A smoke composition is a

pyrotechnic composition A pyrotechnic composition is a substance or mixture of substances designed to produce an effect by heat, light, sound, gas/smoke or a combination of these, as a result of non-detonative self-sustaining exothermic reaction, exothermic chemical reac ...

designed primarily to generate

smoke Smoke is an aerosol (a suspension of airborne particulates and gases) emitted when a material undergoes combustion or pyrolysis, together with the quantity of air that is entrained or otherwise mixed into the mass. It is commonly an unwante ...

. Smoke compositions are used as obscurants or for generation of signaling smokes. Some are used as a payload of

smoke bomb A smoke bomb is a firework designed to produce a large amount of smoke upon ignition. History Early Japanese history saw the use of a rudimentary form of the smoke bomb. Explosives were common in Japan during the Mongol invasions of the 13th ...

s and

smoke grenade A smoke grenade is a canister-type grenade used as a signaling device, target or landing zone marking device, or as a screening device for unit movements. Smoke grenades are generally more complex and emit a far larger amount of smoke than sm ...

Obscurants

Smoke compositions used as obscurants generate large amount of thick, usually white, smoke.

Zinc chloride smoke

White phosphorus

White phosphorus White phosphorus, yellow phosphorus, or simply tetraphosphorus (P4) is an allotrope of phosphorus. It is a translucent waxy solid that quickly yellows in light (due to its photochemical conversion into red phosphorus), and impure white phospho ...

is a popular base for smoke production. It is used in artillery shells, bombs, and grenades.

Signalling

colored smoke Colored smoke is a kind of smoke created by an particulate, aerosol of small particles of a suitable pigment or dye. Colored smoke can be used for smoke signals, often in a military context. It can be produced by smoke grenades, or by various ...

composition can be used for signalling. These are usually based on a low-temperature burning pyrotechnic composition, mixed with a

dye Juan de Guillebon, better known by his stage name DyE, is a French musician. He is known for the music video of the single "Fantasy Fantasy is a genre of speculative fiction that involves supernatural or Magic (supernatural), magical ele ...

that gets vaporized and creates large, colored smoke particles. The composition is often based on an oxidizer (e.g.

potassium chlorate Potassium chlorate is the inorganic compound with the molecular formula KClO3. In its pure form, it is a white solid. After sodium chlorate, it is the second most common chlorate in industrial use. It is a strong oxidizing agent and its most impor ...

potassium nitrate Potassium nitrate is a chemical compound with a sharp, salty, bitter taste and the chemical formula . It is a potassium salt of nitric acid. This salt consists of potassium cations and nitrate anions , and is therefore an alkali metal nit ...

, or

potassium perchlorate Potassium perchlorate is the inorganic salt with the chemical formula K Cl O4. Like other perchlorates, this salt is a strong oxidizer when the solid is heated at high temperature, although it usually reacts very slowly in solution with reducin ...

), a fuel (e.g.

lactose Lactose is a disaccharide composed of galactose and glucose and has the molecular formula C12H22O11. Lactose makes up around 2–8% of milk (by mass). The name comes from (Genitive case, gen. ), the Latin word for milk, plus the suffix ''-o ...

), an optional coolant (e.g.

sodium bicarbonate Sodium bicarbonate ( IUPAC name: sodium hydrogencarbonate), commonly known as baking soda or bicarbonate of soda (or simply “bicarb” especially in the UK) is a chemical compound with the formula NaHCO3. It is a salt composed of a sodium cat ...

), and one or more dyes.

Fire extinguishing

Smoke with a suitable composition can be used as a

fire suppression agent A fire retardant is a substance that is used to slow down or stop the spread of fire or reduce its intensity. This is commonly accomplished by chemical reactions that reduce the flammability of fuels or delay their combustion. Fire retardants m ...

. A

similar to

black powder Gunpowder, also commonly known as black powder to distinguish it from modern smokeless powder, is the earliest known chemical explosive. It consists of a mixture of sulfur, charcoal (which is mostly carbon), and potassium nitrate, potassium ni ...

, composed of 15%

charcoal Charcoal is a lightweight black carbon residue produced by strongly heating wood (or other animal and plant materials) in minimal oxygen to remove all water and volatile constituents. In the traditional version of this pyrolysis process, ca ...

and 85%

, generates thick smoke composed of particles of mainly

potassium carbonate Potassium carbonate is the inorganic compound with the formula . It is a white salt, which is soluble in water and forms a strongly alkaline solution. It is deliquescent, often appearing as a damp or wet solid. Potassium carbonate is mainly used ...

