We get the oxygen we need by breathing air. It’s such a natural thing that we don’t usually stop to think about what’s in the air we breathe. But besides oxygen and other elements like nitrogen, air also contains pollutants, which can be harmful. Air pollution is a problem that affects life all over the world.

Many human activities create air pollution. In turn, the pollution causes problems for our health and other life on Earth. To help improve air quality, it’s important that we learn about what causes air pollution — and what we can do to protect life on our planet.

When we talk about air pollution, we often think of smog, chemicals produced by factories or exhaust from cars. These are problems that usually affect the air outdoors. But most of us spend much of our lives inside buildings. We go to school or work indoors. We eat our meals, do our homework, play and sleep indoors. All of that time, we breathe air that is in the room.

Indoor air can become polluted, or spoiled, by adding harmful things to it, just as outside air can. For example, household cleaners, dust, paints, bug sprays, smoke from cooking or cigarettes, and fibers from some building materials all can make indoor air unhealthy to breathe. We often need to keep doors and windows closed to keep the insides of our buildings cool in the summer or warm in the winter. This can trap pollutants inside for a long time. It also can make places for insects, dust mites and molds to live.

Some pollutants of indoor air are so irritating that they can bother anyone who breathes them. Indoor pollution can come from:

• Paint
• Tobacco smoke
• Furniture and carpeting (for example, chemicals that make them difficult to burn)
• Building materials
• Scented candles (burning candles releases pollutants)
• Cleaning products
• Mold
• Pet dander (skin flakes from an animal’s hair or fur)

Other polluters can cause more problems for some people than for others. For example, some people are allergic to things in dust. When they breathe dusty air, people with allergies may start to sneeze or have runny noses and itchy eyes. Once in a while, more serious breathing problems, such as asthma, are caused by dust.

How can we keep the air inside our homes and other buildings clean and safe? A little common sense goes a long way. We can be careful about using chemical cleaners, paints, glues and pesticides, and, instead, use products that don't pollute. We can reduce the amount of dust in the air by changing the filters in our home heating and cooling systems.

We can get rid of some sources of indoor air pollution completely. For example, smoking is no longer allowed in many public buildings, such as movie theaters, hospitals and schools.

Most importantly, we can remember how important it is to have clean air to breathe inside our homes, schools and offices. Each of us can do something to help keep our indoor air clean.

Think about what would happen if you put salt in your cookie dough instead of sugar. Yuck! When you follow a recipe, you need to measure the right amount of ingredients to get the best results. It’s all about balance. In a similar way, the Earth maintains a balance of "ingredients" in the atmosphere. These ingredients are gases, such as nitrogen, oxygen, and carbon dioxide.

Some gases have the ability to trap the sun’s energy and warm the Earth. This helps balance the Earth’s temperature, keeping it stable over time. However, too few or too many of these gases in the atmosphere can mess up the balancing act. Human activities increase the amount of these gases, causing a “greenhouse effect” that makes the Earth’s temperature rise.

What are the greenhouse gases?

Carbon dioxide is the primary greenhouse gas. Other greenhouse gases include:

• Chlorofluorocarbons (CFCs)
• Methane
• Nitrous oxide
• Ozone
• Volatile organic compounds (VOCs)

What human activities increase greenhouse gases?

Activities that can increase greenhouse gases include:

• Deforestation (cutting down trees)
• Electricity production
• Farming (manure gases)
• Fossil fuel use (burning oil, coal, propane, diesel fuel, natural gas, and gasoline)
• Industrial processes
• Landfills
• Wastewater management

Volatile organic compounds (VOCs) are chemicals that evaporate from a solid or liquid form at room temperature. Some VOCs exist naturally in the environment. Others are manufactured (made by people) and put into things that we use every day.

When VOCs evaporate into the air, they become invisible, so you can’t see them. Many VOCs also have no odor (smell). That makes it easy to breathe them in without knowing it.

The word “volatile” means unstable and possibly dangerous. That word gives you a clue about what VOCs are like — and why we need to be careful with them.

What products might have VOCs in them?

