Improving Indoor Air Quality in Clinical Laboratories: Best Practices for Safety and Compliance 

Is your lab’s air breathable? You may think so, but a surprising number of indoor air quality hazards in laboratories go unnoticed until a safety issue arises—often because they are poorly understood, difficult to detect, or the blame for physical signs and symptoms is placed elsewhere. Poor lab air quality not only presents a safety risk, but can also affect equipment function and even test results. Frequent monitoring, preventive maintenance, safety training, and awareness of potential hazards are all key aspects of ensuring clean air in the clinical lab.

Key factors affecting lab air quality

Three kinds of hazards can potentially impact your lab’s air: biological, chemical, and physical.

• Biological hazards include pathogens such as bacteria or viruses, contaminants such as mold or fungi, or even allergens like pollen that have been brought in from the outdoors.
• Chemical hazards include carbon monoxide, carbon dioxide, ozone, or volatile organic compounds arising from substances used in the lab. They also include radon, which exists as an invisible and odorless gas that, at high levels, poses a radiological hazard that may increase people’s risk of cancer.
• Physical hazards typically include particulate matter, which can arise from laboratory activities, other activity (such as construction) in the area, or incidental issues such as pollution or wildfire smoke.

“All of these can contribute to lab air quality,” says Ken Roy, PhD, chief science safety compliance adviser for the National Science Teaching Association. “That’s why it’s important to ensure that the lab’s ventilation system is not only working well, but also capable of meeting the needs of the space.”

Roy refers to the National Fire Protection Organization standard NFPA 45, which establishes requirements for all laboratories using chemicals alongside additional specifications for labs in healthcare facilities. “It prohibits the recycling of lab air,” he says. “There must be fresh air coming in and used air going out.” This requirement for continuous flow is a recent change from previous guidance, which—despite mandating a minimum number of air exchanges per hour—left lab occupants vulnerable to buildups of hazardous substances.

Roy also emphasizes the importance of checking air quality in separately ventilated spaces such as fume hoods. “I had a case in which the laboratorians reported feeling unwell every time they used the fume hood. The facilities department checked the equipment sensors and said everything was working fine, so I got called in to investigate. I said, ‘Send one of your workers onto the roof to tell me if everything’s working appropriately on the ventilation unit.’ It turned out that the fan belt had broken, but because the motor was still working, the sensor was reporting no issues even though the unit actually wasn’t ventilating at all.”

Improving your lab’s air

“The first thing I recommend is hiring a consultant firm to do indoor air quality testing in the laboratory,” says Roy. “You need a specialist for this, which can be a little costly, but is well worth it.” He adds that it’s not only the air itself that should be tested. “You want to take samples from lab benches and other surfaces because contaminants there will be a result of your air quality.” Once testing is complete, the Occupational Safety and Health Administration (OSHA) requires management to share the results with employees so that everyone in the lab is aware of potential hazards.

Roy’s next priority for labs is to establish maintenance schedules to check that ventilation and filtration systems are operating within appropriate parameters. “That should happen at least once a year,” he says. “Some places should do it more often—for example, quarterly—depending on the types of tasks undertaken in the lab.” He highlights that some populations, such as people who are pregnant or have respiratory issues, are particularly vulnerable to air quality issues, so may need more frequent or in-depth checks.

“I’ve been in some labs where the filters haven’t been changed in five years,” says Roy. “They’re not filtering anything out anymore—and people wonder why they aren’t feeling well.” Air filters for laboratories should be rated MERV 13 or higher, but Roy often encounters labs whose systems are fitted with inadequate filters. Specific areas of the lab may need additional or alternative filters. For instance, tissue workstations should include permanganate filters to remove formaldehyde vapors, chemical fume hoods may need adsorbents such as carbon filters to remove contaminants, and biosafety cabinets should be fitted with HEPA or ULPA filters to ensure protection against microscopic particles and pathogens.

For fume hoods and biosafety cabinets, Roy offers additional advice. Where possible, he recommends systems that are vented to the building’s exterior rather than portable units with self-contained filtration systems. Laboratorians should be trained in the use of these systems and perform safety checks before operating them. “Before they begin, they should make sure the hood is removing air fast enough. The easiest way is to get a strip of paper, hold it between your fingers, and turn on the hood. If the paper waves into the fume hood, it’s probably moving enough air—but if it just hangs down, there may be a problem. It sounds silly, but I can’t tell you how often I find malfunctioning fume hoods using that little strip of paper.”

Roy recommends that supervisors periodically observe the equipment in use to spot and correct potential hazards, such as inadequate ventilation settings, insufficient sash closure, or too many people using or observing the equipment at once.

Finally, he emphasizes the importance of expert installation and inspection. “I’ve been called into new labs where several of the fume hoods were connected backwards,” he says. “Instead of removing the air, the systems were blowing it in users’ faces! There are many things that can go wrong, so it’s crucial to consider everything and not assume that previous steps have been done correctly.”

Good air is worth the cost

A common objection Roy encounters to his recommendations is, “Do you know how much it will cost to do these things?” His response: not as much as the potential cost of not doing them. “If any health and safety issues arise in the laboratory, management has shared liability,” Roy explains. “Under OSHA, they are responsible for maintaining a safe working environment for their employees.”

He urges lab staff to speak up when they have concerns, follow up on queries in writing, and maintain personal copies of all correspondence. 

For management, he advises meeting with employees regularly to ask about any problems or concerns in the lab—particularly with respect to health and safety. “This not only helps protect employees, but also management. It demonstrates that you’re looking for, listening to, and following up on issues.”