The harrowing moment is captured as a Hong Kong police officer and a member of the press both feel the devastating effect of tear gas today (September 3).

“The known impact of tear gas is not great for your health, and then there are side effects and unintended consequences that are also not great,” said Rohini J. Haar, M.D., a visiting professor at the UC Berkeley School of Public Health, to media outlets.

In general, tear gas causes a stinging and burning sensation to a person’s eyes and mucus membranes (including those in the lungs), salivation, watery eyes, runny nose, tight chest, headache, and nausea, the World Health Organization (WHO) said.

“It causes your skin to feel like it’s burning and, when you breathe it in (which you can’t help but do because it’s a gas), it can cause injury to your airways and lungs,” Dr. Haar explains. “All of the symptoms are supposed to be temporary, like lasting 20 to 30 minutes, but if you can’t get out of the tear gas, there’s too much of it, or you’re specifically vulnerable to it, it can cause a lot more problems.”

2nd September 2019 outside Mong Kok Police Station, police fired tear gas without any warning, leaving some police officers and press suffering from the effects of tear gas.