Reduction of Air Pollutants
Introduced| English | Meaning |
|---|---|
| catalytic converter/ˌkætəˈlɪtɪk kənˈvɜːtə/ | A device that uses catalysts to convert harmful vehicle exhaust gases into less harmful substances. |
| scrubber/ˈskrʌbə/ | scrubber |
| sulfur dioxide/ˈsʌlfɜː daɪˈɒksaɪd/ | A compound of sulfur and oxygen with formula SO₂, formed in processes such as burning sulfur-containing fuels. |
| particulates/pəˈtɪkjʊleɪts/ | Small solid particles or liquid droplets suspended in air or another fluid. |
| laws/lɔːz/ | laws |
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 turns harmful NO and CO into harmless N2 and CO2
A catalytic converter on a car…
Difficulty 1/5 · 100 coins + a small bonus on first completion today
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…
Difficulty 1/5 · 100 coins + a small bonus on first completion today
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.
Difficulty 1/5 · 100 coins + a small bonus on first completion today
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.
Difficulty 1/5 · 100 coins + a small bonus on first completion today
Burning less fuel is the surest cut — no emissions to clean if they were never made.
Select all ways to reduce air pollution.
Difficulty 2/5 · 140 coins + a small bonus on first completion today
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.