This article is about the collection of airborne particulates and gases. For the practice of smoking, seeSmoking. For other uses, seeSmoke (disambiguation).
The visibleparticulate matter in such smokes is most commonly composed ofcarbon (soot). Other particulates may be composed of drops of condensed tar, or solid particles of ash. The presence of metals in the fuel yields particles of metaloxides. Particles of inorganicsalts may also be formed, e.g.ammonium sulfate,ammonium nitrate, orsodium chloride. Inorganic salts present on the surface of the soot particles may make themhydrophilic. Many organic compounds, typically thearomatic hydrocarbons, may be alsoadsorbed on the surface of the solid particles. Metal oxides can be present when metal-containing fuels are burned, e.g.solid rocket fuels containingaluminium.Depleted uranium projectiles after impacting the target ignite, producing particles ofuranium oxides.Magnetic particles, spherules ofmagnetite-likeferrous ferric oxide, are present in coal smoke; their increase in deposits after 1860 marks the beginning of the Industrial Revolution.[16] (Magnetic iron oxidenanoparticles can be also produced in the smoke frommeteorites burning in the atmosphere.)[17] Magneticremanence,recorded in the iron oxide particles, indicates the strength of Earth's magnetic field when they were cooled beyond theirCurie temperature; this can be used to distinguish magnetic particles of terrestrial and meteoric origin.[18]Fly ash is composed mainly ofsilica andcalcium oxide.Cenospheres are present in smoke from liquid hydrocarbon fuels. Minute metal particles produced byabrasion can be present in engine smokes.Amorphous silica particles are present in smokes from burningsilicones; small proportion ofsilicon nitride particles can be formed in fires with insufficient oxygen. The silica particles have about 10 nm size, clumped to 70–100 nm aggregates and further agglomerated to chains.[10] Radioactive particles may be present due to traces ofuranium,thorium, or otherradionuclides in the fuel;hot particles can be present in case of fires duringnuclear accidents (e.g.Chernobyl disaster) ornuclear war.
Smoke particulates, like other aerosols, are categorized into three modes based on particle size:
nuclei mode, withgeometric mean radius between 2.5 and 20 nm, likely forming by condensation of carbonmoieties.
accumulation mode, ranging between 75 and 250 nm and formed by coagulation of nuclei mode particles
Most of the smoke material is primarily in coarse particles. Those undergo rapiddry precipitation, and the smoke damage in more distant areas outside of the room where the fire occurs is therefore primarily mediated by the smaller particles.[19]
Aerosol of particles beyond visible size is an early indicator of materials in a preignition stage of a fire.[10]
Burning of hydrogen-rich fuel produceswater vapor; this results in smoke containing droplets of water. In absence of other color sources (nitrogen oxides, particulates...), such smoke is white andcloud-like.
Some components of smoke are characteristic of the combustion source.Guaiacol and its derivatives are products of pyrolysis oflignin and are characteristic ofwood smoke; other markers aresyringol and derivates, and othermethoxyphenols.Retene, a product of pyrolysis ofconifer trees, is an indicator offorest fires.Levoglucosan is a pyrolysis product ofcellulose.Hardwood vssoftwood smokes differ in the ratio of guaiacols/syringols. Markers for vehicle exhaust includepolycyclic aromatic hydrocarbons,hopanes,steranes, and specific nitroarenes (e.g.1-nitropyrene). The ratio of hopanes and steranes to elemental carbon can be used to distinguish between emissions of gasoline and diesel engines.[20]
Many compounds can be associated with particulates; whether by beingadsorbed on their surfaces, or by being dissolved in liquid droplets. Hydrogen chloride is well absorbed in the soot particles.[19]
Inert particulate matter can be disturbed and entrained into the smoke. Of particular concern are particles ofasbestos.
