Usually, the ozone demand varies significantly throughout the cooling season.

通常，新鲜的空气要求在冷却的季节各处重要的改变。

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This is because the city water treatment process has already removed the bacteria present in river or gray water, which reduces the ozone demand.

因为城市水治疗程序有在河中已经移动细菌出现或者使水变灰色，所以这是，减少新鲜的空气要求。

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