1. Acid Rain!!

2. How does acid rain affect stonework?
The picture on the left was taken in 1908…
The picture on the right was taken in 1968!

3. Acid rain is more acidic than normal rain and forms through a complex process of chemical reactions involving air pollution.
The two most important pollutants that contribute to acid rain are sulfur dioxide and nitrogen oxides, which react with moisture in the atmosphere forming acid rain.
The sulfur and nitrogen compounds  primarily come from human sources, such as automobiles, industries and utilities.
Acid rain can have many disguises…It can fall as snow, hail, sleet, or fog.

4. pH strips allow you to test different liquids to see how acidic or basic they are. Tap water is usually about a 7 or neutral on the pH scale.

5. Acid rain can harm forests and crops by washing away nutrients and poisoning the plants.
Bodies of water can have their pH altered so much that the aquatic life dies, or different, more acid tolerant, species take over.
The corners of buildings can be slowly be eaten away, and statues can be smoothed as ears, noses, and any other parts that stick out are slowly dissolved.
Don't panic! Acid rain is not a strong enough acid to do you harm as it lands on your skin. Acid rain usually has a pH of about
Remember pure water has a pH of 7.
If we compare acid rain to other everyday items we can see that it is not as acidic as a lemon (pH 2.2) or even an apple (ph 3.0).

6. This figure illustrates the pH level at which key organisms may be lost as their environment becomes more acidic.

7. Acid rain meets limestone in the ground (Especially in our area where limestone is plentiful). This has TWO effects:
The acid rain is starting to destroy and slowly break down the limestone
The limestone is actually a natural base. So… when the acid rain hits the limestone, it is actually helping to NEUTRALIZE that acid rain water before it reaches a major water source. It isn’t a perfect system, but it is natures best way of fixing the problem!