ASK THE METEOROLOGIST
“What does the term ‘acid rain’ mean?”
4th/5th Grade, Vineyard Christian School
Acid rain is rain that is unusually acidic. In other words, it has high levels of hydrogen ions. Other forms of precipitation, in addition to rain, can be acidic. Freezing rain and snow being two examples.
Acid precipitation can be harmful to plant life, pollute rivers and streams, peel paint and do damage to buildings/infrastructure. Statues and bridges can be damaged from acid precipitation.
In order for this to happen, sulfur dioxide and nitrogen oxide must be present in the atmosphere. So how do we get these gases in our atmosphere? Both of them can be put into our atmosphere from 1. human activity and 2. naturally occurring processes on Earth.
Sulfure dioxide can be emitted into the atmosphere through industrial processes at refineries and power plants but also through volcanic eruptions. Nitrogren oxide, similarly is released into the atmosphere from industrial facilities but also from lightning.
When these compounds are emitted into the atmosphere, they stay present as gases. If there is enough moisture present, these gases will combine with that moisture to form a cloud droplet which would then be acidic. From this cloud, acidic precipitation would fall, if once again, enough moisture is present.