Learn Hardcore Korean: gonghangeseoneun heubyeoneul mos haeyo.

에서 marks the place where an action happens (“at/in” for activities).
는/은 is the topic particle; here it makes “as for at the airport” and often implies contrast (e.g., “At the airport, you can’t smoke (even if elsewhere you might)”).
Without 는, 공항에서 흡연을 못 해요 is also correct, just less contrastive.

Can I use 공항에 instead of 공항에서? What’s the difference between 에 and 에서?

에: location of existence or destination (used with verbs like 있다/없다, 가다/오다).
에서: location where an action/event occurs.
Smoking is an action, so you need 공항에서, not 공항에.

Is 공항에서는 the same as 공항에선?

Yes. 에선 is the contracted form of 에서는. It’s common in speech and informal writing; both are correct.

Why is there a space in 못 해요? Is 못해요 wrong?

When 못 is the adverb “cannot,” write it separately from the verb: 못 가요, 못 먹어요, 못 해요.
In the fixed pattern -지 못하다, it’s written together: 하지 못해요, 피우지 못해요.
You’ll see 못해요 informally, but as a learner, prefer the spaced form when it’s just 못 + verb.

What nuance does 못 convey here compared to 안?

못: inability due to external factors (rules, time, skill), often read as “can’t/aren’t allowed to.”
안: deliberate choice/refusal, “don’t/won’t.”
So 공항에서는 흡연을 못 해요 suggests a rule; 공항에서는 흡연을 안 해요 sounds like “I don’t smoke at the airport (by choice).”

Why use the formal noun 흡연 instead of 담배(를) 피우다?

흡연 is a formal Sino-Korean noun meaning “smoking,” common in signs/official contexts (e.g., 금연, 흡연 구역).
Everyday speech prefers the verb phrase 담배(를) 피우다.
Alternatives:
- 공항에서는 담배(를) 못 피워요.
- Clear prohibition: 공항에서는 담배 피우면 안 돼요.

Is 흡연을 못 해요 natural?

It’s grammatical and fine, especially in neutral/formal contexts.
For very natural conversation, many would say:
- 공항에서는 담배 못 피워요.
- 공항에서는 담배 피우면 안 돼요.
- Signs/announcements: 공항은 금연 구역입니다. / 흡연 금지입니다.

Why does 흡연 take 을? Can I drop it?

With N + 하다, the noun often acts like a direct object, so 을/를 is common: 흡연을 하다, 운동을 하다.
You can drop 을/를 in casual speech: 흡연 못 해요 is acceptable, though many prefer 흡연은 못 해요 or keep 을 for clarity/formality.

Does this sentence mean “not allowed” or literally “cannot”? What should I use for rules?

In context, 못 해요 often implies “not allowed.”
To state prohibition explicitly, use:
- -(으)면 안 돼요: 공항에서는 담배 피우면 안 돼요.
- Formal: 금지예요/금지입니다, 금연 구역이에요/입니다.

How else could I phrase it using 할 수 없다 or -지 못하다?

What politeness/register is 해요, and what are the other levels?

Why is it 는 (not 은) after 공항에서?

은/는 selection depends on the final sound of the preceding word. 공항에서 ends in a vowel sound, so use 는. If it ended in a consonant, you’d use 은.

Can I change the topic to emphasize the activity instead of the location?

Yes:

흡연은 공항에서 못 해요. “As for smoking, you can’t do it at the airport.”
Changing what takes 은/는 shifts the emphasis (place vs. activity) without changing the core meaning.

Pronunciation tips?

공항에서는: often contracted in speech to 공항에선; rhythm like “gong-hang-eh-seon.”
흡연: pronounced close to “heu-byeon” because ㅂ links forward and palatalizes.
못 해요: pronounced “mo-tae-yo”; the final ㅅ in 못 is [t] and it becomes aspirated before ㅎ.

What vocabulary around no-smoking should I know?