Las Vegas Review-Journal

Six questions to ask about COVID and air quality at work

- By Tara Parker-pope

Whether you’ve already returned to your workplace or will be heading back to the office eventually, it’s a good idea to ask what steps your employer has taken to improve indoor air quality.

The more time we spend indoors with other people, the more likely we are to breathe each other’s exhaled air — and germs. The vast majority of scientists now agree that the coronaviru­s is airborne, and infectious droplets can linger in the air, float around the room or build up in spaces with poor air flow, like conference rooms. Early in the pandemic, a coronaviru­s outbreak on the 11th floor of an office building in South Korea showed how just one infectious person can increase the risk for everyone in a workplace. Out of 216 people on the floor, 94 were infected. Most of the infected worked in rows of desks grouped on one side of the office.

Even before COVID-19, it was clear that indoor air quality could affect workers’ health. A well-known Harvard study of more than 3,000 workers showed that sick leave increased by 53% among employees in poorly ventilated areas.

While vaccinatio­n requiremen­ts and masking remain a first line of defense against COVID, ventilatio­n improvemen­ts in schools and workplaces are essential to stopping the spread of the coronaviru­s, said Dr. Ashish Jha, dean of the Brown University School of Public Health.

“Improving indoor air quality can be a really powerful tool,” Jha said.

In addition to asking questions about ventilatio­n, you should ask about vaccinatio­n policies, staggered workdays to reduce capacity, COVID testing plans, mask requiremen­ts and how the building is monitoring outside workers, like delivery people and cleaning crews.

And while some of the technical details around air quality can be confusing, you don’t have to be a ventilatio­n expert to figure out what extra precaution­s your employer has taken to keep you safer during the pandemic. Asking about efforts to improve indoor air quality can help you make decisions about how much time you might spend there, whether to mask up or buy a portable air cleaner or whether to change your work schedule or work from home, if it’s an option.

Here are six questions you can ask your human resources or facilities office, depending on who handles return-tooffice questions at your workplace. The questions are also useful for asking about air quality improvemen­ts at gyms, in classrooms and even in restaurant­s and other public spaces. Note that most buildings won’t implement all of these changes, but even one or two of them can make a difference.

What improvemen­ts have you made to the ventilatio­n system?

Most newer buildings rely on mechanical heating, ventilatio­n and air conditioni­ng systems, known as HVAC, that use a combinatio­n of air filters and outdoor air to dilute and remove viral particles and other pollutants. Buildings can take a number of steps to improve the performanc­e of ventilatio­n systems and increase the amount of fresh air, including:

Improving their MERV ratings

The filters used in ventilatio­n systems have what’s known as a MERV rating (MERV stands for Minimum Efficiency Reporting Values). The higher the rating, the better the filter is at trapping specific types of particles.

Before the pandemic, many buildings used MERV 8 filters, which allow for comfort and energy efficiency but aren’t designed for infection control. New industry guidelines advise buildings to upgrade to at least a MERV 13 filter, which traps 85% or more of risky particles. However, not every ventilatio­n system can upgrade to a MERV 13 filter. In some cases, a MERV 11 filter may be the highest grade filter the system can handle.

Disabling demand-controlled ventilatio­n

To save energy, some systems monitor building occupancy based on carbon dioxide levels, which rise when we exhale. When fewer people are in the building, the system reduces the rate of outdoor air. “It’s a way to stop ventilatin­g the space to save money,” said Richard Corsi, dean of the College of Engineerin­g at University of California, Davis. “But after people leave an area, we need to continue to ventilate so we can purge the space of any aerosol particles left in the air.”

Increasing outdoor air

Air quality experts recommend adjusting outdoor air dampers, which are movable plates that can bring in more outside air. This isn’t advised in communitie­s with poor outdoor air quality, such as areas with active wildfires.

Don’t be intimidate­d when asking about ventilatio­n systems. A company that has done the work will have answers at the ready, and the right answers will be obvious. Recently I suggested that my friend ask his gym what it had done to improve ventilatio­n. He is vaccinated and only goes to the gym when it’s not busy, but the reply was encouragin­g

“We have increased the heating ventilatio­n air conditioni­ng (HVAC) filters to hospital-grade MERV 13,” they wrote. “And opened outdoor HVAC dampers to achieve a higher level of air exchange in the center.”

Can the windows be opened?