Many things that we use at home, school, and work contain VOCs. These include:

• Air fresheners
• Cleaning supplies
• Fuels
• Glue
• Hair spray
• Markers
• Paint

How can people be exposed to VOCs?

When someone uses a product with VOCs, the VOCs evaporate and stay in the air. This usually happens inside a room or building, because there’s less ventilation (air flow) than outside.

In other words, VOCs can affect indoor air quality. When we say “indoor air quality,” we’re usually talking about how the air you breathe when you’re inside might affect your health. And since most of us spend a lot of time indoors, the quality of that air matters.

You can also get sick by swallowing or touching VOCs. That’s why things such as cleaning supplies have warning labels — and why it’s important to read product warnings.

How can VOCs affect my health?

VOCs can make you sick. Someone who’s been poisoned by a VOC could develop:

• Damage to the central nervous system (the system that includes the brain and spinal chord)
• Eye, nose, or throat problems
• Headaches
• Liver or kidney damage

Some VOCs can also cause cancer if people are exposed to them for a long period of time.

Some content courtesy of the National Library of Medicine.

A single atom can make a big difference in the way a molecule works — so can its location. The everyday air we breathe has two atoms of oxygen (O2) in it. Ozone is a gas made up of three atoms of oxygen (O3). And while we need oxygen to survive, ozone can either help us or hurt us — depending on where it is.

What’s the difference between helpful and harmful ozone?

Ozone can be helpful or harmful to your health and the environment, depending on its location in the atmosphere. Helpful ozone exists naturally high above the Earth’s surface and protects us from the sun’s ultraviolet rays (radiation). Human-made air pollutants damage the helpful ozone.

Harmful ozone is close to the ground. It comes from human activities that release chemicals into the air, which react with sunlight to create ground-level ozone.

How can ozone affect my health?

When human-made air pollutants destroy helpful ozone, people may receive too much ultraviolet radiation. This may cause:

• Cataracts (clouding of eye lens, which leads to poor vision)
• Problem with immune system (the system that fights diseases)
• Skin cancer

Too much ultraviolet radiation may also damage crops (plants we grow for food) and other plants.

Contact with harmful ozone can cause:

• Coughing
• Irritated throat
• Worsening in respiratory (breathing) disorders, such as asthma and bronchitis

Regular contact with ozone can also cause permanent damage to the lungs, especially in children, because their lungs are still developing.

Electricity is an essential part of our lives.

Electricity powers all sorts of things around us, from computers to refrigerators Use of electric power is something we take for granted.

What are electric and magnetic fields?

Electric and magnetic fields (EMF) are invisible lines of force that surround any electrical device. Power lines, electrical wiring, and electrical equipment all produce EMF.

Some people wonder whether EMF might have some bad effects our health.

We are exposed to EMF almost everywhere we go, at home, at school, in stores, and even outside when we are near all types of electrical equipment, wiring, and power lines.

EMF decreases rapidly as you get farther away from the source.

Alternating current (AC) or direct current (DC)?

In the United States, if something is plugged into a household wall socket, it is using AC. AC reverses direction in the electrical wiring—or alternates—60 times per second, or at 60 hertz (Hz). If something uses batteries, the electric current flows in one direction only, and it is using DC.

What happens when I am exposed to EMF?

In most practical situations, DC electric power does not induce electric currents in humans. AC electric power produces electric and magnetic fields that create weak electric currents in humans.

Being exposed to some kinds of EMF may have some bad effects on humans, but scientists do not know for sure. Because of this, NIEHS recommends that people learn practical ways of reducing exposures to EMFs.

Have you ever noticed smog over a big city?

Then you’ve actually seen outdoor air pollution.

Some outdoor air pollution is invisible to us, of course, but it can still affect our lives.

Where does outdoor air pollution come from?

Many factors play a role in outdoor air quality. Natural things like volcanic eruptions, wildfires, wind currents, and trees can affect it. Some human activities add pollutants into the air. Think of factories and power plants pumping out smoke and chemicals, and tractors on farms blowing up dust clouds.

How can outdoor air pollution affect my health?

