Car's exhaust pipe with exhaust

Listen carefully to the news this summer and sometime during the year you may hear on the radio or TV a weather announcement that there is an Air Quality Advisory. This is a warning that air pollution levels are high.

You can protect your lungs on days when the air isn’t good by limiting your time outdoors. You and your community can also keep pollution 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 the air clean.

In Wisconsin, two different pollutants can trigger an Air Quality Advisory.

  • 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.
  • Particle Pollution forms all year round. It can be made of little bits of dust, pollution, smoke, or even liquid drops. Particle pollution can make people cough and feel ill.

Browse on to learn more about the Air Quality Advisory, ozone and particle pollution. Then take the Hot Days of Summer Quizzler to see how you'd do on a day with an Air Quality Advisory.

Cars, factories, boats, lawn mowers, paint cans, and other household products emit pollutants. Ground-level ozone forms when those pollutants bake in the hot summer sun. Because ground-level ozone is formed by combining these pollutants, it is called a secondary pollutant.

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.

Ground-level ozone is unstable (see 'The BIG Three'). It reacts chemically with plants, rubber, and the tissues of living creatures - including you. In fact, kids and elderly people are affected the most.

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.

Graphic of the layers of the Atmosphere

You may have heard that ozone shields us from the sun's harmful UV, or ultraviolet, rays. This type of ozone is called "stratospheric" ozone. Stratospheric ozone is made up of three oxygen atoms, and has no color, no taste, and not much odor. Stratospheric ozone is the same chemical as ground level ozone. So what's the difference?

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.

Particle pollution is made up of itty bitty pieces of dust, pollen or droplets that float around in the air. Most of the time, they are so tiny you cannot see them and in fact, the littler they are, the more dangerous they can be to breathe.

Particle Pollution forms all year round in Wisconsin. Particles come from many places! Driving down a dirt road; smoke and fires; and car, lawn and boat motor exhaust all create types of particle pollution.

The particles can stay up high in the air and travel long distances. But they most often become a problem for our health when they are trapped closer to the ground. In particular, weather conditions called temperature inversions can hold particles in the air in layers near to the ground, where we breathe them in. Temperature inversions form when warmer air above traps colder air below and the wind is too calm to mix up these air layers. It can be a real problem in winter. Have you ever driven in a hilly part of Wisconsin and seen wood smoke hanging in a valley and just kind of staying there? You were probably seeing both a temperature inversion and visible particle pollution. But remember, particles can be so small you cannot see them so sometimes particle pollution is invisible… only an air quality advisory may warn you the air is unhealthy.

When we breathe in particle pollution, it can cause us to cough or cause an asthma attack for people with asthma or other health problems. Particle pollution is most dangerous for children, older people and anyone with heart or lung diseases, including asthma.

Want to know more about the Clean Air Act? See the Environmental Protection Agency (EPA) Clean Air Act explained for the public.

This year, you can check your local TV or radio weather broadcast to find out if there's an Air Quality Advisory. In some states (but not Wisconsin), highway signs announce Air Quality Advisories 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 during an advisory..

Find out what YOU can do to keep ozone levels down.