And now, we're going to show you video of something happening right now that has hundreds of millions of people buying masks and hiding inside. The chinese are in the throes of what reporters are... See More
And now, we're going to show you video of something happening right now that has hundreds of millions of people buying masks and hiding inside. The chinese are in the throes of what reporters are calling air-pock lips. And abc's gloria riviera is truly there in the thick of it all. Reporter: The sun was shining in beijing today, but you wouldn't know it. You feel a little bit suffocated. Reporter: This could be my long, tweeted one chinese resident. And time lapse photos show how chemical clouds made buildings disappear. Zero wind, freezing temperatures and factories at full tilt, made this week a perfect storm for pollution. At its peak, pollution hit 755 in beijing, making breathing extremely has dar douse. By comparison, the worst polluted city in the u.S., bakersfield, california, hit a high of 159 last year. It's super toxic air. Particle pollution like that can cause heart attacks and strokes that can kill people. It's lethal. Reporter: This photo from a recent greenpeace study shows what an air filter looks like after just 24 hours in beijing. Watch my wipe a thin layer that's accumulated on most cars. That's soot and grime. And this is my own air purifier. Watch this. Look. That's what we're breathing in beijing. One expert told me it's like becoming an instant smoker. Beijing did issue emergency warnings, for the first time ever this year. Signs the gott can't avoid problems everyone can see. Gloria river verve ya, abc news, beijing. And another note about this. When our team visited china two years ago, we noticed the difference between the polluted air outside in beijing and how we felt when we walked inside the american embassy, where the air is much cleaner. Well, we were told that the pollution is so severe there, because of health issues, the embassy creates special filtered air for embassy workers. So, they'll have air as clean as the air here back home.
This transcript has been automatically generated and may not be 100% accurate.