The Air Quality Index
Learning Objectives
Students will be able to:
- Explain what the Air Quality Index (AQI) measures
- Read and interpret AQI colors and numbers
- Make decisions about outdoor activities based on AQI
- Explain why some people need to be more careful on high AQI days
The Big Question
"How do we know if the air outside is safe to breathe?"
What is the Air Quality Index?
The Air Quality Index (AQI) is like a report card for the air! Just like you get grades at school, the air gets a score too.
- The AQI measures how clean or polluted the air is
- It uses colors to make it easy to understand
- Lower numbers mean cleaner air
- Higher numbers mean more pollution
The AQI Color Scale
The AQI uses 6 colors, kind of like a stoplight with more options:
| Color | AQI Number | What It Means | What Should You Do? |
|---|---|---|---|
| GREEN | 0-50 | Good | Go outside and play! Air is great! |
| YELLOW | 51-100 | Moderate | Most people can play outside. Some sensitive people might feel it. |
| ORANGE | 101-150 | Unhealthy for Sensitive Groups | Kids with asthma should be careful. Others can still play. |
| RED | 151-200 | Unhealthy | Everyone might feel it. Limit time outside. |
| PURPLE | 201-300 | Very Unhealthy | Stay inside if you can. Everyone is affected. |
| MAROON | 301+ | Hazardous | Emergency! Everyone should stay indoors. |
Easy Way to Remember
GREEN = GO!
Air is clean. Go play!
YELLOW = SLOW
Some people be careful
RED = STOP
Stay inside if you can
Who is "Sensitive"?
Some people are more sensitive to air pollution:
- People with asthma - their lungs are already sensitive
- Young children - still growing and breathe more air for their size
- Older adults - lungs may not be as strong
- People who are sick - bodies are already working hard
- Athletes - breathe deeply and quickly when exercising
Activity: AQI Decision Making (15 minutes)
What Would You Do?
For each scenario, decide what you would do:
Scenario 1: The AQI is 35 (GREEN). Your class wants to have PE outside. What do you do?
Scenario 2: The AQI is 120 (ORANGE). Your friend who has asthma wants to play soccer at recess. What should they do?
Scenario 3: There's a wildfire nearby and the AQI is 175 (RED). Your family planned a picnic at the park. What should you do?
Scenario 4: The AQI is 250 (PURPLE). Your dog needs to go outside. How would you handle this?
Activity: Check Today's AQI (10 minutes)
Find the AQI for Your Area
Your teacher can show you how to find the AQI at AirNow.gov or on a weather app.
Questions to answer:
- What is the AQI number for your town today?
- What color is it?
- Is it a good day to play outside?
- Should anyone be extra careful today?
When Does the AQI Get Bad?
Things That Make AQI Higher
- Wildfires (smoke travels far!)
- Hot, sunny days (smog forms)
- Lots of car traffic
- No wind to blow pollution away
- Factories making pollution
Things That Make AQI Lower
- Rain washes particles out of air
- Wind blows pollution away
- Fewer cars on the road
- Cleaner factories
- More trees and plants
Science Notebook - Unit Review (10 minutes)
Complete these sentences:
- Air is made of gases including ________, ________, and ________.
- PM2.5 particles are dangerous because ________.
- When the AQI is green, it means ________.
- When the AQI is red, you should ________.
- I can check the air quality by ________.
Draw: Create your own AQI poster with all 6 colors and what each means!
Unit 1 Key Takeaways
- Air is real - it takes up space and has gases and particles in it
- Air is mostly nitrogen (78%) and oxygen (21%)
- PM2.5 particles are tiny and can get deep into our lungs
- The AQI tells us if the air is safe - GREEN is good, RED is bad
- We can check the AQI and make smart choices about going outside!
Vocabulary Review
Air Quality Index (AQI)
A number and color system that tells us how clean or polluted the air is.
Pollution
Harmful things in the air, water, or land that can hurt living things.
Sensitive Groups
People who are more affected by pollution, like those with asthma or young children.
Hazardous
Very dangerous. When air is hazardous, everyone should stay inside.
Take It Home!
Family Activity
Check the AQI with your family for the next week. Is it usually green, yellow, or something else? Talk about what might make it change. Look for patterns - is air better on certain days?