The exhaust produced by the automobile increases the rate of polluted-air-related diseases.

That's my original sentence. Grammarly changed it into "polluted air-related diseases". I think the latter means the diseases are polluted. Which is correct usage?

  • 5
    You need to hyphenate the whole compound 'polluted-air-related'. That produces an adjectival phrase meaning 'related to polluted air'. If you omit the first hyphen you are saying that automobile exhaust produces polluted diseases related to air, which doesn't really make sense, although most people will get the meaning. Grammarly is a not a good source of grammar guidance. May 21, 2023 at 12:20
  • 5
    A more idiomatic phrase is air pollution, not "polluted air". The diseases are related to the pollution, not the air.
    – stangdon
    May 21, 2023 at 13:32
  • 2
    air pollution-related diseases. air pollution without a hyphen is OK. The children, elderly and pregnant women are more susceptible to air pollution-related diseases. who.int/teams/environment-climate-change-and-health/…
    – Lambie
    May 21, 2023 at 18:34
  • 2
    Native US English speaker here. I agree with your usage, but I know other native speakers who go the other way. I agree with the answer suggesting you rewrite the sentence to avoid the problem entirely. May 22, 2023 at 2:53
  • 1
    An en dash may be used: polluted-air–related disease. This is because polluted air has tighter binding than disease.
    – Nayuki
    May 22, 2023 at 5:56

2 Answers 2


Yes, it would be better with both hyphens, but you should take a moment to think "Is Grammarly trying to tell me this is badly written?"

If so, can I rephrase it? Long compound expressions in front of nouns are something to be avoided. The usual way to avoid them is to convert them into a modifying phrase after the noun:

diseases related to air pollution

That is a lot nicer to parse, and it will keep Grammarly happy.

  • Thank you very much!It really inspired me~
    – 庄怀玉
    May 22, 2023 at 13:21
  • 1
    or air-pollution-related
    – Kevin
    May 22, 2023 at 21:37

Just for reference, I believe some style guides call for only inserting a hyphen before "related" in constructions like this. Since there would be a space and not a hyphen between "polluted" and "air" in "diseases related to polluted air", the reasoning is that you don't add one there when you rearrange the sentence. You don't mess with the interiors of the phrases you are rearranging. I am not sure that's the best rule, but I believe some, perhaps most, publishers follow it, hence Grammarly's response.

  • Thank you for your answer. I think what you said is really true because I have observed the hyphen-related problems for many times, and your answer are helpful for me to tackle them.
    – 庄怀玉
    May 23, 2023 at 10:01

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