spread of any mold introduced or on an as-needed basis. Buds can be treated by UV-C light to eliminate mold that may grow on the surface during the drying and curing phases. UV-C light may be emitted via a wall unit or transportable device during the drying phase in order to destroy surface contaminants. At any point, including curing, the buds may be placed inside a UV-C disinfection chamber to receive direct 360-degree exposure quickly killing spores wherever the light shines.

At ClorDiSys Solutions, we take a broad look at your operation to determine the entry points for mold and other pathogens to provide expert advice and recommendations for environmental surfaces, tools, and the plants themselves. From creating stronger workflows to recommending new disinfection equipment and procedures, we aim to be a partner for your business. Drawing upon our experiences in contamination control within many different industry types, including pharmaceutical cleanrooms and food production, we deliver solutions that have been used successfully in some of the world’s most critical environments. From seed to store, ClorDiSys can help manage your risks and produce safer products for your business.

Choose Prevention over Recall Apprehension

A recall can be extremely detrimental to a company both at the time of recall and well into the future. Avoid major consequences like production stoppages, adverse media attention, loss of consumer trust, and civil suits or federal investigations by being prepared and investing in routine preventive decontamination. Traditional sanitation methods have difficulty truly eliminating pathogens from hard-to-reach areas.  This is what allows growth niches and harborage sites to become established and create “resident strains” in your facility.  Supplementing your routine sanitation program with a high-level decontamination method can eliminate the pathogens within niches and harborage sites to provide a cleaner and safer environment.

ClorDiSys offers an all-encompassing Preventive Food Safety Program which brings together industry experts from complimentary organizations to help lead the way towards safer food manufacturing. Get an outsider’s perspective on your current Food Safety Program to gain insight and eliminate possible issues that are currently being overlooked. Through a single purchasing source, you can select from a variety of services not offered by a single organization to help find and address the gaps in your food safety program and ensure that your reputation stays in high regard among consumers.

Stop by to chat and learn more at the 20^th Annual Food Safety Summit next week or log in to our Preventive Food Safety Program webinar on May 22^nd.

Contract Sterilization Services

ClorDiSys offers Contract Sterilization Services where we can decontaminate your items, equipment, supplies, and products at our facility, then ship them back to your facility or onward to a 3rd party facility. ClorDiSys uses chlorine dioxide gas for sterilization of components instead of gamma irradiation, ethylene oxide gas, or electron beam methods. ClorDiSys’ chlorine dioxide gas is registered with the US EPA (Reg. # 80802-1) as a sterilant capable of killing all viruses, bacteria, fungi, and spores. Turnaround time is traditionally 24 hours, with items typically being shipped back the day after they arrive. In some cases, turnaround time can be hours, with the items arriving, being treated, and shipped on the same day. Upon completion, a Certification Sheet is issued describing the process and showing the sterilization cycle data.

COMMON APPLICATIONS

• Sterilization of components, instruments, or other items before entering a clean facility

• Equipment contaminated with amplicons or beta lactams

• Computers, printers, keyboards, and routers

• Electronics (RFID tags, monitoring instruments, microscopes)

• Supplies (Shoes, safety glasses, clothing, animal cages)

• Sterile products manufactured in non-sterile facility

• Medical items

• HEPA or Sterilizing Filters

• Contaminated items due to mold, pinworms, or user-site returns