ACID RAIN
The deposition of acidic components in wet forms such as fog, snow or hail and in dry forms such as acidic particles from the atmosphere is called acid rain.
Major reason is:-
- Acid rain results when sulphur dioxide (SO2) and nitrogen oxides (NOX) already present in the atmosphere react with water, oxygen and other chemicals to make sulphuric and nitric acids.
- While a littleportion of acid precipitation is contributed from natural sources such as volcanoes, most of it comes from the burning of fossil fuels.
The major sources of SO2 and NOX within the atmosphere are:

Pathway of acid rain:

Forms of Acid Deposition
Wet Deposition
- Wet deposition is what we most ordinarily consider as acid precipitation
- The sulphuric and nitric acids fall to the ground with rain, snow, fog, or hail.
dry Deposition
- When acid particles deposit on in the absence of moisture we called this as dry deposition.
- The acidic particles deposited on the surfaces may react during atmospheric transport to make larger particles which will be harmful to human health.
- These particles get washed off by second rain and flows through the ground harming the plants, vegetation, wildlife like fishes
MEASURING ACID RAIN
pH range of Acid rain = 4.2 and 4.4

EFFECTS OF ACID RAIN ON HUMAN COMMUNITIES AND AGRICUTURE
1. Human Health
- It causes respiratory issues in living beings.
- When fine sulphate and nitrate particle came in contact with humans or inhaled by them, than these effects the heart function such as heart attacks resulting in death for people with increased heart condition risk, and effects on lung function, like breathing difficulties for people with asthma.
2. Agriculture
- Acid precipitation is extremely harmful to agriculture, and plants. It washes away all nutrients required for the expansion and survival of plants.
- Acid rain affects agriculture as it alters the composition of the soil.
OTHER IMPACTS
- When acid precipitation falls down and flows into the rivers and ponds it affects the aquatic ecosystem. As it alters the chemical composition of the water, to a form which is harmful to the aquatic ecosystem to survive and causes H2O pollution
- Acid precipitation also causes the corrosion of water pipes. Which further leads to leaching of heavy metals such as iron, lead and copper into water
- It damages the buildings and monuments made from stones and metals.
Examples:
- Taj Mahal, one among the 7 wonders, is largely affected by acid precipitation. Reason: presence of industries, in Agra, which emit oxides of sulphur and nitrogen in the atmosphere
- Statue of Liberty which is formed of copper has also been damaged by the cumulative action of acid rain & oxidation for over 30 years and is, therefore, becoming green.