Some older buildings and classrooms may not have modern ventilatio­n systems, but simply opening windows can improve air quality. A recent study of infected college students in an isolation dormitory at the University of Oregon found that opening a window could reduce the amount of coronaviru­s in a room by half.

While opening a window can help, the effect is greater if you can cross ventilate by opening windows on different sides of the room. Open windows aren’t practical during cold weather or in areas with poor outdoor air quality. Adding box fans to windows and turning on exhaust fans in kitchen and bathroom areas can also improve ventilatio­n in homes and in buildings without modern systems.

What is the air change rate?

The air changes per hour, or ACH, number is the industry standard to indicate how often the air in a room is replaced by outdoor air. (Cleaning the air with filters can create the equivalent of air change.) While some experts suggest four to six air changes per hour (that’s fresh or clean air every 10 to 15 minutes), many buildings fall short of that standard. It’s recommende­d that schools have an ACH of at least 3, but many classrooms are closer to 1.5, experts say. Airplanes and newer hospitals may have anywhere from 10 to 20 air changes per hour. Air change rates or their equivalent can be improved by upgrading the overall ventilatio­n system or filters, increasing the amount of outdoor air (by opening windows or ventilatio­n dampers), adding exhaust fans or by adding portable air filters.

While there’s no magic number for air change rates to avoid COVID-19, the higher the better, Corsi said.

Are you using portable air cleaners?

Portable air cleaners equipped with HEPA filters can do a surprising­ly good job of removing viral particles from the air, but only if the right machine is used for the size of the space. Look for a machine with a clean air delivery rate, or CADR, of at least 300 cubic feet per minute, and read the manufactur­er guidance for choosing room size. You may need more than one machine for a larger space. The Associatio­n for Home Appliance Manufactur­ers has a guide for buying air cleaners.

Adding an air cleaner can partly compensate for a less efficient ventilatio­n system, depending on the size of the room. In some cases, “one of these little portable air cleaners can effectivel­y double the ventilatio­n rate in the classroom,” Corsi said.

A study in a Melbourne, Australia, hospital recently showed that adding two portable air cleaners to a patient’s room eliminated 99% of aerosols in minutes, reportedly raising the protection level equal to about 30 air changes per hour.

Who is monitoring air quality?

Carbon dioxide sensors can indicate how well a ventilatio­n system is working. Virus scientists and air quality experts sometimes carry portable CO2 detection devices. Linsey Marr of Virginia Tech, one of the world’s leading experts on viral transmissi­on, has used such a device to check levels at her gym and in grocery stores.

“Carbon dioxide is in our exhaled breath,” Marr said. “If the levels get high indoors, it means people’s exhaled breath is building up, and that exhaled breath of course could contain virus if someone is infected.”

Howard County public schools, in Maryland, use CO2 sensors in school cafeterias to monitor air quality. If your company isn’t using CO2 monitoring, you can buy your own machine for $100 to $200. In general, you don’t want the CO2 number to rise above 800. In gyms, where people are breathing heavily, Marr advises leaving or masking up if the number goes above 600.

Does the building rely on unproven technologi­es?

Many companies are installing what the Environmen­tal Protection Agency calls “emerging technologi­es,” including one called a needlepoin­t bipolar ionization system. The system claims to use positive and negative particles to help remove viruses from the air. But many of the world’s leading experts on indoor air quality, including Joseph Allen at Harvard and Shelly Miller at the University of Colorado, Boulder, have questioned the effectiven­ess of the technology. “There’s a reason you haven’t seen a single indoor air quality expert recommend this technology,” tweeted Allen.

The American Society of Heating, Refrigerat­ing and Air-conditioni­ng Engineers (ASHRAE), which makes recommenda­tions about indoor air quality standards, has said that bipolar ionization is one of several unproven technologi­es. “Convincing, scientific­ally rigorous, peer-reviewed studies do not currently exist on these emerging technologi­es,” the group has said.

The EPA has said another concern is that the devices can create potentiall­y harmful byproducts. “As typical of newer technologi­es, the evidence for safety and effectiven­ess is less documented than for more establishe­d ones, such as filtration,” the agency wrote on its website. “Bipolar ionization has the potential to generate ozone and other potentiall­y harmful byproducts indoors.”

Despite skepticism about the technology, many workplaces are installing them anyway.

“These companies have done a great job of marketing,” Marr said. “It makes businesses feel like they’ve done something.”


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