The tear gas causes a sharp pain in the body. Then cough, nausea and vomiting . But what causes these effects?
“It can be overwhelming and disabling. A person may be forced to close their eyes and cannot open them, ”said Sven-Eric Jordt, an anesthesiologist at Duke University.
Jordt has studied tear gas for more than a decade, although he doesn’t think that is the best term for the weapon.
THE COMPOSITION OF TEAR GAS
First of all, it is not a gas , but dust that rises in the air like a fine mist.
“I THINK OF TEAR GAS AS A PAIN GAS, BECAUSE IT DIRECTLY ACTIVATES PAIN DETECTION RECEPTORS .”
Weapons such as sarin gas cause muscle paralysis that can cause asphyxiation. It is designed to kill, while the purpose of tear gas is to repel manifestations.
Specifically, all tear gas agents activate one of the two pain receptors: TRPA1 or TRPV1 . These agents can be classified into two broad categories depending on which of those receptors they activate.
First category
The first category, TRPA1 activating agents , includes the chemical called 2-chlorobenzalmalonitrile or CS gas . It is commonly used by the police .
These agents are chlorine- containing compounds that are dispersed in the air as fine particles .
“IN REALITY, THEY DISPERSE WHEN BURNED AND DEPOSITED ON SKIN OR CLOTHING AND MAY PERSIST FOR A WHILE.”
They react chemically with biomolecules and proteins in the human body, which causes the sensation of severe burning .
These agents are rarely lethal , but deaths have occurred when used in confined spaces where people cannot escape.
Children have a particularly high risk of injury, as they have a smaller body surface and lungs.
A more potent compound
CS gas is the most common of these TRPA1 activating agents, but a newer compound has recently begun to be used: CS2 or CX .
This compound contains silicon so that it can last longer in the environment and does not disintegrate so quickly. The result is a more harmful tear gas that can continue to affect an area for several days .
There are two other TRPA1 activating agents used for the control of disturbances: CR gas (dibenzoxazepine) and CN gas (chloroacetophenone) .
Both are more powerful than CS gas. During the protests of the Arab Spring, it was reported that CN and CR gas were used together with CS gas, sometimes with a devastating effect.
Long after the protests, many miscarriages were reported in pregnant women who were exposed.
Second category
The second category of tear gas agents are pepper sprays that activate the TRPV1 pain receptor . These are derived mainly from capsaicin , the spice compound in chili peppers.
There are two compounds commonly used in this category: OC gas, a concentrated solution of natural capsaicin and PAVA , a mixture of synthetic capsaicin.
This category has fewer chemical or allergic reactions, but it is also an oil, so it is much harder to remove and can last longer.