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.
BeijingAir, which reports the reading of an air monitory device installed on the roof of the U.S. embassy building, uses the PM2.5, which measures tiny airborne particulates that cause smog and are deemed more harmful. It ranks air quality from 1 (cleanest) to 500 (dirtiest).
"It measures the very fine particulates which are health concerns, things less than 2.5 micrometers," U.S. ambassador Gary Locke tells CNN's Kristie Lu Stout. "Acceptable range in the U.S. is 35. Here we are near 400, more than 10 times the acceptable level."
That was a few days earlier, when Kristie interviewed the American envoy.
Thursday's reading on BeijingAir: 321.
I have lived in Beijing for nearly 40 years and have seen the air's quality go from bad to worse. I never imagined it to be this bad.
Experts blame the thick haze on rapid urbanization and industrialization. "What come with them are cars, industries and pollution sources from all kinds of directions," says Wu Changhua, China director of The Climate Group, a London-based international organization.
Beijing, for instance, burned some 27 million tons of coal in 2010, according to state-run media. Despite efforts to