Polymers are a significant source of smoke. Aromaticside groups, e.g. inpolystyrene, enhance generation of smoke. Aromatic groups integrated in the polymer backbone produce less smoke, likely due to significantcharring. Aliphatic polymers tend to generate the least smoke, and are non-self-extinguishing. However presence of additives can significantly increase smoke formation. Phosphorus-based and halogen-basedflame retardants decrease production of smoke. Higher degree ofcross-linking between the polymer chains has such effect too.[21]
Smoke from awildfireSmoke rising up from the smoldering remains of a recently extingished mountain fire in South Africa
Thenaked eye detects particle sizes greater than 7 μm (micrometres).[22]Visible particles emitted from a fire are referred to as smoke.Invisible particles are generally referred to as gas or fumes. This is best illustrated whentoasting bread in a toaster. As the bread heats up, the products of combustion increase in size. The fumes initially produced are invisible but become visible if the toast is burnt.
Anionization chamber typesmoke detector is technically a product of combustion detector, not a smoke detector. Ionization chamber type smoke detectors detect particles of combustion that are invisible to the naked eye. This explains why they may frequentlyfalse alarm from the fumes emitted from the red-hot heating elements of a toaster, before the presence of visible smoke, yet they may fail to activate in the early, low-heatsmoldering stage of a fire.
Smoke from a typical house fire contains hundreds of different chemicals and fumes. As a result, the damage caused by the smoke can often exceed that caused by the actual heat of the fire. In addition to the physical damage caused by the smoke of afire – which manifests itself in the form of stains – is the often even harder to eliminate problem of a smoky odor.
Smoke from oxygen-deprived fires contains a significant concentration of compounds that are flammable. A cloud of smoke, in contact with atmospheric oxygen, therefore has the potential of being ignited – either by another open flame in the area, or by its own temperature. This leads to effects likebackdraft andflashover.Smoke inhalation is also a danger of smoke that can cause serious injury and death.[23]
Processing fish while being exposed to smoke
Many compounds of smoke from fires are highly toxic and/or irritating. The most dangerous iscarbon monoxide leading tocarbon monoxide poisoning, sometimes with the additive effects ofhydrogen cyanide andphosgene. Smoke inhalation can therefore quickly lead to incapacitation and loss of consciousness. Sulfur oxides, hydrogen chloride and hydrogen fluoride in contact with moisture formsulfuric,hydrochloric andhydrofluoric acid, which are corrosive to both lungs and materials.
World Trade Center on fire after terrorists flew planes into the buildings on September 11, 2001
Cigarette smoke is a major modifiable risk factor forlung disease,heart disease, and manycancers. Smoke can also be a component of ambient air pollution due to the burning of coal in power plants, forest fires or other sources, although the concentration of pollutants in ambient air is typically much less than that in cigarette smoke. One day of exposure to PM2.5 at a concentration of 880 μg/m3, such as occurs in Beijing, China, is the equivalent of smoking one or two cigarettes in terms of particulate inhalation by weight.[24][25] The analysis is complicated, however, by the fact that the organic compounds present in various ambient particulates may have a higher carcinogenicity than the compounds in cigarette smoke particulates.[26] Secondhand tobacco smoke is the combination of both sidestream and mainstream smoke emissions from a burning tobacco product. These emissions contain more than 50 carcinogenic chemicals. According to the United StatesSurgeon General's 2006 report on the subject, exposures to secondhand tobacco smoke can activate platelets causing increased clotting and increased risk of thrombus and potentially damage the lining of blood vessels, decrease coronary flow velocity reserves, and reduce heart rate variability, potentially increasing the risk of a heart attack. The chances of these effects occurring increase with increased exposure and time of exposure.[27] The American Cancer Society lists "heart disease, lung infections, increased asthma attacks, middle ear infections, and low birth weight" as ramifications of smoker's emission.[28]
Smoke can obscure visibility, impeding occupant exiting from fire areas. In fact, the poor visibility due to the smoke that was in theWorcester Cold Storage Warehouse fire inWorcester, Massachusetts was the reason why the trapped rescue firefighters could not evacuate the building in time. Because of the striking similarity that each floor shared, the dense smoke caused the firefighters to become disoriented.[29]
