Whatever happened to acid rain?

[Richard]

Originally Posted by spadlet

Isn't acid rain another of the contributors to the acidification of the oceans?

I'm not entirely sure but wouldn't think so, at least not on a global scale. Probably more to do with rising CO2 levels and production of carbonic acid. I think acid rain was more of a local/regional land based problem.

[Cricket Tragic]

Originally Posted by spadlet

Isn't acid rain another of the contributors to the acidification of the oceans?

Given the large size of the oceans, the significant buffering capacity of the oceans and the relative pH difference between acid rain and oceans, I suggets not. The worst effects of acid rain tend to be in small water bodies.

CO2 dissolves in water to produce carbonic acid and normal rain has a pH between 5.7 and 6 (depending on what else is in there). Increasing the partial pressure of CO2 above a solution of pure water from current atmospheric to 3 times that amount, will decrease the pH from 5.7 to about 5.4.

[forfismum]

A recent bit on ocean acidity

News and Communication Services at Oregon State University

[MarkuisMellvile]

Originally Posted by Windguy

Sulphur scrubbers were installed in nearly all coal fired power plants in the late 70's in western society.

Richard is correct to say that the dash for gas in the 1980s had an effect on the sulphur emitted by our power stations in the UK, but we certainly don't make as much use of Flue Gas Desulphurisation (FGD) as Windguy suggests and the acidification of Scandanavian and British waterways was increasing well into the 1980s.

Privatised British power companies haven't invested in FGD, unlike the state run German utility did at the time. RWE have benefitted from German Government installation of FGD on all German coal-fired plant, whereas we only have a handful of FGD fitted power stations in the UK.

And guess what....because power from these is more expensive than the bulk of our coal-fired plant, we only use the FGD equipped power stations when our peak power demand is reached. The rest of the time we only use the dirtier (non-FGD) power stations that sell cheaper electricity.

That Acid Rain is low on the public agenda these days does not mean the problem has gone away, just that the media has a short attention span and other issues sell papers and air-time these days.

MM

[Windguy]

Emissions

Sulfur dioxide emissions from the Halema`uma`u vent, glows at nightAccording to the U.S. EPA (as presented by the 2002 World Almanac or in chart form[9]), the following amount of sulfur dioxide was released in the U.S. per year, measured in thousands of short tons:

*1999 18,867
*1998 19,491
*1997 19,363
*1996 18,859
*1990 23,678
*1980 25,905
*1970 31,161

Due largely to the US EPA’s Acid Rain Program, the U.S. has witnessed a 33 percent decrease in emissions between 1983 and 2002. This improvement resulted from flue gas desulfurization, a technology that enables SO2 to be chemically bound in power plants burning sulfur-containing coal or oil. In particular, calcium oxide (lime) reacts with sulfur dioxide to form calcium sulfite:

CaO + SO2 → CaSO3
Aerobic oxidation converts this CaSO3 into CaSO4, gypsum. Most gypsum sold in Europe comes from flue gas desulfurization.

New fuel additive catalysts, such as ferox, are being used in gasoline and diesel engines in order to lower the emission of sulfur oxide gases into the atmosphere. This is also done by forcing the sulfur into stable mineral salts and mixed mineral sulfates as opposed to sulfuric acid and sulfur oxides.

As of 2006, China is the world's largest sulfur dioxide polluter, with 2005 emissions estimated to be 25.49 million tons. This amount represents a 27% increase since 2000, and is roughly comparable with U.S. emissions in 1980[10].

Al-Mishraq, an Iraqi sulfur plant, was the site of a 2003 disaster resulting in the release of massive amounts of sulfur dioxide into the atmosphere.

So at least some of the western world is doing their bit and gaining a byproduct to sell.

One idea is for CO2 scrubbers in the future that produce bi-carb soda. The problem is you produce about 2 to 2.5 tons of bicarb for every ton of CO2.

[forfismum]

Toxic sofas,whatever next to excite the masses.

Argos to be sued after toxic sofas blamed for causing skin burns and allergies - Telegraph

[forfismum]

OK here's the question.If the volume of mercury emitted was overlooked,what else has been missed?

