Volatile Organic Compounds
Volatile organic compounds are another enemy of IVF labs. VOCs are hydrocarbon based compounds that are found in fuel, solvents, adhesives, and other compounds. Epoxy glue is a prime example of a substance that releases significant amounts of VOCs.
Other VOCs are isopropanol (aka Isopropyl Alcohol,) benzene, hexane, formaldehyde, vinyl chloride, and many others.
Where do VOCs come from in an IVF lab?
Any new construction is going to release VOCs from the paint and construction materials. Also, all furniture made today is going to have some amount of particle board, which is 10% formaldehyde resin by weight. Formaldehyde resin off-gasses for over 20 years. Yes, that is 20 years that it will be giving off trace amounts of FA.
I think it is somewhat misguided that many labs undergo a "burn-in" period where they heat the room up to 120 degrees for a couple days to supposedly "burn off" all the VOCs in their building materials. This may work for some trace VOCs back in the day when construction used mostly natural materials. In this day when everything is laminate, it is not likely to have the impact many people think.
Think you don't have VOC producing material in your lab?
Did you know that many stainless steel cabinet manufacturers use a 3/4 inch thick piece of particle board under the steel to give rigidity to their countertops?
VOCs can also occur in medical gases, such as CO2 and nitrogen. It is important to use inline VOC filters for your medical gasses to prevent these fumes from entering your incubators.
In the lab, new incubators frequently have VOCs being released, as they were put together in a factory and had VOC releasing materials used during their construction. It is recommended to off-gas an incubator for 3 to 5 months prior to putting it into use.
Unexpected sources of VOCs are commonly found in IVF labs. These can include cleaning agents, perfumes, cabinetry, grease on the wheels of equipment, and sources in HVAC equipment.
How to Measure VOCs
VOCs are typically measured in parts per million (ppm.) They can also be reported in parts per billion (ppb.) For IVF, you absolutely want your counts below 0.5 ppm. Ideally, they should be below 0.2 ppm total VOCs and preferably zero.
We use a VOC meter that is extremely senitive and can measure VOCs down to zero parts per billion. It is not enough to just have the instrument. Like many things in medicine, it is a tool that requires a skilled user to know how to interpret the results.
Thousands of dollars can be spent trying to treat a VOC problem that does not actually exist, while pregnancy rates can suffer if a VOC problem is not accurately detected and quantified.
When setting up an IVF lab, it is important to accurately measure VOCs in the building, in the lab, and in the incubators. These should not only be measured as part of the initial set-up, but also measured on an ongoing basis.
VOCs and IVF
Cohen et al wrote the seminal paper on VOCs and IVF in 1997. They found that after moving their IVF lab, their pregnancy rates dropped significantly and it was due to high levels of VOCs. They also had a drop in their rates when their neighbor in the building replaced their vinyl floor. This used large amounts of adhesive (VOC source) which contaminated their IVF lab.
VOCs levels at high levels (over 1 ppm) will be directly toxic to embryos and you will see poor mouse test results and very poor human embryo development, probably not even making it to blastocyst stage.
VOC levels in the 0.5 ppm range will typically allow for acceptably blastocyst development and reasonable pregnancy rates, but a high percentage of miscarriages.
VOCs can occur on a continual basis, such as chronic off-gassing from a piece of furniture made of particle board. Or they can occur in pulses, such as from a cleaning agent used to clean ultrasound probes or the floor. If this agent is used at a time the incubators are being opened, these fumes will enter the culture media and have a negative effect on embryo development.
More Reading.
Cohen Article (click the manual download button once on the cambridge site.)
How to Reduce VOCs
Treating VOCs is similar to treating particles. You have to either prevent them from entering the lab in the first place, or remove them faster than they are coming in. Both Coda and IQ-Air make filters that will sit in the lab and remove VOCs that are in the lab. The important thing is to be able to measure your results and be certain that they are doing an adequate job.
The other way is to have an adequate HVAC system with carbon based media that filters the VOCs prior to entering the lab. This is the better option, but may not be possible in some buildings, or be prohibitively expensive. There are a number of manufacturers that make housings that can be fitted to your HVAC plenum to filter VOCs as well as particles. These units must be properly sized and maintained to achieve the results you desire.
Photocatalytic oxidation units - These units use ultraviolet light to excite a titanium dioxide screen which supposedly breaks down VOCs into CO2 and water. Zander and Ultrasun technologies are two manufacturers of these units. I am not a fan of these units, as evidence exists which shows these units break down larger VOCs into smaller VOCs. In addition, these units also generate high levels of free radicals which are not good for IVF. These units are sold as a cheap alternative to media-based systems. Unfortunately, they do not do the job.