4 main factors determine your risk of getting the coronavirus in any situation. Here's how daily activities stack up.

• The coronavirus typically spreads via droplets when people are in sustained, close proximity to someone sick.
• Four factors raise your risk of catching the virus: enclosed spaces, crowds, close contact with others, and difficulty social distancing.
• One chart shows how these risk factors come into play during various daily activities.

As the US welcomes warmer weather and relaxed stay-at-home orders, a new type of day-to-day risk assessment is emerging as Americans evaluate the safety of their activities.

Experts have pinpointed a few factors that distinguish low- and high-risk situations.

"This virus really likes people being indoors in an enclosed space for prolonged periods of close face-to-face contact," William Schaffner, a professor of preventive medicine at Vanderbilt University, previously told Business Insider.

That's because the coronavirus primarily spreads via droplets that fly through the air when an infected person coughs, sneezes, or speaks. A recent study found your risk of infection primarily has to do with how close you get to people and for how long.

It's not surprising, then, that evidence increasingly shows that the risk of infection is higher in enclosed, crowded spaces where it's difficult to maintain 6 feet of social distance and people are in close contact.

Here's how daily activities stack up in terms of coronavirus risk, based on those four factors:

Your risk of infection is most likely lower outside than indoors. So camping, swimming, and hiking, for example, are low-risk activities compared to eating indoors at a restaurant, getting your hair cut, or attending an in-person worship service.

Indoor activities come with their own spectrum of risk — based on the factors listed above, exercising at a gym may come with less risk than partying at a nightclub, while shopping may be less risky than attending a party.

Ventilation and mask-wearing practices influence your risk, too

According to Schaffner, the most important thing to consider when evaluating an activity or a place is how well you can social distance.

"I'm most concerned about how far apart I am from my fellow patrons," he said, adding, "It continues to be prudent to keep as distant from people as possible," regardless of whether you're indoors or outside.

But there are other factors that can increase your risk of infection, of course. Schaffner recommended checking whether patrons and staff at stores and restaurants are wearing masks, for example. If they're not, go somewhere else, he said.

Another factor is how well ventilated a space is. Scientists still aren't certain to what degree a cloud of tiny coronavirus particles — known as aerosols — can linger in the air and infect the next person who walks by. But research has suggested that more live viral particles are found in the air in enclosed rooms with little airflow.

Poorly ventilated elevators, for example, could be a hotspot for exposure, Schaffner said.

Lastly, he suggested minimizing how long you spend in an indoor space that's not your home.

"The farther away you are and the shorter duration of contact between you and other people means you get less efficient virus transmission," Schaffner said.

Countries that placed an emphasis on combatting these risk factors in their coronavirus response have seen more success in curbing their outbreaks without fully locking down.

Japan, for example, avoided a blanket stay-at-home order by telling its citizens to steer clear of the 3 C's: closed spaces, crowded places, and close-contact settings.

But even armed with this information, Schaffner said, there's no such thing as a safe way to participate in daily activities during the pandemic.

"'Safe' implies something absolute. Instead, it's all about risk reduction," he added.