Read This Before You Even Consider Dining Indoors

Experts explain the many risks involved — and how to lower your risk if you decide to do it

Photo: Jeff Gritchen/MediaNews Group/Orange County Register/Getty Images

Linsey Marr has not dined indoors at a restaurant since the pandemic began, and she won’t until it’s over. Because she knows the risk, better than just about anyone. Marr, PhD, is a scientist at Virginia Tech and an expert on the transmission of the coronavirus through the air. She and several of her colleagues agree that the riskiest environments for catching Covid-19 are crowded indoor spaces, including restaurants.

“Restaurants are among the higher-risk activities because you’re indoors with other people without masks for some of the time at least,” Marr tells Elemental.

The coronavirus spreads in three known ways: from infected surfaces, by large respiratory droplets that typically fall to the ground within a few feet, and in smaller droplets called aerosols that can stay suspended for minutes or hours — a particular risk in poorly ventilated buildings where the aerosol concentration can build up.

The risk of airborne transmission increases with several factors related to dose and duration.

• The louder a person talks, the more aerosols are released.
• If you’re closer to someone or more than one person in a room is sick (even if they don’t know it), the risk rises.
• If you stay in an infected space for, say, an hour, your odds of getting sick are higher than if you spend less than 15 minutes there, but there are no firm thresholds given the many other variables.

The relative extent of each transmission mode is not known, so Marr, and other scientists and health experts encourage hand-washing as well as physical distancing, mask-wearing, and avoiding large crowds as the keys to slowing the spread.

The risk, they say, is much greater in a crowded, poorly ventilated restaurant than an uncrowded, well-ventilated one and much greater when people don’t wear masks. In an FAQ on the topic, 10 aerosol-transmission experts point out that many outbreaks have been documented in crowded indoor spaces where people spend a lot of time together and especially when there is a lot of loud talking…