lt's all around you
What in front of you and behind behind you what all around you air. You can see air. But it there You need air to breathe All animals must breathe air We need it to stay alive
The air you breathe should be clean If it’s not, it can make you sick
Look at your hands for a moment . Are they dirty or clean ? That’s easy to tell. You can see dirt if it’s on your hands. But you can’t always see the dirt in air.
You’ve seen smoke in the air sometimes. It comes from the chimneys of houses. It comes from factories. It comes from a pile burning leaves It looks gray and dirty And it is But as the wind blows the smoke spreads out The dirt is still in the air but it’s hard to see
The air gets dirty in many other ways. Cars can make the air dirty.
So can planes. Their motors give off harmful gases. These gases make the air dirty. But cars and planes can be made so that they won’t give off so much of these gases.
In some cities there are laws against making the air dirty. Factories can’t let thick, black smoke into the air.
A special group of workers test the air. They warn people when the air is very dirty. They tell factories if they’re making too much smoke they make sure people obey the law. Does your town have a law like this?