a thick and dirty fog

a region in the atmosphere surrounding Earth protecting it against harmful sun radiation that can cause skin cancer

Human can change the environment through different activities.

Chemicals and particulates that are introduced into the air by humans and do harm to living things

a substance that makes air, water, or land dirty

Polluted air helps us to stay healthy.

gasoline not mixed with lead

It refers to natural world within which people, animals, and plants live.

There are many sources of air pollution. It can be indoor or outdoor sources.

It is the addition of harmful or unpleasant substances to air, land, or water that result in making them dirty or no longer pure.

Air is what we breathe; and breathing clean air helps us stay healthy.

Which of the following is NOT the negative effect of air pollution?

Air pollution may be indoors or outdoors.

Which of the following is an example of outdoor sources?

Which of the given examples is NOT an outdoor sources?