Sulfate

[3][4] A widely accepted description involving pπ – dπ bonding was initially proposed by Durward William John Cruickshank.

[6] In this model, the structure obeys the octet rule and the charge distribution is in agreement with the electronegativity of the atoms.

However, Pauling's representation for sulfate and other main group compounds with oxygen is still a common way of representing the bonding in many textbooks.

Alum, a double sulfate of potassium and aluminium with the formula K2Al2(SO4)4·24H2O, figured in the development of the chemical industry.

Sulfates occur as microscopic particles (aerosols) resulting from fossil fuel and biomass combustion.

The anaerobic sulfate-reducing bacteria Desulfovibrio desulfuricans and D. vulgaris can remove the black sulfate crust that often tarnishes buildings.

[19][20][21][22][23] This followed measures taken to combat air pollution by the developed nations, typically through flue-gas desulfurization installations at thermal power plants, such as wet scrubbers or fluidized bed combustion.

[24][25][26] In the United States, sulfate aerosols have declined significantly since 1970 with the passage of the Clean Air Act, which was strengthened in 1977 and 1990.

[27] By 2010, this reduction in sulfate pollution led to estimated healthcare cost savings valued at $50 billion annually.

[29] Since changes in aerosol concentrations already have an impact on the global climate, they would necessarily influence future projections as well.

In fact, it is impossible to fully estimate the warming impact of all greenhouse gases without accounting for the counteracting cooling from aerosols.

[35] On regional and global scale, air pollution can affect the water cycle, in a manner similar to some natural processes.

[43] Likewise, it has been suggested since the early 2000s that since aerosols decrease solar radiation over the ocean and hence reduce evaporation from it, they would be "spinning down the hydrological cycle of the planet.

The structure and bonding of the sulfate ion. The distance between the sulfur atom and an oxygen atom is 149 picometers.
Ball-and-stick model of the sulfate anion
Two models of the sulfate ion.
1 with polar covalent bonds only; 2 with an ionic bond
Six resonances
Knapsack sprayer used to apply sulfate to vegetables. Valencian Museum of Ethnology .
This figure shows the level of agreement between a climate model driven by five factors and the historical temperature record . The negative component identified as "sulfate" is associated with the aerosol emissions blamed for global dimming.
The observed trends of global dimming and brightening in four major geographic regions. The dimming was greater on the average cloud-free days (red line) than on the average of all days (purple line), strongly suggesting that sulfate aerosols were the cause. [ 10 ]
Sulfur dioxide in the world on April 15, 2017. Note that sulfur dioxide moves through the atmosphere with prevailing winds and thus local sulfur dioxide distributions vary day to day with weather patterns and seasonality.
Sun-blocking aerosols around the world steadily declined (red line) since the 1991 eruption of Mount Pinatubo , according to satellite estimates.
Satellite photo showing a thick pall of smoke and haze from forest fires in Eastern China . Such smoke is full of black carbon, which contributes to dimming trends but has an overall warming effect.
Sulfate aerosols have decreased precipitation over most of Asia (red), but increased it over some parts of Central Asia (blue). [ 42 ]
In the United States, aerosols generally reduce both mean and extreme precipitation across all four seasons, which has cancelled out the increases caused by greenhouse gas warming [ 46 ]
refer to caption and image description
Proposed tethered balloon to inject aerosols into the stratosphere.
Hydrogen sulfate (bisulfate)