Air, Animals and Plants

Air, Animals, and Plants, Thursday, May 8th

Air pollution impacts animals and plants through a variety of pathways — directly through the air and indirectly through the water and soil.  Air Quality Awareness Week is a great time learn about how air pollution impacts our ecosystems and the work that EPA is doing to protect air quality and our ecosystems. 

On this page:

Air, Animals and Plants Basics

What is an ecosystem?

An ecosystem is a community of plants, animals and other organisms, along with their environment, including the air, water and soil. Air pollutants can cause many environmental effects on ecosystems. Everything in an ecosystem is connected. If something harms one part of an ecosystem - one species of plant or animal, the soil or the water - it can have an impact on everything else.

Ecosystem habitats

Aquatic environments such as streams, lakes, marshes, and coastal waters are often impacted by air pollutants. Acid rain, also known as acid deposition, forms from nitrogen, sulfur, and other compounds. Acid rain can damage lakes and streams, impacting the fish and other wildlife within these ecosystems. As it flows through the soil, acidic rainwater can leach aluminum from soil particles, which then flows into streams and lakes. The more acid that is introduced to the ecosystem, the more aluminum is released. Some types of plants and animals are able to tolerate acidic waters and moderate amounts of aluminum. Others, however, are acid-sensitive and will be lost as the pH declines. 

Test Your Knowledge 1

What is the most abundant element in the air?

 

Did You Know?

Nitrogen is an essential nutrient required for all life on Earth and is a key component of cell amino acids, proteins, and DNA. Excess nitrogen can cause algae to grow faster than ecosystems can handle, which can harm water quality, food resources and habitats, and decrease the oxygen that fish and other aquatic life need to survive. 

Learn more:

 

B is the correct answer.

 

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Measuring acid rain

Acidity and alkalinity are measured using a pH scale for which 7.0 is neutral. The lower a substance's pH (less than 7), the more acidic it is and the higher a substance's pH (greater than 7), the more alkaline it is. Normal rain has a pH of about 5.6; it is slightly acidic because carbon dioxide dissolves into it, forming weak carbonic acid. Acid rain usually has a pH between 4.2 and 4.4.  Learn more at EPA's acid rain website.

A list of Critical pH Levels for Aquatic Organisms; details in caption.
The figure illustrates the pH level at which key organisms may be lost as their environment becomes more acidic. The scale ranges from snails and clams at 6 to frogs at 4.
Infographic depicting how acid rain is created and moves through the environment
This image illustrates the pathway for acid rain in our environment: (1) Emissions of SO2 and NOx are released into the air, where (2) the pollutants are transformed into acid particles that may be transported long distances. (3) These acid particles then fall to the Earth as wet and dry deposition (dust, rain, snow, etc.) and (4) may cause harmful effects on soil, forests, streams, and lakes.  

Deposition of nitrogen oxides contributes to the nutrient enrichment (or “eutrophication”) of soils and surface waters. Too much nitrogen and other nutrients, such as phosphorus, in the water causes algae to grow faster than ecosystems can handle. Significant increases in algae harm water quality, food resources and habitats, and decrease the oxygen that fish and other aquatic life need to survive. 

Plants can be damaged directly by air pollutants. When ozone enters the leaves of a sensitive plant, it can reduce photosynthesis, the process by which the plant produces energy needed for growth and repair. This can lead to a slowing of plant growth, reduction in defense against disease and insects, and a loss of below ground root function. Over the long-term, these combined effects can reduce the overall health of a tree, causing it to be replaced by less ozone-sensitive species. This can create changes in habitat quality and nutrient and water cycles. This is especially impactful during the growing season. 

Did you know?

Tropospheric, or ground-level ozone, is not emitted directly into the air, but is created by chemical reactions between oxides of nitrogen (NOx) and volatile organic compounds (VOC). This happens when pollutants emitted by cars, power plants, industrial boilers, refineries, chemical plants, and other sources chemically react in the presence of sunlight.

Ozone is most likely to reach unhealthy levels on hot, sunny days in urban environments, but can still reach high levels during colder months. Ozone can also be transported long distances by wind, so even rural areas can experience high ozone levels. 

