6 questions to ask about the Covid and air quality at work


Whether you’re already back at your workplace or possibly returning to the office, 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 in 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 collect in spaces with poor airflow, such as airways. conference rooms. At the start of the pandemic, a coronavirus outbreak on the 11th floor of an office building in South Korea showed how one infectious person can increase the risk for everyone in a workplace. Of 216 people on the ground, 94 were infected. Most of those infected worked in rows of desks clustered on one side of the desk.

Even before Covid-19, it was clear that indoor air quality could affect the health of workers. 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-19, improving ventilation in schools and workplaces is key to stopping the spread of the coronavirus, said Dr Ashish K. Jha, Dean of Brown University School of Public Health.

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

In addition to asking about ventilation, you should ask about vaccination policies, staggered shifts to reduce capacity, Covid test plans, mask requirements, and how the building monitors. outside workers, such as delivery people and cleaning crews.

And while some technical details about air quality can be confusing, you don’t need to be a ventilation expert to determine what extra precautions your employer has taken to keep you safe during the pandemic. Asking questions about efforts to improve indoor air quality can help you make decisions about how much time you might spend there, whether it’s masking or buying a portable air purifier or whether to change your work schedule or work from home, if that’s an option.

Here are six questions you can ask your human resources or facilities office, depending on who is handling the back-to-office issues at your workplace. The questions are also useful for asking questions about air quality improvements in gyms, classrooms, and even 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.

Most newer buildings rely on mechanical heating, ventilation and air conditioning systems, known as HVAC, which use a combination of air and outside air filters to dilute and remove virus 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:

Filters used in ventilation systems have what is called a MERV rating (MERV stands for Minimum Efficiency Reporting Values). The higher the rating, the more capable the filter is of trapping specific types of particles.

Before the pandemic, many buildings used MERV 8 filters, which provide comfort and energy efficiency but are not designed for infection control. New industry guidelines advise vessels to upgrade to at least a MERV 13 filter, which traps 85% or more of at-risk particles. However, not all ventilation systems can upgrade to a MERV 13 filter. In some cases, a MERV 11 filter may be the highest quality filter the system can handle.

To save energy, some systems monitor building occupancy based on carbon dioxide levels, which increase as we breathe out. When there are fewer people in the building, the system reduces the flow of outside air. “It’s a way to stop ventilating space to save money,” said Richard Corsi, incoming dean of the College of Engineering at the University of California at Davis. “But after people leave an area, we have to continue to ventilate so that we can purge the space of any aerosol particles left in the air.”

Air quality experts recommend adjusting the outside air louvers, which are movable plates that can bring in more outside air. This is not advised in communities with poor outdoor air quality, such as areas with active forest fires.

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

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

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

While opening a window can help, the effect is greater if you can ventilate by opening windows from different sides of the room. Open windows are inconvenient in cold weather or in areas with poor outdoor air quality. Adding box fans to windows and turning on exhaust fans in kitchens and bathrooms can also improve ventilation in homes and buildings without modern systems.

The number of air changes per hour, or ACH, is the industry standard for indicating how often the air in a room is replaced with outside air. (Cleaning the air with filters can create the equivalent of an air change.) While some experts suggest four to six air changes per hour (that’s fresh or clean air every hour). every 10 to 15 minutes), many buildings do not meet this standard. It is recommended that schools have an ACH of at least 3, but many classrooms are closer to 1.5, experts say. Newer planes and hospitals can have between 10 and 20 air changes per hour. Air change rates or their equivalent can be improved by improving the overall ventilation system or filters, increasing the amount of outside air (by opening windows or ventilation shutters), adding ventilation fans. extraction or adding portable air filters.

While there is no magic number for air change rates to avoid Covid-19, the higher the better, said Dr Corsi.

Portable air purifiers with HEPA filters can do a surprisingly good job of removing virus 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 flow, or CADR, of at least 300 cubic feet per minute, and read the manufacturer’s advice for choosing the room size. You may need more than one machine for a larger space. The Association for Home Appliance Manufacturers has a guide to buying air purifiers.

Adding an air purifier can partially compensate for a less efficient ventilation system, depending on the size of the room. In some cases, “one of these small portable air purifiers can effectively double the ventilation rate in the classroom,” said Dr. Corsi.

A study at a Melbourne hospital recently showed that adding two portable air purifiers to a patient’s room removed 99% of aerosols within minutes, increasing the level of protection by around 30 air changes. per hour.

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

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

Public schools in Howard County, Maryland are using CO2 sensors in school cafeterias to monitor air quality. If your business doesn’t use CO2 monitoring, you can buy your own machine for $ 100 to $ 200. In general, you don’t want the CO2 count to go over 800. In gyms, where people breathe heavily, Dr. Marr advises leaving or masking if the count exceeds 600.

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

The American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE), which makes recommendations on indoor air quality standards, said bipolar ionization is one of many unproven technologies. “There are currently no compelling, scientifically rigorous, peer-reviewed studies on these emerging technologies,” the group said.

The EPA said another concern is that the devices can create potentially harmful byproducts. “As is typical of newer technologies, the evidence for safety and efficacy is less documented than for more established technologies, 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 install them anyway.

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


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