Gas mask in the context of "Respirator"

Riot control is a form of public order policing used by law enforcement, military, paramilitary or security forces to control, disperse, or arrest people who are involved in a riot, demonstration or protest.

If a riot is spontaneous, then actions which cause people to stop and think (e.g. loud noises or issuing instructions in a calm tone) can be enough to stop it. However, these methods usually fail when there is severe anger, or the riot was planned or organized. Riot control personnel have long used less lethal weapons such as batons and whips to disperse crowds and detain rioters. Since the 1980s, riot control officers have also used tear gas, pepper spray, rubber bullets, stun grenades, and electric tasers. In some cases, riot squads may also use Long Range Acoustic Devices, water cannons, armoured fighting vehicles, aerial surveillance, police dogs or mounted police on horses. Persons performing riot control typically wear protective equipment such as riot helmets, face visors, body armor (vests, neck protectors, knee pads, etc.), gas masks and riot shields. Even though riot tactics are effective in controlling crowds, they can also lead to significant psychological effects on both the rioters and the police. Exposure to intense fear, stress, and violence during these confrontations can result in long-term mental health issues, like anxiety, post-traumatic stress disorder (PTSD), and heightened aggression, which can impact the well-being of protesters and police officers.

An alder carr is a particular type of carr, i.e. waterlogged wooded terrain populated with alder trees. They can be found across the United Kingdom, sometimes attracting Ash trees should they become drier. Many have developed alongside streams in the New Forest, where the Alder's capacity to thrive in a water logged environment allows them to become the dominant species of tree in these areas. The presence of particular bacteria, Frankia alni, enables their root systems to extract nitrogen from the air, thus making up for the lack of nitrogen in waterlogged soil.

Alder carrs have often been coppiced, whereby cutting away growth at ground level encourages new trunks to grow at ground level. This means the wood can be repeatedly harvested. This wood can then be used to make water pipes, wooden pumps, as well as piles under bridges. Other uses have included charcoal for making gun powder, and filters for gas masks.

The M17 Protective Mask is a series of gas masks that were designed and produced in 1959 (as a replacement of the M-9 gas mask) to provide protection from all types of known chemical and biological agents present. The M-17 was issued to troops in the Vietnam War, and was standard issue for the U.S. Military until it was replaced by the M40 Field Protective Mask for the U.S. Army and USMC in the mid 1990s while the U.S. Air Force and U.S. Navy replaced it for the MCU-2/P Gas Mask in the mid-1980s.

A riot protection helmet or riot helmet is a type of helmet designed for law enforcement and military use to protect the wearer's head, face and eyes from handheld melee weapons, and thrown projectiles such as bricks, as may be met in riot control. Many modern riot squad helmets are reinforced with materials that will protect the wearer from dangerous substances such as acids or industrial chemicals. The riot protection helmets are usually made to be able to easily fit a gas mask, especially when tear gas is being used.

There have been rare cases of riot protection helmets being worn to protect against objects blown by tornadoes or fierce storms, for example in England in the 18 January 2007 gale.