Reduction of Air Pollutants
Introduced| English |
|---|
| catalytic converter/ˌkætəˈlɪtɪk kənˈvɜːtə/ |
| scrubber/ˈskrʌbə/ |
| sulfur dioxide/ˈsʌlfɜː daɪˈɒksaɪd/ |
| particulates/pəˈtɪkjʊleɪts/ |
| laws/lɔːz/ |
Cleaning up the air
- We can cut air pollution in two big ways.
- Clean the exhaust before it leaves the pipe or stack.
- Or make less pollution in the first place.
- Both are needed to keep the air breathable.
Cleaning car exhaust
- A catalytic converter 催化转化器 sits in a car's exhaust.
- It turns harmful gases into less harmful ones.
- Carbon monoxide and nitrogen oxides are cut sharply.
- Nearly every modern car has one by law.
A catalytic converter on a car…
A catalytic converter turns harmful exhaust gases into less harmful ones before they leave the tailpipe.
Cleaning smokestacks
- A scrubber 洗涤器 strips sulfur dioxide 二氧化硫 from exhaust.
- Electrostatic filters trap particulates 颗粒物 before they escape.
- These devices sit at the top of power-plant stacks.
- They stop much of the pollution reaching the air.
Reduces or worsens air pollution?
Sort each action by whether it cuts air pollution or adds to it.
A scrubber on a smokestack removes…
A scrubber sprays or reacts the exhaust to strip out pollutants like sulfur dioxide before release.
Governments cut pollution by passing ____ that set legal limits on emissions.
Clean-air laws set legal limits, forcing factories and cars to cut their emissions.
Rules and prevention
- Governments pass laws 法律 that limit emissions.
- Factories and cars must meet legal pollution limits.
- Best of all: burn less fuel in the first place.
- Using less energy and switching to renewables cuts pollution at the source.
Using less energy and switching to renewables cuts pollution at its source.
Burning less fuel is the surest cut — no emissions to clean if they were never made.
Select all ways to reduce air pollution.
Converters, scrubbers, and renewables all cut pollution. Removing limits would make it worse.
Two strategies, ranked. End-of-pipe controls (converters, scrubbers, filters) clean the exhaust after it's made — helpful, but you still burn the fuel. Prevention (efficiency, renewables, less driving) stops the pollution being made at all — the surest cut. Devices treat the symptom; prevention removes the cause.
Two ways to clean a city's air:
- The power plant fits scrubbers and every car gets a catalytic converter — the exhaust is far cleaner, though the coal and petrol still burn.
- Meanwhile the city adds solar power, better insulation, and buses — so less fuel burns at all.
- The first cleans the smoke; the second means there's less smoke to clean.
Air pollution is cut by cleaning exhaust and by preventing it. Catalytic converters clean car exhaust; scrubbers strip sulfur dioxide and filters catch particulates at smokestacks. Governments set limits through laws. The surest cut is prevention — using less energy and switching to renewables, so the pollution is never made.