When we breathe in pollutants, they can create health problems — or make existing health problems worse. For example, they may trigger symptoms of asthma, or cause other kinds of breathing problems. Some polluters can cause more problems for some people than for others. Air pollution can also cause heart disease and cancer.

Some content courtesy of the National Library of Medicine.

Asthma and allergy attacks have increased in the United States despite the fact that our outdoor air quality has improved. Some researchers think these problems have increased because kids are spending too much time indoors.

When outdoors, we are exposed to pollens and dust, and other irritants. But when indoors, we are also exposed to "allergens." Allergens are proteins that originate from cockroaches, mold, pets, and dust mites (tiny bug-like creatures that live in dust). Allergens cause allergies.....and most people know that allergies can make you sniffle, sneeze, have runny and itchy eyes, and other cold-like symptoms. But allergens can also trigger asthma attacks, which are more serious. Asthma symptoms include wheezing (a high-pitched whistling sound heard when exhaling); coughing spells unrelated to a cold; shortness of breath, especially during exercise; and tightness in the chest. Allergic asthma affects about 3 million children (8 to 12 percent of all children) and 7 million adults in the United States each year!

roaches....

and dust mites...

What Can You Do?

Reduce the allergens from YOUR environment! Most children with asthma are allergic to something, and so staying away from the "allergen" should help control the asthma. If you have asthma or allergies, stay away from animals, remove the teddy bears, rugs, curtains and lamp shades in rooms that you stay in a lot, like the bedroom. Plastic mattress and pillow covers, exterminators for pesky bugs, and the elimination of dust-traps like curtains and rugs in your bedroom may help you breathe easier. Or if it's trees and pollen that get to you, air conditioning and air filters should help. Read a fun "make-believe" story about "Dustmitezilla" - a dust mite of giant proportions!

And Research Helps Too!

Children whose parents or brothers and sisters have asthma are more likely to develop it themselves. But even though our "genes" do play some part in whether or not we'll have asthma, researchers hope to make the most progress in fighting the disease by looking at the environmental aspect of asthma. The hope is that if kids encounter fewer allergens early in life, they'll be less likely to develop allergic responses.

Asthma triggers are things that set off or worsen asthma symptoms. If you know that your asthma symptoms occur when you are exposed to specific triggers, it may be worthwhile to reduce your exposure to those triggers, using multiple different methods to reduce the exposure.

Allergens are a common trigger for asthma.

• If you are sensitive to dust, consider using a mattress and pillowcases that keep out dust mites along with high efficiency particulate air (HEPA) filtration vacuum cleaners.
• If you are sensitive to mice or cockroaches, consider using multiple ways of removing them or preventing them from entering the home in the first place.

Other asthma triggers include:

• Emotional stress. Emotional stress, such as intense anger, crying, or laughing, can cause hyperventilation and airway narrowing, triggering an asthma attack.
• Infections, such as influenza (flu). Get the flu vaccine each year to help prevent the flu, which can raise the risk of an asthma attack.
• Medicines. Some people who have severe asthma may be sensitive to medicines, such as aspirin, and may experience serious respiratory problems. Tell your doctor about all medicines you or your child currently takes.
• Poor air quality or very cold air. Pollution or certain kinds of weather, such as thunderstorms, can affect air quality. Pollution can include indoor pollution caused by gases from inefficient cooking or heating devices that are not vented. Outdoor air pollution may be hard to avoid, but you can keep windows closed and avoid strenuous outdoor activity when air quality is low.
• Tobacco smoke, including secondhand smoke.
• Certain foods or food additives (chemicals). This is less common.

Secondhand smoke is the smoke from a cigarette, cigar or pipe, and the smoke exhaled by a smoker. Secondhand smoke contains more than 4,000 substances, including several compounds that cause cancer.

Secondhand smoke can trigger asthma episodes and increase the severity of attacks. Secondhand smoke is also a risk factor for new cases of asthma in preschool-aged children. Children's developing bodies make them more susceptible to the effects of secondhand smoke and, due to their small size, they breathe more rapidly than adults, thereby taking in more secondhand smoke. Children receiving high doses of secondhand smoke, such as those with smoking parents, run the greatest relative risk of experiencing damaging health effects.

