Knowra Acid rain Acid rain Acid rain is precipitation made unusually acidic by airborne pollutants, especially sulfur dioxide and nitrogen oxides that form sulfuric and nitric acids.
Sulfur dioxide : A colorless, pungent gas produced mainly by burning sulfur-containing fuels and processing sulfur ores. Atmospheric oxidation of this pollutant produces sulfuric acid in acid rain.
Freshwater acidification : A decline in the pH of lakes, streams, or other freshwater systems due to acidic inputs. Acid rain can lower water pH and threaten aquatic organisms.
Coal-fired power station : A power plant that generates electricity by burning coal to produce steam and drive turbines. Coal combustion releases sulfur dioxide, a major precursor of acid rain.
pH : A logarithmic measure of hydrogen-ion activity used to describe how acidic or alkaline a solution is. Precipitation pH quantifies acidity, though it does not by itself identify its source.
Carbon dioxide : A colorless gas produced by respiration, combustion, and other processes, and a major greenhouse gas. Dissolved carbon dioxide makes ordinary rain mildly acidic, unlike the stronger acidity driven by sulfuric and nitric acids.
Nitrogen oxides : Reactive gases composed of nitrogen and oxygen, including nitric oxide and nitrogen dioxide. These combustion pollutants form nitric acid through atmospheric reactions.
Soil acidification : A decline in soil pH caused by acidic inputs and changes in soil chemistry. Acid deposition can leach nutrients and mobilize toxic metals in soils.
Vehicle emissions : Gases and particles released by motor vehicles during fuel combustion and operation. Nitrogen oxides from engines contribute to nitric acid formation.
Acid deposition monitoring : The systematic measurement of acidity and chemical composition in precipitation and deposited pollutants. Monitoring reveals where acid deposition occurs and how its chemistry changes over time.
Ocean acidification : The long-term decrease in ocean pH, primarily caused by seawater absorbing atmospheric carbon dioxide. It is a distinct acidification problem driven chiefly by carbon dioxide, not acid rain.
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