Grammar
N(으)로 인해
Meaning
AdvancedN(eu)ro inhae
A formal written way of giving a cause, meaning 'because of N'. It attaches to a noun, not to a verb ending, so the cause has to be expressed as a noun (폭우로 인해, 공사로 인해). Use 인해 before a verb and 인한 before a noun: 폭우로 인한 피해 is 'damage caused by heavy rain'. 이로 인해 is the fixed form meaning 'because of this', pointing back at the whole situation just described, and 이로 인한 does the same in front of a noun. All of these belong to newspaper and report Korean; in conversation you would hear 때문에 instead.
Form
Noun + 로 인해 after a vowel or after ㄹ (폭우로 인해, 산불로 인해), and 으로 인해 after any other consonant (지진으로 인해, 사건으로 인해). The two shapes come from the verb 인하다 ('to be due to'): the -아/어 form 인해 modifies a verb, and the modifier form 인한 sits in front of a noun (지진으로 인한 피해). 이로 인해 uses 이, the pronoun standing for the situation just mentioned, so it opens the clause or sentence that follows instead of naming a cause with its own noun. It cannot attach to a verb ending — to feed a clause in, nominalise it first with -(으)ㄴ/는 것 (값이 오른 것으로 인해) or switch to -기 때문에.
Examples
폭우로 인해 기차가 한 시간 늦게 도착했습니다.
Due to the heavy rain, the train arrived an hour late.
지난주 폭우로 인한 피해가 아직 남아 있습니다.
The damage caused by last week's heavy rain still remains.
공사로 인해 이 길은 다음 달까지 막힙니다.
Due to construction, this road is blocked until next month.
값이 크게 올랐습니다. 이로 인해 손님이 줄었습니다.
Prices rose sharply. Because of this, the number of customers fell.
Common mistakes & nuance
Choosing between 인해 and 인한 is decided by what comes next, not by meaning: a verb takes 인해, a noun takes 인한. 폭우로 인해 피해 and 폭우로 인한 발생했습니다 are both wrong. Also note that 이로 인해 needs a preceding sentence to point at, so it cannot open a text. Because the form is heavy and formal, it sounds odd in everyday speech — say 비 때문에 늦었어요, not 비로 인해 늦었어요, when talking to a friend.
Similar grammar
- 때문에
때문에 covers the same 'because of' meaning but is at home in speech as well as writing, and with -기 때문에 it can take a whole clause. N(으)로 인해 takes a noun only and stays in formal written Korean, which is why news reports prefer it.
- -(으)로
Plain -(으)로 already marks a cause on its own (폭우로 늦었습니다), and 인해 is what turns that into an explicit, formal statement of cause. Adding 인해 does not change the meaning so much as raise the register and make the causal link unmistakable.