In air-quality reports, PM2.5 refers to

particles larger than 2.5 millimetresCorrect answerYour answer2.5 parts per million of ozoneCorrect answerYour answerfine particles 2.5 micrometres or less across, which can reach deep into the lungsCorrect answerYour answerair that is 2.5 times cleaner than normalCorrect answerYour answer

Show the answer and explanation

CorrectNot quiteAnswer C

Correct answer: C

PM stands for particulate matter; the number is the largest particle size in micrometres.
PM2.5 particles are about thirty times thinner than a human hair and pass deep into the lungs and even the blood.

Concept: Particulate matter
Typical timeTypical: 60 s
Your timeYours: —

The rule this testsAir, water, soil and noise pollution

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In air-quality reports, PM2.5 refers to

Explanation