Data And Facts

Technically, all rain is acidic. Regular rain has a pH ranging above 5.0. “Acid” rain, however, has a pH ranging around 4.0
What makes rain become acid rain is caused by fossil fuels, especially sulfur dioxide and nitrogen. 
In 1970, the “Clean Air Act” was created to regulate and cut down on toxic emissions, and then later tightened those regulations in 1990. This ended up cutting down the rises in sulfate and nitrate chemicals in precipitation by about 40%. 
It is estimated that acid rain causes about 550 human deaths per year.