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Over 10,000 tear gas canisters have been fired in Hong Kong's vicious protests, and it could have long-term consequences for the city's health

hong kong protests tear gas hong kong protests tear gas
Associated Press/Kin Cheung


During that time, a record number of tear gas canisters were fired by police during clashes, exposing an estimated 88% of Hong Kong's 7.4 million residents to the chemical. The Associated Press estimates that more than 10,000 canisters have been fired. 

The prolonged use of the riot control method, particularly in confined areas like metro stations and near shopping centers, has prompted concern among experts and locals about the effects of long-term exposure. 

"What's going on in Hong Kong is pretty unprecedented," Alistair Hay, a British toxicologist from the University of Leeds, told AP in December.


tear gas mask
AP Photo/Ng Han Guan, File

Anna Feigenbaum, author of the book "Tear Gas: From the Battlefields of WWI to the Streets of Today" and tear gas researcher, discussed the striking amount of tear gas unleashed on Hong Kong and the possible impact it would have on the health of the city. 


Hong Kong is a densely-packed city 



According to the United Nations figures from 2017, Hong Kong has a density of 26,000 people per square kilometer, or about 10,000 per square mile.


Hong Kong police have been firing tear gas at close distances 


Although officers firing tear gas at crowds are supposed to account for weather conditions — especially wind — and the layout of the area, video footage has shown police firing tear gas from a close distance and aiming canisters at people instead of the ground. 

For these reasons, the relative safety of using tear gas as a crowd dispersal method is difficult to calculate in Hong Kong, and the effects on the population become "more potent."

"The safety of tear gas is determined by the amount of the toxin that is in a canister per metres squared," Feigenbaum told Business Insider.


"So releasing 50 canisters in an open street with clear ways off the street in normal air conditions is more 'safe' than releasing 50 canisters in a transit station or on a blocked road. Likewise, being next to a canister makes it far more 'unsafe' than being 50 metres from one."

Long-term exposure to tear gas puts the population at risk

hong kong protest tear gas
Anthony Kwan/Getty Images






"It is very difficult to study because you cannot isolate or make separate what health conditions are caused by tear gas versus other environmental, social and genetic conditions," Feigenbaum said. 



Though protests in Hong Kong have quieted in the last few weeks, scores of protesters took to the streets on New Year's Eve, leading to violent clashes between protesters and police, who fired water cannons and pepper spray at crowds. 


In November, pro-democracy candidates won hundreds of seats in Hong Kong's local elections. And last month, US President Donald Trump signed a bill meant to defended human rights in Hong Kong. 


On Thursday, Lam said the status quo could continue beyond 2047 as long as the city's "loyalty" to Beijing was upheld.


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