Actions You Can Take

• Don't let anyone smoke near your child.
• If you smoke — until you can quit, don't smoke in your home or car.

Dust mites are tiny bugs that are too small to see. Every home has dust mites. They feed on human skin flakes and are found in mattresses, pillows, carpets, upholstered furniture, bedcovers, clothes, stuffed toys and fabric and fabric-covered items.

Body parts and droppings from dust mites can trigger asthma in individuals with allergies to dust mites. Exposure to dust mites can cause asthma in children who have not previously exhibited asthma symptoms.

Actions you can take

• Common house dust may also contain asthma triggers. These simple steps can help: Wash bedding in hot water once a week. Dry completely.
• Use dust proof covers on pillows and mattresses.
• Vacuum carpets and furniture every week.
• Choose stuffed toys that you can wash. Wash stuffed toys in hot water. Dry completely before your child plays with the toy.
• Dust often with a damp cloth.
• Use a vacuum with a HEPA filter on carpet and fabric-covered furniture to reduce dust build-up. People with asthma or allergies should leave the area being vacuumed.

Molds create tiny spores to reproduce, just as plants produce seeds. Mold spores float through the indoor and outdoor air continually. When mold spores land on damp places indoors, they may begin growing. Molds are microscopic fungi that live on plant and animal matter. Molds can be found almost anywhere when moisture is present.

For people sensitive to molds, inhaling mold spores can trigger an asthma attack.

Actions You Can Take

• If mold is a problem in your home, you need to clean up the mold and eliminate sources of moisture.
• If you see mold on hard surfaces, clean it up with soap and water. Let the area dry completely.
• Use exhaust fans or open a window in the bathroom and kitchen when showering, cooking or washing dishes.
• Fix water leaks as soon as possible to keep mold from growing.
• Dry damp or wet things completely within one to two days to keep mold from growing.
• Maintain low indoor humidity, ideally between 30-50% relative humidity. Humidity levels can be measured by hygrometers, which are available at local hardware stores.

Droppings or body parts of cockroaches and other pests can trigger asthma. Certain proteins are found in cockroach feces and saliva and can cause allergic reactions or trigger asthma symptoms in some individuals.

Cockroaches are commonly found in crowded cities and the southern regions of the United States. Cockroach allergens likely play a significant role in asthma in many urban areas.

Actions You Can Take

• Insecticides and pesticides are not only toxic to pests — they can harm people too. Try to use pest management methods that pose less of a risk.
• Keep counters, sinks, tables and floors clean and free of clutter.
• Clean dishes, crumbs and spills right away.
• Store food in airtight containers.
• Seal cracks or openings around or inside cabinets.

Proteins in your pet's skin flakes, urine, feces, saliva and hair can trigger asthma. Dogs, cats, rodents (including hamsters and guinea pigs) and other warm-blooded mammals can trigger asthma in individuals with an allergy to animal dander.

The most effective method to control animal allergens in the home is to not allow animals in the home. If you remove an animal from the home, it is important to thoroughly clean the floors, walls, carpets and upholstered furniture.

Some individuals may find isolation measures to be sufficiently effective. Isolation measures that have been suggested include keeping pets out of the sleeping areas, keeping pets away from upholstered furniture, carpets and stuffed toys, keeping the pet outdoors as much as possible and isolating sensitive individuals from the pet as much as possible.

Actions You Can Take

• Find another home for your cat or dog.
• Keep pets outside if possible.
• If you have to have a pet inside, keep it out of the bedroom of the person with asthma.
• Keep pets off of your furniture.
• Vacuum carpets and furniture when the person with asthma is not around.

Nitrogen dioxide (NO2) is an odorless gas that can irritate your eyes, nose and throat and cause shortness of breath. NO2 can come from appliances inside your home that burn fuels such as gas, kerosene and wood. NO2 forms quickly from emissions from cars, trucks and buses, power plants and off-road equipment. Smoke from your stove or fireplace can trigger asthma.

In people with asthma, exposure to low levels of NO2 may cause increased bronchial reactivity and make young children more susceptible to respiratory infections. Long-term exposure to high levels of NO2 can lead to chronic bronchitis. Studies show a connection between breathing elevated short-term NO2concentrations, and increased visits to emergency departments and hospital admissions for respiratory issues, especially asthma.

