User:Bohne086/Sulfate aerosol

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Sulfate aerosols are suspensions of fine solid particles of a sulfate or tiny droplets of a solution of a sulfate or of sulfuric acid (hydrogen sulfate). They are produced by chemical reactions in the atmosphere from gaseous precursors (with the exception of sea salt sulfate and gypsum dust particles). The two main sulfuric acid precursors are sulfur dioxide (SO2) from anthropogenic sources and volcanoes, and dimethyl sulfide (DMS) from biogenic sources, especially marine plankton. These aerosols can impact climate change by causing a cooling effect on earth through the reduction of incoming solar radiation to the surface of the earth through reflection, and the idea of using these as a human-induced climate change mitigation tool by releasing them into the atmosphere purposefully has been mentioned. The study of sulfate aerosols has led to the overall conclusion that they essentially behave as cloud condensation nuclei which alters cloud properties in the atmosphere and tends to increase the albedo of them which cools the climate and could theoretically alleviate some global warming effects through geoengineering due to more reflection of insolation and less shortwave solar radiation absorbed at the surface.

Properties
Sulfate aerosols are particulate matter suspended in the atmosphere made of sulfur compounds. Sulfate aerosols are typically produced either directly from sulfur dioxide or sulfur gases transitioning through chemical reactions in the atmosphere with compounds residing there or sulfur dioxide being oxidized in clouds in which sulfuric acid forms leaving sulfate particles upon evaporation. Reactions involved in the process of making sulfate aerosols are sulfur dioxide and DMS using water vapor to create gaseous sulfuric acid which makes fine particles and can then form salts; another reaction would be when sulfur dioxide dissolves into cloud droplets and is oxidized into sulfuric acid and salts which can then evaporate and precipitate sulfate aerosols. The forms of sulfate aerosols in the atmosphere can include inorganic sulfate which is SO42- and HSO4- as well as H2SO4- in which these compounds can make up a large amount of the fine particulate matter in the environment that is under or equal to 2.5 micrometers in diameter; organic sulfur components can also be considered in this sector. With the properties that sulfate aerosols have, they often act as cloud condensation nuclei which attracts water impacting light scattering, and they can also deplete the ozone layer in the stratosphere through acting as a surface that ozone-depleting substances thrive on.

Origins
There are many origins of sulfate aerosols including anthropogenic, biogenic from hydrosphere, lithosphere, and biosphere, and natural sources such as volcanoes or burning. Some of the anthropogenic sources of sulfate aerosols, which may be the leading source, include the combustion or burning of fossil fuels (specifically oil and coal). Biological sources include DMS from marine phytoplankton which is the "main natural carrier of reactive sulfur" and produces sulfuric acid using water vapor or can form MSA. After volcanic eruptions, injected water vapor converts injected sulfur dioxide to sulfate aerosols in the stratosphere to create sulfate aerosol plumes; one pathway that the production of sulfate aerosols is thought to take is to grow during the processes of hygroscopic growth and coagulation and then shrink through evaporation. One of the smallest natural sources of sulfur in the atmosphere that can lead to sulfate aerosols is from swamps and other lands of the sort.

Effects
Sulfate aerosols scatter and reflect insolation which, overall, has a negative radiative forcing effect and cools the surface by not letting as much incoming solar radiation reach it. The lifetime of them in the atmosphere is only a few days to less than a week, but during this time they make more reflective clouds form for a longer period of time; they increase the amount of cloud droplets while simultaneously decreasing the size of the cloud droplets which causes the higher albedo and less absorbed incoming shortwave radiation from the sun at the surface which contributes to the overall cooling effect that may counteract global warming effects. Sulfate aerosols deplete ozone concentrations due to perturbations in photolysis rates, acting as a surface that compounds with high ozone-depleting potential react on, and more. Another effect is acid rain which is detrimental to the health of various different ecosystems across the planet as the precipitation that comes from these clouds is acidic from using the aerosols as cloud condensation nuclei. The release of sulfate aerosols has benefits and disadvantages on the health of humanity due to them existing as irritants and other associated health risks and the environmental effects they can have on climate change and such.

Scientific Study
Some of the methods used to study sulfate aerosols and atmospheric chemical composition of them include ion-chromatography, mass spectrometry, and remote satellites. Potential climate change mitigation strategies using sulfate aerosols or their precursors have been suggested; one of these strategies is geoengineering through injection of sulfate aerosols into the stratosphere since they have a net cooling effect from scattering of insolation. There are possible cons to consider with this methodology such as depletion of the ozone layer, climate risks such as more heating in different parts of the atmosphere than what is considered natural, and atmospheric composition adjustments to these perturbations. There are still uncertainties about sulfate aerosols to consider regarding the quantification of radiative forcing and assessment of environmental impacts such as climate change. For example, the magnitude of the effect of forcing from aerosols by decreasing insolation received at the surface is still uncertain particularly when considering a model and complex calculations due to different confounding factors and parameters such as optical properties, spatial and temporal distribution of emission or injection, albedo, geography, loading, rate of transport of sulfate, global burden, atmospheric chemistry, mixing and reactions with other compounds and aerosols, particle size, relative humidity, and clouds. Along with others, aerosol size distribution and hygroscopicity have particularly high uncertainty due to being closely related to sulfate aerosol interactions with other aerosols which affects the amount of radiation reflected.