China air pollution: 'Slightly polluted' or 'hazardous'?

This photo shows two images of the view from CNN's Beijing Bureau, one from a blue sky day and one from a polluted day.

Story highlights

  • China rated Beijing air 'slightly polluted' that U.S. standards rated 'hazardous' this week
  • Beijing officials use equipment from the U.S. to monitor air quality, but standard is lower
  • Public complaints over Beijing's worsening air quality on microblogs are common
  • Government has put environmental protection as a priority in its latest 5-year plan
As I type this week's column, I look out of my office window and stare at a depressing sight. A heavy blanket of smog and dust hangs over the sky. Buildings nearby are barely visible. Air is barely breathable.
I checked the website of the China National Environmental Monitoring Center. It rated Beijing's air quality for the day as "slightly polluted".
On Twitter, however, the U.S. Embassy's BeijingAir, an air-quality monitoring app, rated the air pollution level as "hazardous."
What gives?
I visited the Beijing Municipal Environmental Monitoring Center (BMEMC) to find out. "We've been using equipment imported from the U.S. to monitor air quality ever since we set up in 1987," Vice Director Hua Lei tells me. "We use the same techniques as the American system."
But there is one difference: the Chinese monitoring stations measure particulates 10 micrometers or smaller, a standard known as PM10.
CNN's Beijing Bureau Chief Jaime FlorCruz looks out on Beijing's pollution on November 16.
This photo, taken from CNN's Beijing Bureau in September, shows the city on a blue sky day.