Actions You Can Take

If possible, use fuel-burning appliances that are vented to the outside. Always follow the manufacturer's instructions on how to use these appliances.

• Gas cooking stoves: If you have an exhaust fan in the kitchen, use it when you cook. Never use the stove to keep you warm or heat your house.
• Unvented kerosene or gas space heaters: Use the proper fuel and keep the heater adjusted the right way. Open a window slightly or use an exhaust fan when you are using the heater.

Outdoor air pollution is caused by small particles and ground level ozone that comes from car exhaust, smoke, road dust and factory emissions. Outdoor air quality is also affected by pollen from plants, crops and weeds. Particle pollution can be high any time of year and are higher near busy roads and where people burn wood.

When inhaled, outdoor pollutants and pollen can aggravate the lungs, and can lead to:

• Chest pain
• Coughing
• Digestive problems
• Dizziness
• Fever
• Lethargy
• Sneezing
• Shortness of breath
• Throat irritation
• Watery eyes

Outdoor air pollution and pollen may also worsen chronic respiratory diseases, such as asthma.

Actions You Can Take

Get more information about Ozone Maps, Air Quality Forecasts, Ozone Action Days and more.

• Monitor the Air Quality Index on your local weather report.
• Know when and where air pollution may be bad.
• Regular exercise is healthy. Check your local air quality to know when to play and when to take it a little easier.
• Schedule outdoor activities at times when the air quality is better. In the summer, this may be in the morning.
• Stay inside with the windows closed on high pollen days and when pollutants are high.
• Use your air conditioner to help filter the air coming into the home. Central air systems are the best.
• Remove indoor plants if they irritate or produce symptoms for you or your family.
• Pay attention to asthma warning signs. If you start to see signs, limit outdoor activity. Be sure to talk about this with your child's doctor.

Chemical irritants are found in some products in your house and may trigger asthma. Your asthma or your child's asthma may be worse around products such as cleaners, paints, adhesives, pesticides, cosmetics or air fresheners. Chemical irritants are also present in schools and can be found in commonly used cleaning supplies and educational kits.

Chemical irritants may exacerbate asthma. At sufficient concentrations in the air, many products can trigger a reaction.

Actions You Can Take

If you find that your asthma or your child's asthma gets worse when you use a certain product, consider trying different products. If you must use a product, then you should:

• Make sure your child is not around.
• Open windows or doors, or use an exhaust fan.
• Always follow the instructions on the product label.

Smoke from wood-burning stoves and fireplaces contain a mixture of harmful gases and small particles. Breathing these small particles can cause asthma attacks and severe bronchitis, aggravate heart and lung disease and may increase the likelihood of respiratory illnesses. If you're using a wood stove or fireplace and smell smoke in your home, it probably isn't working as it should.

Actions You Can Take

• To help reduce smoke, make sure to burn dry wood that has been split, stacked, covered and stored for at least 6 months.
• Have your stove and chimney inspected every year by a certified professional to make sure there are no gaps, cracks, unwanted drafts or to remove dangerous creosote
  build-up.
• If possible, replace your old wood stove with a new, cleaner heating appliance. Newer wood stoves are at least 50% more efficient and pollute 70% less than older models.
  This can help make your home healthier and safer and help cut fuel costs.

Have you?

Then you know that even if the equipment looks scary, it doesn't hurt you! And you may also know how important such equipment can be for helping scientists and doctors determine what is causing various health problems!

Scientists use special equipment like microscopes, MRIs (Magnetic Resonance Imaging), CAT scans (Computerized Axial Tomography), and X-rays to help them see things they can't see with the "naked eye." MRI's, CAT scans, and X-rays can look inside our bodies to help determine what may be wrong when we are sick.

Here's what an MRI looks like!

The technology developed from the early discovery of uranium, the process of fission, and nuclear weapons, has also provided us with many lifesaving diagnostic tools in the field of Nuclear Medicine! These medical tools, and radioactive materials are essential elements in medical research, cures for cancer, and the safety of industrial processes.

