AIR QUALITY
People need to breathe. If they don’t breathe, they (1)______ die. But how clean is the air people breathe? If they breathe (2)______ air, they will have breathing problems and become (3)_______. Plants and animals need clean air too. A lot of the things in our lives create harmful gases and (4)______ the air dirty, like cars, motorbikes and factories. Dirty air is called “(5)_______ air”. Air pollution can also make our Earth warmer. The problem of air pollution started with the burning of coal in homes and factories.
