Les émissions de ce véhicule polluent trop.

Les émissions means the emissions.

French nouns need an article more often than English nouns do, so French uses les here where English also uses the.
A few useful details:

• émission is a feminine noun
• émissions is plural
• so the article is les = the for plural nouns

So:

• l’émission = the emission
• les émissions = the emissions

In this sentence, les émissions is the subject of the verb.

It is plural because French is talking about the vehicle’s emissions as a whole, not just one single emission.

This is very natural in both French and English:

• les émissions = the emissions
• not l’émission = the emission

Because the subject is plural, the verb must also be plural later in the sentence: polluent.

De ce véhicule means of this vehicle or, more naturally in English, from this vehicle / this vehicle’s.

So the structure is:

• les émissions = the emissions
• de ce véhicule = of this vehicle

Together:

• les émissions de ce véhicule = this vehicle’s emissions

French often uses de where English might prefer an apostrophe:

• les émissions du véhicule = the vehicle’s emissions
• les émissions de ce véhicule = this vehicle’s emissions

French uses:

• ce before most masculine singular nouns
• cet before masculine singular nouns that begin with a vowel sound
• cette for feminine singular nouns

Since véhicule is masculine singular and starts with a consonant sound, French uses ce:

• ce véhicule = this vehicle

Compare:

• cet avion = this plane
• ce véhicule = this vehicle
• cette voiture = this car

The verb is polluent because the subject is les émissions, which is third-person plural.

The infinitive is polluer = to pollute.

Present tense:

• je pollue
• tu pollues
• il/elle pollue
• nous polluons
• vous polluez
• ils/elles polluent

Since les émissions is like elles, the correct form is polluent.

Not fully. In French, the ending -ent in the ils/elles form is usually silent.

So polluent is pronounced roughly like pollu.

That means these sound the same:

• il pollue
• ils polluent

The difference is visible in writing, but not usually heard in pronunciation unless the context makes it clear.

Trop means too much or too many, and in this sentence it modifies the verb polluent.

French often places adverbs like trop after the verb:

• polluent trop = pollute too much

This is different from English, which may sound more natural as:

• pollute too much
• are too polluting is possible in English, but that is a different structure

So the French sentence is built like this:

• subject: Les émissions de ce véhicule
• verb: polluent
• adverb: trop

Yes, but it would not be exactly the same structure.

• Les émissions de ce véhicule polluent trop.
  = The emissions of this vehicle pollute too much.

• Les émissions de ce véhicule sont trop polluantes.
  = This vehicle’s emissions are too polluting.

Both are natural, but they work differently:

• polluent trop uses a verb: polluer
• sont trop polluantes uses être
  • an adjective: polluantes

The original sentence focuses on the action or effect: they pollute too much.

It could, but it would mean something slightly different.

• de ce véhicule = of this vehicle / this vehicle’s
• du véhicule = of the vehicle

So:

• Les émissions de ce véhicule polluent trop.
  = The emissions of this vehicle pollute too much.

• Les émissions du véhicule polluent trop.
  = The emissions of the vehicle pollute too much.

The first points to this vehicle specifically. The second means the vehicle.

Mostly yes. Véhicule is a general word for a vehicle, just like in English. It can refer to a car, truck, van, and so on.

However, in everyday speech, French speakers often use a more specific word if they know what kind of vehicle they mean:

• voiture = car
• camion = truck
• moto = motorcycle

So véhicule is correct and natural, but slightly general.

The sentence follows a very standard French pattern:

• Les émissions de ce véhicule = subject
• polluent = verb
• trop = adverb

So the order is:

Subject + verb + adverb

That makes this a very useful model sentence for learners, because the structure is straightforward and common in French.