It can be put on a tree around your house to test the air quality.

你可以把它放在你房子周围的树上来测试空气质量。

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Safety, along with school test scores, air quality, and affordability, were weighted especially highly in this year's calculations.

其安全性，以及学校测试分数，空气质量，和可负担性，尤其是在今年都被考虑在内了。

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Between August 17 and 20, the Beijing organising committee conducted studies of air quality during test events.

8月17日至8月20日，北京组委会在测试赛期间对空气质量进行了研究。

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The air quality was monitored during last summer's test events in Beijing, with no health problems reported and findings indicating the health of the athletes was not impaired.

BBC: Rogge admits Beijing air concern