Learn more: Ground-level Ozone Basics

Test Your Knowledge 2

Since the start of the Acid Rain Program, annual sulfur dioxide emissions from power plants have dropped by more than:

 

 

D is the correct answer.

Find out more on our website: https://www.epa.gov/power-sector/progress-report

 

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AirKnowledge Learning Corner!

Image of birds in shallow water and the title of the module Environmental Effects of Air Pollution

Complete this module to learn more about air, animals and plants and to understand the environmental effects of air pollutants:

Test Your Knowledge 3

Some toxic air pollutants such as mercury can deposit onto soils or surface waters, where they are taken up by plants and ingested by animals. Which term describes how mercury moves through the food chain?

 

 

B is the correct answer.

 

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Air, Animals and Plants Tools and Activities 

How Does EPA Protect the Environment? Activity Book  

The cover of the how does EPA protect the environment activity book for children

This activity book allows kids to learn about the different ways that EPA works to protect our environment and our health. The activities featured provide an overview of the different ways in which EPA protects human health and the environment.  

Pollinator Protection Activities 

You can help protect pollinators in your community! These educational resources and activities help students, parents, teachers, and consumers learn about pollinators and how to protect them - from pollinator-friendly gardening to responsible management of pests. 

Habitats Interactive Game 

Play the Habitats game! Explore the desert, coral reef, jungle, and marsh to discover where many animals live by matching each animal to their correct habitat. The Habitats game is available as a website for desktop and laptop computers. 

Animals and Plants Activities 

Learn more about animals, plants and the environment through a variety of games and activities: 

Test Your Knowledge 4

Atmospheric deposition of nitrogen and sulfur resulting from air pollution is a major stressor to natural ecosystems, often leading to ___________ of both terrestrial and aquatic ecosystems.

 

 

D is the correct answer.

 

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EPA’s Work on Air, Animals and Plants 

Air Trends Report

For more than 50 years, EPA has maintained its commitment to protecting public health by reducing pollutant emissions and improving air quality. The annual Air Trends Report, titled Our Nation's Air, summarizes the nation's air quality status and trends through 2023. 

Sections of this report convey information across different time periods, depending on the underlying data sources. While some are consistently available since 1970, like growth data, our longer-term trends for air quality concentrations start in 1990, when monitoring methodologies became more consistent. 

View the interactive report today.   

"Air Pollution Sources and Effects" graphic; details in caption
This graphic depicts the sources of air pollution and how it flows through the environment. Includes "emissions" from "stationary", "natural", and "vehicle" that "transport" and create a "chemical reaction" - resulting in "ozone" - in the atmosphere to result in "haze" and "deposition" and results in "health effects."

Health and Environmental Effects of Hazardous Air Pollutants 

In addition to exposure from breathing air toxics, some toxic air pollutants, such as mercury, can deposit onto soils or surface waters, where they are taken up by plants and ingested by animals and are eventually magnified up through the food chain. Like humans, animals may experience health problems if exposed to sufficient quantities of air toxics over time. Learn more about health and environmental effects of hazardous air pollutants.    

Ecosystems and Air Quality Research 

EPA researchers are exploring the dynamic interrelationships between natural ecosystems and air quality — advancing our understanding of how air pollution can negatively impact forests, lakes, and other natural ecosystems and the benefits they provide.

Learn more about how EPA researchers are delivering tools, data, and information necessary to accurately account for ecosystem services in decisions, and to help advance healthy, sustainable, and more prosperous communities visiting EPA's Ecosystems Research website. 

Final Ecosystem Goods and Services (FEGS) Scoping Tool

The FEGS Scoping Tool provides a structured, transparent, and repeatable process for identifying and prioritizing stakeholders, the ways those stakeholders benefit from the environment, and the aspects of the environment necessary to realize those benefits. Explore FEGS today. 

Test Your Knowledge 5

True or False: There is no such thing as "good" ozone.

 

 

B. The correct answer is False

Explanation: Stratospheric ozone is “good” because it protects living things from ultraviolet radiation from the sun.

 

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Air Quality

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Last updated on May 5, 2025