(CNN) -- 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."
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China rated Beijing air 'slightly polluted' that U.S. standards rated 'hazardous' this week
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Beijing officials use equipment from the U.S. to monitor air quality, but standard is lower
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Public complaints over Beijing's worsening air quality on microblogs are common
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Government has put environmental protection as a priority in its latest 5-year plan
Despite efforts to limit the number cars with an auto-plate lottery, it's estimated that @placeholder now has over 5 million cars, up from about 3.5 million in 2008.