There are many beneficial uses of radiation and radioactivity—for example, radiation is frequently used for cancer treatments, where tumors are exposed to high levels of radiation in a controlled setting. Using radiation alone or in addition to chemotherapy, persons with leukemia, lung cancer, cervical cancer, bone cancer, Hodgkin's Disease, and thyroid cancers have been cured.

In addition radioactive materials such as tritium, carbon-14, sulfur-35, phosphorus-32 and others produced in nuclear reactors are used to label cells, proteins, and various chemicals. These labeled chemicals have allowed us to unlock the mysteries of the human brain, diagnose disease, and study the human body (both it's genetics and physiology)!

However, when not handled properly or when proper safety procedures are not followed, radioactive materials can cause harm to our bodies and possibly could cause cancer.

Radiation Exposures and Safety Precautions:

Early uranium miners were exposed to elevated levels of radon gas and thus the decay products of radon. These miners showed an increased risk of lung cancer. So with that knowledge in hand, modern mines have increased ventilation rates to prevent this type of exposure.

Radium present in the mill tailings of the uranium extraction process and used to paint glow-in-the-dark watch and clock dials, was not disposed of properly in some areas in the past. This improper handling of radium caused many cases of cancer in watch-dial painters who licked the brushes and ingested the radium in the paint. Improper disposal of the waste from these industries also contaminated homes, parks, and buildings across the United States. With those concerns in mind, steps have been taken to inform the public of such risks and reduce the possibility of such exposures.

You can't see radon. And you can't smell it or taste it. But it may be a problem in your home. Radon comes from the natural breakdown of uranium in soil, rock, and water. Radon is the second leading cause of lung cancer in the United States.

There are low levels of radon outdoors. Indoors, there can be high levels. Radon can enter homes and buildings through cracks in floors, walls, or foundations. Radon can also be in your water, especially well water. Testing is the only way to know if your home has elevated radon levels. It is inexpensive and easy. You can buy a test kit at most hardware stores or hire someone to do a test. Radon reduction systems can bring the amount of radon down to a safe level. The cost depends on the size and design of your home.

Water is essential for survival on Earth. It makes up almost two-thirds of our body weight and covers a little over two-thirds of the Earth’s surface. Since almost all of the water is in salty oceans, we can’t use it for drinking. In fact, only about 3% of the Earth’s water is fresh, and most of that fresh water is frozen. That means only about 1% of the water on Earth is available for people to use.

The chemical formula “H₂0” shows the basic units of a water molecule: two hydrogen atoms and one oxygen atom. We describe water as a colorless liquid that you can’t smell or taste. Water also comes in the form of ice in the polar ice caps and water vapor (gas) that rises into the air from the surface of our planet.

Explore the links below to learn fun facts about water, how important it is to life on Earth, and what you can do to protect this natural resource.

Chemicals and Pollutants

It might surprise you to learn that chemicals from products we use every day can eventually end up in our water. Just look around your home. Do you see any batteries, paint, or medicines? If you don’t get rid of these products correctly, they can cause chemicals to end up in the water supply. In fact, your water can be affected by chemicals and pollutants close by and far away from your home.

How does this happen? Runoff is water from rain or melted snow that isn’t absorbed by the ground. Instead, it runs over the ground and loose soil, picking up pollution and carrying it into ponds, lakes, streams, rivers, and coastal areas. Water can be polluted by urban, industrial, or agricultural runoff. Examples of water pollutants from runoff include:

• Heavy metals and chemicals from construction sites and factories
• Oil, grease, and chemicals from our cars and trucks
• Pesticides and fertilizers from our lawns and gardens

Our drinking water can be affected by chemicals and pollution from runoff. Swimming or playing in polluted water can also make us sick.

Water is Remarkable!

Water is one of the most amazing substances on our planet. Did you know that every single living thing needs water? It is in each of the cells in our bodies and in the bodies of all plants, animals and other creatures. Water is special because it can mix with many different liquids and solids. Its ability to stay warm for a long time makes it special too. This helps keep the temperature inside our bodies around 98 degree Fahrenheit. It also helps keep the temperature in oceans, lakes and rivers from changing very quickly.

