今天空气怎么样？十年前，美国驻华大使馆的空气监测仪提供北京唯一透明、实时的PM2.5数据，当时监测仪记录到的污染水平比以往任何时候都要高，这导致空气质量读数被标为“crazy bad”（“糟糕透顶”）。自那时以来，情况已有了显著改善。致更清洁的空气和更良好的健康！

How’s the air today? Ten years ago, Embassy air monitors providing the only transparent, real-time PM2.5 data in Beijing recorded pollution higher than ever before, causing an air quality reading labeled “crazy bad.” Things have improved remarkably since that time. Here’s to cleaner air and better health!

出处：美国驻华大使馆（微信公众号：USEmbassyChina）