But many countries do not have public air quality measurement systems.

但许多国家没有公共空气质量测量系统。

The WMO says more than half of counties worldwide have no quality management systems for water.

世界气象组织表示，世界上有一半以上的郡县没有水质管理系统。

More than 220 cities now have air quality monitoring systems and 42 others will have systems in place by the end of this year.

目前，220 多个城市拥有空气质量监测系统，另外 42 个城市将在今年年底前建成。