Acid rain, or acid deposition, is a broad term that includes any form of precipitation with acidic components, such as sulfuric or nitric acid that fall to the ground from the atmosphere in wet or dry forms.

The ecological effects of acid rain are most clearly seen in aquatic environments, such as streams, lakes, and marshes where it can be harmful to fish and other wildlife.

The Acid Rain Program (ARP), established under Title IV of the 1990 Clean Air Act (CAA) Amendments requires major emission reductions of sulfur dioxide (SO2) and nitrogen oxides (NOx), the primary precursors of acid rain, from the power sector. 

An educational tool to help parents and children learn more about acid rain.

Read about how Lucy Lake and her friends learn about acid rain and how to prevent it.

Test your knowledge of facts about acid rain!

This book is intended for teachers of students in 6th-8th grade. 

The Plain English Guide to the Clean Air Act provides a brief introduction to the 1990 Clean Air Act.

The Earth’s ozone layer protects all life from the sun’s harmful radiation, but human activities have damaged this shield.

Reduced ozone levels as a result of ozone depletion mean less protection from the sun’s rays and more exposure to UVB radiation at the Earth’s surface.

This page provides information on compounds recognized as ozone-depleting substances (ODS) under the Montreal Protocol.

The Atmospheric and Health Effects Framework (AHEF) model is used by the EPA to evaluate human health effects associated with a depleted stratospheric ozone layer.

As part of the United States’ commitment to implementing the Montreal Protocol on Substances that Deplete the Ozone Layer, Congress amended the Clean Air Act to add provisions (under Title VI) for protecting the ozone layer.

In our nation’s scenic areas, the visual range has been substantially reduced by air pollution.

In 1999, the U.S. Environmental Protection Agency announced a major effort to improve air quality in national parks and wilderness areas.

Understanding and addressing climate change is critical to EPA’s mission of protecting human health and the environment.

Between 2018 and 2019, greenhouse gas emissions decreased 1.7%, primarily because of a drop in fossil fuel combustion emissions, which was largely due to trends in the electric power sector.

Gases that trap heat in the atmosphere are called greenhouse gases.

Did you ever wonder what reducing carbon dioxide (CO2) emissions by 1 million metric tons means in everyday terms?

EPA partners with more than 40 data contributors from various government agencies, academic institutions, and other organizations to compile a key set of indicators related to the causes and effects of climate change.