Chapter 14: Lesson 14.1 Common Hazards in the Environment

The Environment

When you think about health, you probably think about the actions you take to stay healthy. How and when you get , the food you eat, and how much sleep you get all have important effects on your health. Your health is also by the environment in which you live, however.

all live on planet Earth and depend on the planet’s resources, such as water, animals, trees, air, other plants, and . How people use these resources affects the environment, which then influences people’s health (Figure 14.1).

Unfortunately, people do not always treat their environment with the care it deserves. Human activities can harm the and negatively affect people’s health. This harm can lead to hazards like air pollution, water pollution, and chemical pollution.

The field of environmental health examines how factors in the natural environment, such as air, water, and soil, impact your health. Environmental factors also include spaces made by people, such as , , , and .

Air Pollution

Humans by breathing in air. Air contains , which people need to survive. Air also contains other gases, including , , and . Sometimes, air contains other substances, known as pollutants, which contaminate the environment and can harm people.

Outdoor Air Pollution

The is influenced by natural forces in the environment. For example, a releases smoke and carbon monoxide into the air. A releases carbon dioxide, sulfur dioxide, and other chemicals, as well as ash (Figure 14.2). Wind currents can carry these for thousands of miles.

The air outside is also affected by . You might have seen pictures of smog hanging over a big city. is a fog that has mixed with smoke and chemical fumes (Figure 14.3). Car is a major cause of smog in cities. The burning of , , and to power cars and produce electricity also pollutes the air. Even tractors on farms create dust clouds when plowing the fields.

When are released into the air, they mix with water, oxygen, and other chemicals to form acids. These then fall to the ground as rain, snow, hail, fog, or even dust. Any form of precipitation that includes particles containing acid is known as acid rain.

Another source of air pollution is , which is made up of tiny particles and drops of liquid. These tiny particles and liquids that float in the air can include chemicals, metals, and dust. Some particulate matter is natural. One example is pollen from and carried on the wind. Particulate matter can also be created by human actions, such as cooking on a grill or burning fuel in a power plant.

Indoor Air Pollution

can also contain pollutants. can be caused by many different factors (Figure 14.4). Some of these pollutants can be seen or smelled. For example, you can see smoke from cigarettes and smell some cleaning products.

Mold can be seen growing in wet places and can cause and infections. The natural mineral can release cancer-causing fibers. Scented products such as and release chemicals that can irritate the eyes, nose, and throat.

Other types of pollutants have and are so small that you cannot see them. For example, very tiny bugs, called , are one of the most common causes of indoor air pollution. Dust mites live in , upholstered furniture, rugs, or . Their bodies and waste matter can trigger allergic reactions and asthma in humans.

Effects of Air Pollution

Breathing in pollutants can cause . In some cases, it can cause very serious conditions, such as cancer and heart disease. Air pollution can also make current health conditions worse. For example, smog can make it very difficult for people with to breathe.

Particulate matter can get into people’s . Larger particles can irritate the eyes, nose, and throat. You have probably experienced this type of if you have sat close to a charcoal grill or beside a campfire (Figure 14.5).

is a gas made up of oxygen that naturally exists high above Earth’s atmosphere. It helps protect people from the damaging (UV) rays produced by the sun. Some kinds of air pollution caused by humans can damage this ozone layer, which increases the amount of UV rays reaching Earth. UV rays can cause . Too much UV radiation may also damage plants, including crops grown for food. Ozone poses other dangers, too. Ozone close to the ground can cause respiratory conditions and . Ground-level ozone is usually caused by chemical reactions between different pollutants in the air.

Air pollution also has an effect on Earth’s climate. Earth’s is made up of different gases, including nitrogen, oxygen, and carbon dioxide. These gases trap the energy produced by the sun, which warms Earth. As a result, Earth maintains a balanced and stable temperature over time.

When these gases build up in the , however, they trap more heat near the surface of Earth. The effects of this buildup can change climates around the world. Many have concluded that the buildup of gases released by burning fuels to produce energy has resulted in climate change. can lead to shifts in weather patterns. These changes can lead to more major disasters, such as , , droughts, and floods. Scientists also warn that rising temperatures will melt ice on Earth’s surface. This melting ice can raise sea levels and threaten in coastal areas (Figure 14.6).

Water Pollution

Humans need water to drink in order to . More than of Earth’s surface is covered by , but most of this water is in the ocean. People cannot use salty ocean water for drinking. They need freshwater for drinking.

Only about three percent of the water on Earth is . Most of this freshwater is frozen in the polar and glaciers. This leaves only about one percent of the water on Earth available to use as drinking water. Usable sources of freshwater are found in lakes, rivers, and reservoirs. There is also freshwater inside Earth. These combined sources provide the freshwater needed for farms, homes, , factories, and . Unfortunately, if this water becomes polluted, it is no longer safe for humans to drink.

A number of factors can the water. Water can be polluted by human-made products, such as chemicals and pollutants, but also by natural .

Human Causes of Water Pollution

The products that people use in their daily lives can end up in the . When rain or melted snow is not absorbed on Earth’s surface, it becomes runoff, travels over the ground, and picks up loose soil and (Figure 14.7). These pollutants can include the following:

• pesticides and from lawns and fields

• oil, grease, and chemicals from cars, , and other vehicles

• and chemicals from factories and construction sites

• animal from agriculture

Runoff travels to bodies of water, such as , , , and . People can then use it for washing food, bathing, or drinking. Exposure to chemicals and pollutants through these activities can make people sick (Figure 14.8).