Water can be polluted easily because so many different substances will dissolve in it. Can you think of any things that seem to disappear when you mix them with water?

Each One of Us Can Do Something.

Sometimes, without knowing, we do things that harm our water supplies. When we use too much fertilizer or pesticide on lawns, gardens or fields, some of it can end up being washing into rivers and lakes. Once there, it can hurt fish and other animals. It also can make water unsafe for us to drink. Harmful chemicals can soak deep into the ground and pollute water that is found there. Even things like old paint or motor oil can be harmful if you dump them down the drain or pour them onto the ground. In the end, these things find their way back into our water.

Why is Clean Water Important?

Water is used in many ways. We need clean drinking water to stay health. Water is also important for many other things that we need. Farms need water to produce crops and livestock. Factories need water to make many products. Water is used in power plants that make electricity. Since we all use water in so many ways, we should remember to take care of our water sources.

Water Cycle

The water we use every day is very old. Just like the Earth itself, it’s been around for billions of years. The Earth has a limited amount of water that always gets recycled. It is in a closed system. Since we do not lose or gain water from other sources, it’s important to protect the water we have.

The water cycle is a natural process that happens when water rotates through different forms (solid, liquid, or vapor). The process improves the quality of water. However, people do things that create water pollution.

River and Stream Pollution

Dirt

Dirt is a big cause of pollution in our rivers and streams. Rain washes dirt into streams and rivers. Dirt can smother fish and other animals that live in the water. If plants can't get enough sunlight because the water is murky, they die.

Most of the dirt washing into lakes and streams comes from exposed earth. This exposed earth includes plowed fields, construction sites, and areas that have been logged or mined. Some of the dirt polluting streams comes from the stream banks.

The solution is to stop the dirt from getting into the stream in the first place by disturbing the land as little as possible. Farmers and construction workers are using new methods to reduce the amount of earth they disturb.

Bacteria

Bacteria are also a big water quality problem. Not all bacteria are harmful, but germs and viruses that can make you sick might be in the water. Bacteria can come from combined sewers after rainstorms and runoff of animal waste from farms, pets, and wildlife.

Sewage systems can be improved to keep untreated sewage from overflowing. Farmers are developing better ways to manage livestock manure. Dog owners are picking up after their pets.

Nutrients

Nutrients are element needed for animal or plants to grow. The two most common nutrients found in water are nitrogen and phosphorus. They cause algae to grow and can turn the water green.

The major sources of nutrients are runoff of fertilizers from farms and lawns, animal waste, sewage treatment plants, and septic systems.

Farmers, homeowners, cities, and towns are all working to reduce the amount of nutrients that get into rivers and streams.

Ponds, Lakes, and the Sea

Water in streams and rivers flows into ponds, lakes, and the sea. Keeping streams and rivers clean helps keep all the water downstream clean, too.

Waterborne Diseases and Illnesses

Would you want to go swimming in a pool of bugs, worms, and chemicals? In some natural water sources, you actually would be! You just wouldn’t be able to see them. Tiny organisms like bacteria, viruses, and parasites may live in our water supplies. Chemicals and heavy metals can get into our water, too. If you drink that water, wash your food with it, or swim or bathe in it, it might make you sick.

We call these illnesses waterborne diseases because people get them from contaminated (unsafe) water. The water can also be harmful to animals. It may cause minor or serious illness, or even death. Contaminated water can lead to disease outbreaks in a local area, country, or across the world.

Water Treatment

We take baths with clean water. We drink clean water. We wash our clothes and food with clean water. Water we use every day comes from streams, ponds, rivers, and other natural sources. These water sources can become polluted. Mother Nature does her part to clean the water through the water cycle. But the water cycle can’t keep up with the pollution that people and animals create.

In the United States, we treat drinking water before it comes to our tap so that we don’t get sick from using polluted water. We also treat water after we use it and before returning it to the environment. We do this to remove pollutants so that they don’t harm our waterways and the plants and animals that live there. All used water goes through wastewater treatment, whether it was used in homes, on farms, or in industry.