一次污染物又称“原生污染物”。由污染源直接或间接排入环境的污染物。如排入洁净大气和水体内的化学毒物、病毒等。是环境污染的主要来源。
造成9月9日夜间20：00～23：00一次污染物NO、CO和SO_2浓度急剧升高的原因是由于夜间稳定情况下，大气的垂直扩散减弱，污染物在底层积累造成的。
The cause for increasing of NO, CO and SO_2 concentration during 20: 00 ~ 23: 00 on September. 9 of 2001 is due to weak vertical diffuse and pollutants accumulated at low atmosphere in the night.
我们的皮肤在不停地剥落——每个人每两到四周就会更换一次表层皮肤——而所有那些脱落的皮肤可以帮助减少室内环境中的某些污染物含量。
We shed skin constantly — each of us replacing our outer layer of skin every two to four weeks — and all of those skin flakes may help reduce levels of certain pollutants in indoor environments.
目前，污染物测量是在一个城市的多个不同地点进行测量的，然后数据会合计成一个数字(空气质量指数)最后在网站上每天发布一次。
Currently, pollutants are measured at different stations in a city and that data is aggregated to a single number (the air quality index) and published once a day on a website.
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