Smoke can contain a wide variety of chemicals, many of them aggressive in nature. Examples arehydrochloric acid andhydrobromic acid, produced fromhalogen-containingplastics andfire retardants,hydrofluoric acid released bypyrolysis offluorocarbonfire suppression agents,sulfuric acid from burning ofsulfur-containing materials,nitric acid from high-temperature fires wherenitrous oxide gets formed,phosphoric acid andantimony compounds from P and Sb based fire retardants, and many others. Suchcorrosion is not significant for structural materials, but delicate structures, especiallymicroelectronics, are strongly affected. Corrosion ofcircuit board traces, penetration of aggressive chemicals through the casings of parts, and other effects can cause an immediate or gradual deterioration of parameters or even premature (and often delayed, as the corrosion can progress over long time) failure of equipment subjected to smoke. Many smoke components are alsoelectrically conductive; deposition of a conductive layer on the circuits can causecrosstalks and other deteriorations of the operating parameters or even cause short circuits and total failures.Electrical contacts can be affected by corrosion of surfaces, and by deposition ofsoot and other conductive particles or nonconductive layers on or across the contacts. Deposited particles may adversely affect the performance ofoptoelectronics by absorbing or scattering the light beams.[citation needed]
Corrosivity of smoke produced by materials is characterized by the corrosion index (CI), defined as material loss rate (angstrom/minute) per amount of material gasified products (grams) per volume of air (m3). It is measured by exposing strips of metal to flow of combustion products in a test tunnel. Polymers containing halogen andhydrogen (polyvinyl chloride,polyolefins with halogenated additives, etc.) have the highest CI as the corrosive acids are formed directly with water produced by the combustion, polymers containing halogen only (e.g.polytetrafluoroethylene) have lower CI as the formation of acid is limited to reactions with airborne humidity, and halogen-free materials (polyolefins,wood) have the lowest CI.[19] However, some halogen-free materials can also release significant amount of corrosive products.[30]
Smoke damage to electronic equipment can be significantly more extensive than the fire itself.Cable fires are of special concern;low smoke zero halogen materials are preferable for cable insulation.[31]
When smoke comes into contact with the surface of any substance or structure, the chemicals contained in it are transferred to it. The corrosive properties of the chemicals cause the substance or structure to decompose at a rapid rate. Certain materials or structures absorb these chemicals, which is why clothing, unsealed surfaces, potable water, piping, wood, etc., are replaced in most cases of structural fires.[citation needed]
In theUnited Kingdom domestic combustion, especially for industrial uses, is the largest single source ofPM2.5 annually.[39][40] In some towns and cities inNew South Wales, wood smoke may be responsible for 60% of fine particle air pollution in the winter.[41] A year-long sampling campaign in Athens, Greece found a third (31%) of PAH urban air pollution to be caused by wood-burning, roughly as much as that ofdiesel andoil (33%) andgasoline (29%). It also found that wood-burning is responsible for nearly half (43%) of annual PAH lung cancer-risk compared to the other sources and that wintertime PAH levels were 7 times higher than in other seasons, presumably due to an increased use offireplaces and heaters. The largest exposure events are periods during the winter with reduced atmospheric dispersion to dilute the accumulated pollution, in particular due to the lowwind speeds.[37] Research conducted about biomass burning in 2015, estimated that 38% of European total particulate pollution emissions are composed of domestic wood burning.[42]
Wood smoke (for example fromwildfires or wood ovens) can cause lung damage,[43][44] artery damage and DNA damage[45] leading to cancer,[46][47] other respiratory and lung disease and cardiovascular disease.[41][48] Air pollution, particulate matter and wood smoke may also cause brain damage because of particulates breaching the cardiovascular system and into the brain,[49][50][51][52] which can increase the risk of developmental disorders,[53][54][55][56] neurodegenerative disorders[57][58] mental disorders,[59][60][61] and suicidal behavior,[59][61] although studies on the link betweendepression and some air pollutants are not consistent.[62] At least one study has identified "the abundant presence in the human brain of magnetite nanoparticles that match precisely the high-temperature magnetite nanospheres, formed by combustion and/or friction-derived heating, which are prolific in urban, airborne particulate matter (PM)."[63] Air pollution has also been linked to a range of other psychosocial problems.[60]
As early as the 15th centuryLeonardo da Vinci commented at length on the difficulty of assessing smoke, and distinguished betweenblack smoke (carbonized particles) and white 'smoke' which is not a smoke at all but merely a suspension of harmless water particulates.[64]
Smoke from heating appliances is commonly measured in one of the following ways:
In-line capture. A smoke sample is simply sucked through a filter which is weighed before and after the test and the mass of smoke found. This is the simplest and probably the most accurate method, but can only be used where the smoke concentration is slight, as the filter can quickly become blocked.[65]
TheASTM smoke pump is a simple and widely used method of in-line capture where a measured volume of smoke is pulled through a filter paper and the dark spot so formed is compared with a standard.
