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. Stratospheric ozone is made up of three oxygen atoms, and has no color, no taste, and not much odor.