Natural Causes of Water Pollution

Major , such as hurricanes, typhoons, and earthquakes, can cause water pollution. During hurricanes and floods, pollutants that are usually stored in landfills or other disposal areas are swept into waterways. Examples are , fertilizers, chemicals, and oil. can trigger tsunamis, or tidal waves, which flood an area with saltwater. This water can destroy farmland and crops.

Tiny , such as bacteria, viruses, and parasites, can live in the water supply. Even though you cannot see these , drinking water that contains them can make people . In the case of a disaster, the water supply of a whole town or area can be . In some cases, people can even die from drinking this water.

Water Treatment

People use water every day—to drink, to take a shower, and to wash clothes and dishes. This water comes from of water, such as streams, ponds, and rivers.

in the United States is treated in a water treatment plant. This process takes between 8 and 16 hours. The process involves removing from the water and cleaning the water before people use it and before it returns to the environment. All water people use goes through a before it is used in , , or (Figure 14.9). This water is also tested to make sure it is safe to use. This process is designed to protect people from drinking polluted water that can cause and other health conditions.

Chemicals

are substances that have specific properties or characteristics. Some chemicals are found in nature. For example, (ascorbic acid) is a chemical naturally found in some fruits. Other chemicals are made by people. For example, (acetylsalicylic acid) is a chemical made by people from substances found in . People use chemicals every day, in many different ways. You are exposed to chemicals through items you , but also through the air you breathe and even through the objects you touch.

Types of Chemicals

Many chemicals are safe for people to use, at least in amounts. Minerals, such as iron, are naturally occurring chemicals that your body needs to stay healthy. Some kinds of chemicals, however, are . This means people can get sick from coming into contact with these chemicals by touching them, something that contains them, or inhaling them (Figure 14.10). It is important to know what these chemicals are and where they are found so you can be safe. These chemicals include the following:

• Mercury.

is found in and household products such as , paint, glass thermometers, and compact fluorescent light bulbs. Eating fish with high levels of mercury and disposing of mercury-containing products inappropriately can have harmful effects. Natural events, such as forest fires, and the burning of fossil fuels can also release mercury into the air.

• Lead.

was used in household products such as , gasoline, and pesticides before 1978. It was used in water pipes before 1986. Exposure to lead-based products and water containing lead can harm people’s health. Exposure to lead as a fetus harms brain development and causes long-term problems with learning and growth. Trained people can test homes for lead and recommend steps to take to remove it.

• Bisphenol A (BPA).

is a chemical found in many . Scientific research shows that BPA may pose health risks (Figure 14.11). Many plastic products, such as water bottles and food containers, are now labeled BPA-free if this chemical is not used in the product.

• Arsenic.

naturally occurs in rocks, soil, water, and air. It can lead to water pollution when rain or melted snow runs over the ground. can also be released from mining and is used in some products that protect wood against termites. Exposure to arsenic can cause serious health conditions.

• Pesticides

are chemicals that control, or , weeds, bugs, and rodents. Pesticides can cause harm if they are ingested with food. can also carry pesticides from lawns, gardens, and farms into nearby bodies of water.

Whether a is harmful to your health depends on a number of factors. These factors include how you are exposed to the chemical, how long you are exposed to it, and the amount of the chemical to which you are exposed. Certain groups of people, such as babies, have an increased risk of harm due to (Figure 14.12). Exposure to toxic chemicals can lead to nausea and vomiting, skin or eye conditions, and cancer. Exposure to some chemicals, such as pesticides (which are poisons), can cause death.

If you are worried that you have been exposed to a dangerous chemical, talk with your doctor, , or another trusted adult. You can also call the Poison Control Center at . This resource is very helpful if you think you or someone you know has been in contact with a harmful substance.

Safe Chemical Use

To prevent harm from , use household chemicals, such as paint and cleaning supplies, properly. Make sure to read warning labels carefully before using any kind of chemical. Other strategies for protecting yourself—and the —from chemicals include the following:

• labels and learn the symbols placed on the packages of chemicals (Figure 14.13). These symbols explain how the chemicals may impact a person’s health and whether they can hurt the environment.

• Be very careful about mixing different chemicals together. For example, mixing bleach and products containing produces a highly toxic gas.

• Protect your from chemical exposure. and other protective equipment, depending on the type of chemical product you are using. Make sure to wash your hands carefully with soap and water after using chemical products.

• When using chemical products, or leave windows open.

• of chemical products properly. Keep them away from items used in cooking and eating. Do not move chemicals into new containers.

Noise Pollution

You are surrounded by sounds. People listen to , , and . Cars, trucks, trains, and planes make sounds. Construction equipment generates sound, too. Some sounds are , such as the sound of waves hitting the shore or birds calling to one another.

When do these sounds become a concern? When do sounds become noise? Noise is sound that a person does not want to hear or is bothered by. Noise can be more than simply bothersome. It can affect a person’s health. During the day, noise causes , raises blood pressure, and interferes with concentration. Noise at interferes with sleep, causing daytime tiredness, , and anxiety and depression.

High levels of noise over a period of time can lead to a . That is one reason that doctors warn about listening to music over at levels. Some studies have found that one in five teens suffers from some hearing loss.

Experts recommend setting the volume at no more than about of full volume when listening to a device through earphones. when operating loud equipment such as power mowers also helps.