Volcano ‘pollution’ solves mercury mystery - University of Oxford

[Robert Northup]

Whatever Happened to “Acid Rain”?

The field of biogeochemistry was born from the need for an interdisciplinary approach to understanding the ecological consequences of acidic deposition (a.k.a. “acid rain”). Large-scale damage was observed in forests of northern Europe and the north eastern part North America. The primary acidic ingredient in “acid rain” was sulfuric acid. The predominant source was sulfur in fossil fuel, and the worst damage occurred down wind from power plants burning sulfur-rich coal or fuel oil. After much debate and many delays, effective measures were taken to reduce sulfur emissions. The worst “acid rain” problem was solved, sort of.

Even in the heyday of sulfuric emissions, “acid rain” also included nitric acid. In many parts of the world, the nitric acid content is significantly greater than the sulfuric acid content. And anywhere in the world, even with the purest rainfall in the most remote site, carbon dioxide makes all rainfall slightly acidic. In fact, rainfall is measurably more acidic now than it was when people began making precise pH measurements, because the concentration of carbon dioxide in the atmosphere has increased. Without nitric acid or sulfuric acid (both of predominantly anthropogenic origin), the atmospheric carbon dioxide, in equilibrium with the rain drops, produces enough carbonic acid to give pure, natural rain fall a pH of about 5.5. With anthropogenic emissions of sulfuric acid and nitric acid added to it, rain fall pH near 4 was not unusual.

The forests where “acid rain” did its worst damage grew on soils that were already naturally acidic, and somewhat deficient in calcium and magnesium. The symptoms of widespread tree damage included aluminum toxicity, and or deficiency of calcium and/or magnesium. As the sulfuric acid, nitric acid, and carbonic acid in rain fall wash through the soil, they leave their acidic protons (hydrogen ions) behind. As the leftover sulfate, nitrate, and bicarbonate wash on through, they drag along calcium, magnesium, and aluminum with them. Fish in poorly buffered lakes were harmed by the aluminum sulfate entering through seepage water. The natural acid neutralizing capacity of the soils were depleted, and the natural mechanisms that mitigated aluminum toxicity were impeded. Large scale lime application was attempted in many forested areas, to neutralize acidity and replace lost calcium.

[Robert Northup]

An important part of solving the acid rain problem was to reduce sulfur emissions. Sulfuric acid is more aggressive than nitric acid or carbonic acid, because sulfate is much more capable of dragging calcium, magnesium, or aluminum with it, depleting soil nutrients and poisoning the lakes. However, another component of “acid rain” is nitric acid, and this proved to be a more insidious long-term problem A whole lot of human activities ultimately result in the emissions of nitrogen compounds that oxidize to nitric acid. Nitric acid contains nitrate, which is a bioavailable form of nitrogen for plants and microorganisms, and nitrate is also an oxidant that can be used by microorganisms. The initial impact of nitric acid was to act as a nutrient. Nitrogen is usually a limiting nutrient in most ecosystems, and the result of increased bioavailable nitrogen is usually increased biomass and increased productivity (carbon captured by photosynthesis, etc.). However, too much of a good thing is not good. The geographic range of forests showing damage from “acid rain” has expanded dramatically, impacting about an order of magnitude larger area, since the days when the “acid rain” problem gave birth to my field of study (and my first research assistant position at Berkeley). However, the new forest damage looks a lot different the problem that first got our attention. The problem now is nitrogen “saturation”. Ecosystems now receive greater inputs of nitrogen in rain fall than they can effectively absorb. Excess nitrogen has been causing nutrient loading to surface waters, among other problems.

Good old fashioned sulfuric acid rain may be forgotten, but not gone. Industrialized nations may have reduced their sulfur emissions, but there is plenty of sulfur-rich fossil fuel now being burned in other nations. Nitric acid rain won’t go away either, unless we do something about anthropogenic emissions.

[EarthPro]

I wonder if when I am say, thirty years old(21 currently) if global warming will be all but forgotten about.