HOT SUMMER DAYS
Air Quality Watch

Ground-level ozone, also known as tropospheric ozone, is a pollutant that can make it hard for you to breathe. It forms on hot, summer days, reaching the most dangerous levels in the afternoon and early evening. You can protect your lungs on days when the air quality isn't good by limiting your time outdoors. You and your community can also keep ozone levels low by doing simple everyday things to reduce pollution. The people, plants, and animals who need clean air to breathe will appreciate your help to keep ground-level ozone under control.

Browse on to learn more about the Air Quality Watch.

The BIG three

Ozone is made up of three oxygen atoms. "Huh?" you say, "but we breathe oxygen - so what's the big deal about ground-level ozone?" The oxygen we breathe is made up of only two oxygen atoms. Because ozone has three oxygen atoms, it is unstable and can react with things, damaging rubber, plants, and EVEN your lungs. THAT'S the big deal.

There are three main ingredients needed to make ground-level ozone: NOx, VOCs, and sunlight.

NOx stands for a group of chemical compounds called nitrogen oxides. These chemicals are made up of nitrogen and oxygen. They are created mostly by cars and other engines powered by gasoline, like lawn mowers and motorboats.

VOC stands for Volatile Organic Compound. VOCs are hydrocarbons. This means they are made up of hydrogen and carbon. VOCs are created mostly by cars, but also by industries that burn fossil fuels, such as a coal-burning power plant. Other sources of VOCs include drying paint, charcoal lighter fluid, aerosol cans, motor boats, lawn mowers, and nail polish remover.

Sunlight is the third component. The rays in sunlight cause the nitrogen oxides and VOCs to mix together. When these chemicals combine, they form ozone. Air currents then scatter this ozone all over the Lake Michigan region, where we all breathe it.

How ground-level ozone affects plants and animals (including you!)

Ozone has no color, no taste, and not much odor. It may sound harmless, but it has the ability to irritate your lungs or break down your lung tissues. Do you have asthma or do you know someone who does? Ozone can cause an asthma attack, and it can make asthma attacks worse than usual. Even people who don't have asthma can have trouble breathing on days with high levels of ground-level ozone, especially people who spend a lot of time outdoors. Even though we can't see it, scientists know ground-level ozone exists. They can measure it using special instruments that detect what's in the air we breathe.

Ground-level ozone can also damage the leaves of plants and trees. Some plants affected include soybeans, clover, onions, spinach, alfalfa, and milkweed. Trees such as lilac, aspen, ash, and white pine are also injured by ground-level ozone. Ground-level ozone can cause the leaves to fall off these plants, prevent the plants from growing very big, or even cause the plants to die. Then the humans, animals, and insects - like the Monarch butterfly that depend on these plants may not have as much food or shelter. In California this has been shown to have a serious impact on the entire ecosystem. In Wisconsin the effect has been smaller, but ozone still has an effect - for example, high levels of ozone have destroyed 10 - 20 percent of some crops.

Ozone: "Good up high, bad nearby"

The difference between stratospheric ozone and ground level ozone, (tropospheric ozone) is where each is found. One is up high, one is nearby.

The atmosphere of the Earth is divided into layers. Each layer is a little different.

Stratospheric ozone is found in the stratosphere, a layer of air way up in the atmosphere. The stratosphere is between 8 and 30 miles above the ground - too far away for you to breathe any of its air! The ozone in this layer of air protects plants, animals, and us by blocking the most harmful rays of the sun.

Tropospheric ozone, (ground-level ozone) is found in the troposphere, which is the layer of air closest to the Earth's surface. The troposphere is the air from the ground to about 8 miles up into the atmosphere - it's the air we breathe. Ozone does not naturally occur at harmful levels in the troposphere. Our ground-level ozone problems are caused by human activities.

Just remember: "Good up high, bad nearby!". You might wonder: we have too much ozone in the troposphere and not enough in the stratosphere why can't we just send tropospheric ozone up into the stratosphere? Unfortunately, we can't simply 'pump' our extra ozone into the stratosphere. So, to keep it from causing problems down here in the troposphere, we have to stop it from forming in the first place.

Want to know more about the Clean Air Act? The Environmental Protection Agency (EPA) has the Clean Air Act explained for the public on its website. (Leaving EEK!)

This summer, you can check your local TV or radio weather broadcast to find out if it's an Air Quality Watch or Advisory day. In some states (but not Wisconsin), highway signs announce Air Quality Watch/Advisory to drivers. You can also check on the web at the Wisconsin Dept. of Natural Resources and the EPA. And don't forget, on Air Quality Advisory days, it's not a good idea to breathe the air outside. So try to limit your outdoor activities until later in the evening (about 6 p.m.).

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Test your knowledge, take the Hot Summer Days Quizzler.

If you are interested in learning more about ozone, you can purchase Where's the Air?, a multimedia cd-rom. Please ask your parents for permission to send EEK! your address.