How Bad Indoor Air Quality Can Affect Your Brain

While we tend to worry about inhaling viral particles like the coronavirus, new research shows the air quality at work may have subtle effects on cognitive function.,


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How healthy is the air in your workplace?

It’s a question many of us are now asking to protect ourselves from Covid-19. But indoor air quality is also something we should be talking about long after the pandemic ends. Because not only can the quality of your workplace air influence the number of sick days you take each year, but it may even affect how well your brain works in the office.

A new study shows that poor indoor air quality is associated with subtle impairments in a number of cognitive functions, including our ability to concentrate and process information. The study tracked 302 office workers in commercial buildings in six countries — the United States, Britain, China, India, Mexico and Thailand — for 12 months.

The scientists used monitors to measure ventilation and indoor air quality in the buildings, including levels of fine particulate matter, which includes dust and minuscule particles from smoking, cleaning products and outdoor air pollution that seeps into the building. The workers were asked to use an app to take regular cognitive tests during the workday. The tests included simple math problems, as well as a tricky color and word brain teaser called the Stroop test, in which a word like “blue” or “purple” is printed in green or red ink. (The test asks you to name the color of the ink, but our brains want to read the word instead. You can try the Stroop test yourself here.)

The study found that the office workers in buildings with the poorest indoor air quality tended to perform worse on the brain teasers. While the effect wasn’t dramatic, the findings add to a growing body of evidence suggesting that the air we breathe affects brain health.

“This study looked at how several factors in the indoor environment have an immediate impact on our cognitive function and performance,” said Joseph G. Allen, the director of the Harvard Healthy Buildings program and the study’s senior author. “This study shows that the air you’re breathing at your desk at that moment has an impact on how well you think.”

In the past, air quality control in buildings has been mostly focused on energy efficiency and comfort, with little consideration given to infection control or overall worker health. But the pandemic has prompted many workplaces to take a closer look at indoor air quality. The good news is that many of the changes being made to prevent the spread of Covid-19 are the same improvements that need to be made to improve the overall air quality linked with cognitive function and worker productivity.

“There is a newfound appreciation for how much the indoor environment influences our health,” said Dr. Allen. “Healthy buildings,” he said, should not just be thought of as “something we do during Covid or a crisis. It has to be the new normal, not the exception, going forward.”

Is your building doing everything it needs to keep you safe? This week I spoke to some of the world’s leading air quality experts about the 6 Questions to Ask About Covid and Air Quality at Work.

In general, you want to hear that your building has upgraded its ventilation filters to at least a MERV 11 but preferably a MERV 13, which is an indicator of filtration efficiency. You also want to know if building managers have taken steps to increase outdoor air or added portable air cleaners to the space. Be wary if someone tells you the building’s ventilation system can’t be improved or that they’re using a new, unproven technology.

Dr. Allen notes that even adding a portable air cleaner with a HEPA filter to the center of the room can make a meaningful difference in offices with less efficient ventilation systems. The key to choosing an air cleaner is to pick the right device for the size of the room. Dr. Allen advises that for a typical work space, choose an air cleaner with a clean air delivery rate, or CADR, of 300 for every 500 square feet of floor space — which provides about the equivalent of changing the air in the room every 15 minutes. Wirecutter, the product review site owned by The Times, has a useful review of portable air cleaners.

Dr. Allen is the co-author of a new book, “Healthy Buildings: How Indoor Spaces Drive Performance and Productivity.” He said he’s been encouraged to see more businesses and individuals taking indoor air quality more seriously as a result of the pandemic. Recently he saw a job posting at a major company advertising for a “head of healthy buildings” in the company’s global real estate division.

“It tells you that serious companies are changing how they approach their buildings, and they’re not thinking about this as a one-off during Covid,” said Dr. Allen.

While some of the technical details around air quality can be confusing, don’t be intimidated. You don’t have to be a ventilation expert to determine if the precautions your employer is taking are adequate to keep you safer during the pandemic and well into the future.

“The pressure is coming from employees, parents of kids in school, teachers — there’s a heightened level of awareness and expertise,” said Dr. Allen. “How many people were talking about MERV 13 filters prior to the pandemic? This knowledge that our indoor spaces have been underperforming is not going away. I think people are rightly frustrated and fed up with it.”

Learn how to talk about indoor air quality:
6 Questions to Ask About Covid and Air Quality at Work

Staying safe in a car during a flash flood

Flash food warnings are getting more common, even in areas that have never experienced severe flooding before. Flash floods can develop quickly, within hours or even minutes, which means we all need to be prepared for them. I was especially interested to read this week about how to stay safe in your car during flash flooding.

Nearly half of all flash flood deaths are vehicle-related, which is why you should never ignore barriers or attempt to power through flooded areas. Just 12 inches of water can float your car and 18 inches can carry off your SUV or pickup truck.

That said, if your car does get taken by floodwaters, first, roll down your windows, said Lynn Burttschell, an emergency medical worker, rescue swimmer and founder of Wimberley Rescue Training. If they won’t budge, he recommended breaking the glass with an escape tool (like the one in this Wirecutter guide, which you can store in your glove compartment) or using the metal pole of your headrest as a ram. Opening the windows is important, Mr. Burttschell said, because “if the water continues to rise, then that car fills up and becomes more of a rock instead of a bobber floating downstream.”

Then, unbuckle your seatbelt and grip it as you climb onto the roof and call 911, Mr. Burttschell advised. Do your best to remain with the car until help arrives. Lie down on the roof to keep yourself stable, and don’t tie yourself to the car, in case it rolls.

During his 32-year career, Mr. Burttschell has found that people who stay with their cars survive at much higher rates than those who abandon them, simply because it’s easier for emergency services to spot a vehicle than a person. “I really don’t ever recommend leaving the vehicle,” he said. To make yourself more noticeable, you can also turn on your hazard lights, activate your car’s alarm with your key fob and, if possible, honk the horn.

Read more about flash floods:
How to Stay Safe During a Flash Flood

How to clean everything

I really enjoy the Wirecutter series “Clean Everything.” You’ll learn how to clean your cast iron skillet, your laptop and your bed pillows, among other things. You can also subscribe to the Clean Everything newsletter.

Learn more:
How to Clean Your Glasses

The Week in Well

Here are some more stories you don’t want to miss:

Gretchen Reynolds asks: How much exercise do we need to live longer?

Jane Brody shares her wisdom about how to age gracefully.

Christina Caron looks at alarming suicide rates among Black girls.

Nicholas Bakalar writes about electroconvulsive therapy for depression.

And of course, we’ve got the Weekly Health Quiz.

Let’s keep the conversation going. Follow me on Facebook or Twitter for daily check-ins, or write to me at

Stay well!

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