Filter/dilution tunnel. A smoke sample is drawn through a tube where it is diluted with air, the resulting smoke/air mixture is then pulled through a filter and weighed. This is the internationally recognized method of measuring smoke fromcombustion.[66]
Electrostatic precipitation. The smoke is passed through an array of metal tubes which contain suspended wires. A (huge) electrical potential is applied across the tubes and wires so that the smoke particles become charged and are attracted to the sides of the tubes. This method can over-read by capturing harmless condensates, or under-read due to the insulating effect of the smoke. However, it is the necessary method for assessing volumes of smoke too great to be forced through a filter, i.e., frombituminous coal.
Ringelmann scale. A measure of smoke color. Invented by ProfessorMaximilian Ringelmann in Paris in 1888, it is essentially a card with squares of black, white and shades of gray which is held up and the comparative grayness of the smoke judged. Highly dependent on light conditions and the skill of the observer it allocates a grayness number from 0 (white) to 5 (black) which has only a passing relationship to the actual quantity of smoke. Nonetheless, the simplicity of the Ringelmann scale means that it has been adopted as a standard in many countries.
Optical scattering. A light beam is passed through the smoke. A light detector is situated at an angle to the light source, typically at 90°, so that it receives only light reflected from passing particles. A measurement is made of the light received which will be higher as the concentration of smoke particles becomes higher.
Optical obscuration. A light beam is passed through the smoke and a detector opposite measures the light. The more smoke particles are present between the two, the less light will be measured.
Combined optical methods. There are various proprietary optical smoke measurement devices such as the 'nephelometer' or the 'aethalometer' which use several different optical methods, including more than one wavelength of light, inside a single instrument and apply an algorithm to give a good estimate of smoke. It has been claimed that these devices can differentiate types of smoke and so their probable source can be inferred, though this is disputed.[67]
Inference fromcarbon monoxide. Smoke is incompletely burnedfuel, carbon monoxide is incompletely burned carbon, therefore it has long been assumed that measurement of CO influe gas (a cheap, simple and very accurate procedure) will provide a good indication of the levels of smoke. Indeed, several jurisdictions use CO measurement as the basis ofsmoke control. However it is far from clear how accurate the correspondence is.
Historically, people used the smoke ofmedicinal plants to try to cure illness. A sculpture fromPersepolis showsDarius the Great (522–486 BC), the king ofPersia, with twocensers in front of him for burningPeganum harmala and/orsandalwoodSantalum album, which was believed to protect the king from evil and disease. Around the end of the 20th century more than 300 plant species in 5 continents were used in smoke form for different diseases. As a method ofdrug administration, smoking is a simple, inexpensive, but very effective method of extracting particles containing active agents. More importantly, generating smoke reduces the particle size to a microscopic scale thereby increasing the absorption of its active chemical principles. However, as of the early 21st century, thistraditional use has been little studied by modern medicine.[68]
^Stewart, Gareth J.; Nelson, Beth S.; Acton, W. Joe F.; Vaughan, Adam R.; Farren, Naomi J.; Hopkins, James R.; Ward, Martyn W.; Swift, Stefan J.; Arya, Rahul; Mondal, Arnab; Jangirh, Ritu; Ahlawat, Sakshi; Yadav, Lokesh; Sharma, Sudhir K.; Yunus, Siti S. M.; Hewitt, C. Nicholas; Nemitz, Eiko; Mullinger, Neil; Gadi, Ranu; Sahu, Lokesh K.; Tripathi, Nidhi; Rickard, Andrew R.; Lee, James D.; Mandal, Tuhin K.; Hamilton, Jacqueline F. (18 February 2021)."Emissions of intermediate-volatility and semi-volatile organic compounds from domestic fuels used in Delhi, India".Atmospheric Chemistry and Physics.21 (4):2407–2426.Bibcode:2021ACP....21.2407S.doi:10.5194/acp-21-2407-2021.
