✨ Introduction

Welcome to your first course about air! You might not have seen it, but air is all around you and essential for life. Today, we’ll learn what clean air is and why it matters.

📊 What does air contain?

Air is a mixture of gases. The most important ones are:

• Nitrogen (N2) – 78%

• Oxygen (O2) – 21%

• Carbon dioxide (CO2) – 0.04%

• Other gases (argon, water vapor, etc.)

This mix is invisible, but it keeps us alive. Oxygen, for example, is essential for our cells to work.

🌍 What does “clean air” mean?

Clean air is air that does not contain harmful substances for humans.

Pollutants can come from:

• traffic,

• smoke from fireplaces,

• cleaning products,

• dust on desks or floors.

🎨 Activity: Drawing Air Molecules

Imagine each molecule in the air is a colored ball. Draw:

• blue circles for oxygen,

• yellow for nitrogen,

• red for CO2.

Then add small gray dots – those are pollutants. Compare a clean area (forest) with a polluted one (near a road).

🎓 Final Quiz (answer on your own):

1. What is the most abundant gas in the air?

2. What gas do we breathe to stay alive?

3. What is PM2.5?

4. Why is it important to have clean air in classrooms?

🚀 What did you learn?

• Air is a mix of gases.

• We can’t see air, but it affects us.

• Pollutants can be harmful even if they have no smell or color.