Low air warning sound added.

低空气警告声音补充。

youdao

No organizations or individuals may use the same frequency or the same acoustic signals as those specially used by the State for civil air defense communications or air defense warning.

国家用于人民防空通信的专用频率和防空警报音响信号，任何组织或者个人不得占用、混同。

youdao

Britain faces fine for air quality after final warning from EU 03 Jun 2010

@在欧盟（EU）的最后警告之后，英国面临的是更好的空气质量 2010年6月3日

youdao

Color Red is no substitute for an Iron Dome defense system, but with as little as 15 seconds between an air defense warning and a rocket striking its target, Color Red offers a little bit of extra time for users to find shelter.

FORBES: Rockets Coming Down On Your Head? There's An App for That

And finally, a word of warning: the air will almost certainly be tinged a delicate shade of nicotine blue.

BBC: Prague��s historic coffeehouses

Air-traffic controllers are warning that the furloughs could force them to reduce the rate of flights arriving at big airports like Chicago's O'Hare International and Miami International by a third to a half during peak periods or bad weather.

WSJ: Airlines Dispute Planned Air-Controller Cuts