, which has fire extinguishing properties. Two-kilograms

s, thrown into burning rooms through plate-glass windows, have been used by some European

firefighter A firefighter (or fire fighter or fireman) is a first responder trained in specific emergency response such as firefighting, primarily to control and extinguish fires and respond to emergencies such as hazardous material incidents, medical in ...

s.{{Cite book , url=https://books.google.com/books?id=yxRyOf8jFeQC&dq=popcorning&pg=PA85 , title = The Chemistry of Fireworks, isbn = 9780854041275, last1 = Russell, first1 = Michael S., year = 2009, publisher=Royal Society of Chemistry

Dispersion of chemicals

Smoke compositions can be used also for creating

aerosol An aerosol is a suspension (chemistry), suspension of fine solid particles or liquid Drop (liquid), droplets in air or another gas. Aerosols can be generated from natural or Human impact on the environment, human causes. The term ''aerosol'' co ...

of other materials than dyes. Generally the same type of pyrotechnic composition as for colored smokes is used, with the dye being replaced by the desired chemical. The devices usually have the form of

s. The best known such application of smoke compositions is in

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

, for dispersion of lachrymatory agents. The agent used is most often

CS gas The compound 2-chlorobenzalmalononitrile (also called ''o''-chlorobenzylidene malononitrile; chemical formula: C10H5ClN2), a cyanocarbon, is the defining component of the lachrymatory agent commonly referred to as CS gas, a tear gas which ...

, with less used alternatives

CR gas CR gas or dibenzoxazepine (chemical name dibenz 'b'',''f''1,4]oxazepine, is an incapacitating agent and a lachrymatory agent. CR was developed by the British Ministry of Defence (United Kingdom), Ministry of Defence as a riot control agent in t ...

, CN gas and

Adamsite Adamsite or DM is an organic compound; technically, an arsenical diphenylaminechlorarsine, that can be used as a riot control agent. DM belongs to the group of chemical warfare agents known as vomiting agents or sneeze gases. First synthesized ...

. In agriculture, smoke compositions are used to disperse

insecticide Insecticides are pesticides used to kill insects. They include ovicides and larvicides used against insect eggs and larvae, respectively. The major use of insecticides is in agriculture, but they are also used in home and garden settings, i ...

s and

fungicide Fungicides are pesticides used to kill parasitic fungi or their spores. Fungi can cause serious damage in agriculture, resulting in losses of yield and quality. Fungicides are used both in agriculture and to fight fungal infections in animals, ...

s. Some agents used in this manner are

permethrin Permethrin is a medication and an insecticide. As a medication, it is used to treat scabies and lice. It is applied to the skin as a cream or lotion. As an insecticide, it can be sprayed onto outer clothing or mosquito nets to kill the insects ...

cypermethrin Cypermethrin (CP) is a synthetic pyrethroid used as an insecticide in large-scale commercial agricultural applications as well as in consumer products for domestic purposes. It behaves as a fast-acting neurotoxin in insects. It is easily degrad ...

chlorpyrifos Chlorpyrifos (CPS), also known as chlorpyrifos ethyl, is an organophosphate pesticide that has been used on crops, animals, in buildings, and in other settings, to kill several pests, including insects and worms. It acts on the nervous systems ...

, imazalil, et

and some

fumigation Fumigation is a method of pest control or the removal of harmful microorganisms by completely filling an area with gaseous pesticides, or fumigants, to suffocate or poison the pests within. It is used to control pests in buildings (structural ...

agents. Smoke compositions can be also used for

weather modification Weather modification is the act of intentionally manipulating or altering the weather. The most common form of weather modification is cloud seeding, which increases rainfall or snowfall, usually for the purpose of increasing the local water su ...

, namely

cloud seeding Cloud seeding is a type of weather modification that aims to change the amount or type of precipitation, mitigate hail, or disperse fog. The usual objective is to increase rain or snow, either for its own sake or to prevent precipitation from ...

, to provide

cloud condensation nuclei Cloud condensation nuclei (CCNs), also known as cloud seeds, are small particles typically 0.2 μm, or one hundredth the size of a cloud droplet. CCNs are a unique subset of aerosols in the atmosphere on which water vapour condenses. This c ...

for the moisture to precipitate.

References

Pyrotechnic compositions Smoke Fire suppression agents