Word of the Day: air quality (n)

彰化縣埤頭鄉中和國小
The school shows a flag every morning to tell students about the air quality. 學校每天早上會掛旗子告訴學生當天空氣品質。
The teacher is taking out a yellow flag to show that the air quality is okay. 這位老師拿出黃旗表示空氣品質普通。