Good ozone, bad ozone
Ozone high up protects, ozone near the ground harms.
The same gas in two places
Ozone high in the stratosphere blocks the Sun's UV rays.
Is ozone near the ground, in city air, also good for us?
What this lesson covers
The idea
Vehicular emissions react with sunlight to form ground-level smog and ozone, which is harmful, unlike ozone in the stratosphere, which blocks UV radiation and protects life.
The same gas in two places
Ozone high in the stratosphere blocks the Sun's UV rays.
Is ozone near the ground, in city air, also good for us?
- No, it is harmful
- Yes, just as good
- It has no effect
Two places, two effects
Put each fact where it belongs.
Same gas, different place
Ozone is good high above us, where it shields us from UV. Close to the ground it is a pollutant. Together with smog it makes city air unhealthy.
Vehicular emissions react with sunlight to form ground-level smog and ozone, which is harmful, unlike ozone in the stratosphere, which blocks UV radiation and protects life.
Notes
Vehicular emissions react with sunlight to form harmful ground-level smog and ozone. Ozone in the stratosphere blocks UV and protects life.
Check yourself
What reacts with sunlight to form ground-level smog and ozone?
Is ozone at ground level good or bad for health?
What does ozone in the stratosphere do?
What do these pollutants do to city air?
- Vehicular emissions — correct. Yes!
- Ozone in the stratosphere. Ozone in the stratosphere blocks UV radiation. Vehicular emissions react with sunlight to form ground-level smog.
- Water vapour from oceans. The chapter names vehicular emissions as reacting with sunlight to form ground-level smog.
- Protective, like the ozone layer. Ozone in the stratosphere is protective. Ozone at ground level is harmful for health.
- Harmful for health — correct. Yes!
- It makes the air cleaner. Ground-level smog and ozone make city air unhealthy.
- Makes smog in cities. Smog forms near the ground from vehicular emissions reacting with sunlight.
- Harms health at ground level. That is ground-level ozone. Ozone in the stratosphere is protective.
- Blocks UV radiation and protects life — correct. Yes!
- Make it unhealthy — correct. Yes!
- Make it cleaner. The pollutants make city air unhealthy.
- Make it colder. The chapter says these pollutants make city air unhealthy.