Medical Examiner

We Just Don’t Know How Tear Gas and the Coronavirus Will Mix

Police officers wearing riot gear push back demonstrators shooting tear gas next to St. John's Episcopal Church.
Police officers shooting tear gas in D.C. on Monday. Jose Luis Magana/Getty Images

On Wednesday, Rep. Alexandria Ocasio-Cortez stood outside a Dunkin’ Donuts in Queens handing out N95 masks, an action that does not seem that out of place considering the pandemic, except that she was handing them out for people heading to protests, rather than just trying to provide them to citizens worried about the coronavirus.* “Teargas is a chemical banned in war and has no business being used by enforcement in the United States (or anywhere),” she captioned a photo on Instagram. “Wearing an N95 mask helps protect you from both spreading COVID-19 and exposure to tear gas more than surgical or cloth masks do.”

Here in America, we have spent the past couple months learning quite a bit about masks, the different types, and how much they can keep you safe. As a health reporter, I have done a lot of research already on N95 masks, and my take on Ocasio-Cortez’s advice is that it might be nominally correct: Tear gas particles are larger than a fraction of a micron, the particle size that N95s are capable of filtering. But N95s can only do that level of filtering (of tear gas, of viruses) when they are tight against the skin, forming a seal, and it’s hard to know if you are getting the right fit. Also, wearing an N95 properly can feel like breathing through a paper bag, one doctor told me earlier this year, which seems not ideal, if impossible, during a protest. The best way to protect yourself against tear gas is a respirator, but that is far more than most people can afford or use comfortably. At any rate, this attempt, by a congresswoman, to protect her constituents, was just the last thing that brought up the question I’ve had: How will tear gas and the coronavirus mix?

Tear gas is harmful to a healthy person. It might be more accurate to call it “pain gas,” a leading expert in the weapon Sven-Eric Jordt of Duke University has been saying for years. One review paper from 2003 describes the effects as “excessive flow of tears and closure of the eyelids, and incapacitation of exposed individuals.” It creates a burning sensation on any part of the body that’s moist—mouth, nose, sweat- or humidity-soaked skin. The effect on the lungs is a slew of bad stuff. As a 2018 review paper lays out, “respiratory manifestations can occur immediately such as cough, dyspnoea, haemoptysis, bronchoconstriction and laryngospasm; or after a latency period of up to 1 to 2 weeks causing hypersensitivity pneumonitis or reactive airways dysfunction syndrome.” Also, that paper notes, when people exposed to tear gas seek immediate care, it can hurt the health care workers.

How bad is the collision of tear gas and coronavirus? Add that to the list of terrible things we are going to learn. “I’ve been asked by multiple media outlets about tear gas and how it affects #SARSCoV2 transmission or #COVID19 severity,” tweeted Angela Rasmussen, a virologist at Columbia. “I don’t know. I’ve never had occasion to think about the effects of tear gas on respiratory virus pathogenesis during a pandemic.” She linked to the paper on tear gas and viral infection that she could find, which proved to be decades old, inaccessible, and also maybe not an actual study. She shared a ProPublica piece by Lisa Song that extensively lays out the potential links between damage and reactions to tear gas and increased susceptibility to the coronavirus. Song’s interviews with experts echo guidance from an open letter, signed by more than 1,000 health experts, which she also quotes. It notes that people should “oppose any use of tear gas, smoke, or other respiratory irritants, which could increase risk for COVID- 19 by making the respiratory tract more susceptible to infection, exacerbating existing inflammation, and inducing coughing.”

But like everything else about this pandemic, we won’t know the true extent of the effects for a while. Or maybe ever. While coronavirus transmission at the protests will show up in the data in the next few weeks, Song writes, “many who are affected [by tear gas] will be reluctant or afraid to seek medical help.” With tear gas, as with the coronavirus, we are left in the meantime to reduce risk with imperfect information and supplies as best we can.

Correction, June 5, 2020: This post originally misspelled Alexandria Ocasio-Cortez’s first name.