How do sulfur dioxide and nitrogen oxide emissions cause acid rain?

Acid rain is caused by emissions of sulfur dioxide and nitrogen oxide reacting with water molecules in the atmosphere to produce sulfuric and nitric acids. This precipitation features an unusually low pH, which can damage forests, aquatic life, and infrastructure. While the primary sources of these chemical compounds are anthropogenic, natural events like volcanic eruptions and lightning strikes also contribute.

What we know

• Acid rain is caused by emissions of sulfur dioxide and nitrogen oxide, which react with water molecules in the atmosphere to produce sulfuric and nitric acids. [3]
• The main source of sulfur and nitrogen compounds resulting in acid rain are anthropogenic, but nitrogen oxides can also be produced naturally by lightning strikes and sulfur dioxide by volcanic eruptions. [3]
• Nitrogen dioxide is included in the NOx family of atmospheric pollutants and is produced by combustion processes. [2, 4]

Where to go next

• what followedWhat are the primary ecological effects of acid rain?
• how it workedHow do industrial combustion processes form nitrogen oxides?
• how we knowWhich laws regulate sulfur and nitrogen emissions?
• a case in pointWhat is nitrogen dioxide and how does it impact indoor air?
• the bigger pictureWhat role does sulfur play in biological systems?
• an unexpected connectionHow does a signaling molecule in the body relate to acid rain pollutants?Nitric oxide, a primary nitrogen oxide involved in forming acid rain, also functions as an important cardiovascular signaling molecule in mammals.

Sources

• [1]nitrogen dioxide (Wikidata Q207895) · CC0 1.0
• [2]Nitrogen dioxide · CC BY-SA 4.0
• [3]Acid rain · CC BY-SA 4.0
• [4]Nitric oxide · CC BY-SA 4.0
• [5]Sulfur · CC BY-SA 4.0