When clouds of tear gas waft through the air, those nearby will feel their eyes become irritated as they begin to blink involuntarily. Their noses will burn and run, causing them to sneeze, while their lips and skin will feel as if they are on fire. They might begin to cough. But, ultimately, says Satya Achanta, an anesthesiologist at the Duke University School of Medicine who studies tear gas, the sensation feels like choking. “The victims feel as if they’re experiencing asphyxiation and chest tightness,” he says.
As mass demonstrations continue across all 50 states just over a week after the death of George Floyd, who was killed while in police custody in Minneapolis, law enforcement agencies have widely used tear gas to disperse protesters. According to Achanta, the sharp burning caused by tear gas compels victims to leave the area as they become unable to cope with pain and irritation. “They feel the urgency to flee from the scene, seeking fresh air,” he says.
But the widespread use of tear gas in these protests is also coinciding with a global disease pandemic that primarily affects the respiratory system. Achanta says the airborne chemicals could actually increase someone’s chance of becoming infected by the coronavirus — as well as boost the severity of tear gas’ toxic effects for both COVID-19 patients and asymptomatic carriers alike. Even though specific data on coronavirus patients is scarce, studies show that respiratory irritants like tear gas can increase the risk of infection for other lung conditions.
An Introduction to Tear Gas
Though the name suggests otherwise, the active compounds in tear gas are not actually gases, but solids. When a tear gas canister explodes, says Achanta, it sprays a mist of fine powder — including a chemical compound called 2-chlorobenzalmalonitrile, or CS gas — into the air. The powder then adheres to any moisture on the body, like the tear film on the surface of our eyes or moist nasal passages. “The tear gas makes victims unable to function by causing irritation to the eyes, mouth, nose, throat, lungs and skin,” says Achanta.
This battery of pain takes place because CS gas targets an ion channel called TRPA1, located on the sensory nerve endings of the skin and respiratory tract. “Their role is to send pain signals to the nervous system and alert the subject to (the presence of) noxious chemicals,” says Achanta. Beyond that, he continues, both short- and long-term exposure to these compounds can trigger the brain’s fear response.
But while canisters of CS gas are the type of tear gas most typically used by law enforcement, there are others, too. Pepper spray, for example, contains a cocktail of chemicals extracted from chili peppers, particularly a compound called capsaicin. This category of irritants targets a different pain receptor, TRPV1.
Tear Gas and Respiratory Distress
Exposure to CS tear gas can result in a broad array of health effects, including both acute and chronic consequences. Apart from instant irritation to the eyes, nose, mouth and respiratory tracts, it can also cause the skin to blister and burn. When used at close range, it can catalyze severe injuries to the eye. Studies in rats have shown that irritants that impact TRPA1 can significantly increase the risk of heart complications like an irregular heartbeat, suggesting similar responses in humans.
But a bulk of research on tear gas focuses on what it does to our airways and lungs. A 2014 U.S. Army study looked at more than 6,700 recruits who came into contact with CS tear gas, finding that they had a significantly higher risk of being diagnosed with acute respiratory illnesses than the controls. According to the Centers for Disease Control and Prevention, long-term exposure to tear gas — or simply receiving a high dose, particularly in tight spaces — can prompt potentially fatal respiratory failure. It can even cause immediate death from extreme chemical burns to the lungs and throat.
Achanta has studied tear gas since 2012, looking mainly at how it affects the respiratory system. “Exposure to higher concentrations can lead to conditions such as consistent cough [and] chronic bronchitis,” he says. “And previous studies showed that subjects who were exposed to CS tear gas became more susceptible to getting asthma.” Achanta also says these long-term consequences can be compounded by repeated exposures, with risks increasing alongside the duration that someone is breathing tear gas into their lungs.
When it comes to COVID-19, Achanta says those who have the disease may experience more severe symptoms of tear gas after inhaling the cloud of chemicals. For those people, the membrane that lines the respiratory tract and acts as a physical barrier against infection, known as the respiratory epithelium, is already compromised. “The victim will experience more severe effects of the tear gas agent because the particles can go into the respiratory tract and deep into respiratory tissues,” he says. “And the effects may last longer.”
For previously healthy people who come into contact with both tear gas and the coronavirus due to close proximity with fellow protesters, Achanta says the chances of the virus making its way into the lungs also shoots up. “The tear gas causes acute inflammation,” he says. “And that barrier is compromised, so the virus can get into the system more rapidly.”
And for those who are apparently healthy but asymptomatic, tear gas could cause their stress levels to spike — and potentially bring COVID-19 symptoms to the surface. “When there is stress, these microbial agents take the upper hand; these are opportunistic microorganisms,” says Achanta. “If an asymptomatic carrier is exposed to tear gas, (they) might become seriously ill.”
Protective Barriers
While there are no specific antidotes for counteracting tear gas’ acute (or long-term) effects, there are still ways for protesters to protect themselves. “These protesters should wear masks and goggles, or sunglasses at least,” says Achanta. “And these tear gases are heavier than air, so they try to settle near the ground level. [People] should always try to seek higher ground.” If you do come into contact with tear gas, he continues, you should immediately wash your eyes with water for 10 to 15 minutes and remove any contact lenses.
Beyond that, those participating in protests should try to stay away from the source of the billowing gas clouds. “And, obviously, (with) COVID-19, they should maintain social distancing,” adds Achanta. “Because we don’t know who is carrying (it), so there are some chances protesters could get infected.”