^Oldfield, F.; Tolonen, K. & Thompson, R. (1981). "History of Particulate Atmospheric Pollution from Magnetic Measurements in Dated Finnish Peat Profiles".Ambio.10 (4): 185.JSTOR4312673.
^Danielsen, Pernille Høgh; Møller, Peter; Jensen, Keld Alstrup; Sharma, Anoop Kumar; Wallin, Håkan; Bossi, Rossana; Autrup, Herman; Mølhave, Lars; Ravanat, Jean-Luc; Briedé, Jacob Jan; de Kok, Theo Martinus; Loft, Steffen (18 February 2011). "Oxidative Stress, DNA Damage, and Inflammation Induced by Ambient Air and Wood Smoke Particulate Matter in Human A549 and THP-1 Cell Lines".Chemical Research in Toxicology.24 (2):168–184.doi:10.1021/tx100407m.PMID21235221.S2CID11668269.
^Navarro, Kathleen M.; Kleinman, Michael T.; Mackay, Chris E.; Reinhardt, Timothy E.; Balmes, John R.; Broyles, George A.; Ottmar, Roger D.; Naher, Luke P.; Domitrovich, Joseph W. (June 2019). "Wildland firefighter smoke exposure and risk of lung cancer and cardiovascular disease mortality".Environmental Research.173:462–468.Bibcode:2019ER....173..462N.doi:10.1016/j.envres.2019.03.060.PMID30981117.S2CID108987257.
^Flores-Pajot, Marie-Claire; Ofner, Marianna; Do, Minh T.; Lavigne, Eric; Villeneuve, Paul J. (November 2016). "Childhood autism spectrum disorders and exposure to nitrogen dioxide, and particulate matter air pollution: A review and meta-analysis".Environmental Research.151:763–776.Bibcode:2016ER....151..763F.doi:10.1016/j.envres.2016.07.030.PMID27609410.
^Fu, Pengfei; Yung, Ken Kin Lam (15 September 2020). "Air Pollution and Alzheimer's Disease: A Systematic Review and Meta-Analysis".Journal of Alzheimer's Disease.77 (2):701–714.doi:10.3233/JAD-200483.PMID32741830.S2CID220942039.
^Tsai, Tsung-Lin; Lin, Yu-Ting; Hwang, Bing-Fang; Nakayama, Shoji F.; Tsai, Chon-Haw; Sun, Xian-Liang; Ma, Chaochen; Jung, Chau-Ren (October 2019). "Fine particulate matter is a potential determinant of Alzheimer's disease: A systemic review and meta-analysis".Environmental Research.177 108638.Bibcode:2019ER....17708638T.doi:10.1016/j.envres.2019.108638.PMID31421449.S2CID201057595.
^abLiu, Qisijing; Wang, Wanzhou; Gu, Xuelin; Deng, Furong; Wang, Xueqin; Lin, Hualiang; Guo, Xinbiao; Wu, Shaowei (February 2021). "Association between particulate matter air pollution and risk of depression and suicide: a systematic review and meta-analysis".Environmental Science and Pollution Research.28 (8):9029–9049.Bibcode:2021ESPR...28.9029L.doi:10.1007/s11356-021-12357-3.PMID33481201.S2CID231677095.
