Experts say they have found toxic chemicals in the "pea-soup" smogs hanging over Beijing, Tianjin and surrounding areas in higher concentrations than were found in Los Angeles 60 years ago, official media reported.
A recent report from the Chinese Academy of Sciences (CAS) said "large amounts" of organic nitrogen compounds were detected in Beijing smog in January—the beginning of the smog now being dubbed "airpocalypse."
The smog has returned to choke northern China with heavy and off-the-scale pollution this month too, especially with PM 2.5 particles, which tend to penetrate into the gas exchange regions of the lung.
The report blames the prolonged smog on a combination of intensive coal burning, car emissions, cooking pollutants and a particular weather pattern creating an inversion layer over the low-lying cities.
In Beijing, car exhaust was the biggest contributor to the toxic haze that envelops the capital, according to CAS atmospheric physicist Wang Yuesi.
A Beijing resident surnamed Liu said he believed weather patterns had little to do with the smog, however, because the weather in Beijing this year has been similar to previous years.
"Beijing is wreathed in smog right now," Liu said in an interview with RFA's Mnadarin Service on Tuesday. "We haven't seen anything like it in several decades."
"Usually, the skies are pretty clear during the winter, and the visibility remains until you get the dust storms in the spring."
He said this year's smog could only be the result of severe pollution, not the weather.
"As citizens, we are very worried that this is going to harm our health," Liu said. "I am constantly coughing."
Guangzhou-based rights lawyer Liu Zhengqing said the pollution was the direct result of officials who risked the people's welfare to gain high economic growth figures and good marks on their record.
"The government is basically all about scoring political points," he said. "Even if they know about pollution, they don't care."
"They invest in these prestige projects like skyscrapers, to make it look like they're getting results, but they don't care about drainage, or air pollution," Liu Zhengqing said. "They don't care about things they can't see."
Organic nitrogen particles were found in the deadly photochemical smog that killed more than 800 people in Los Angeles during the 1950s and the famous "pea-soupers" of London.
They can cause coughing, shortness of breath and trigger asthma attacks, and are likely behind a spike in hospital admissions for patients with respiratory diseases in January, in the affected area.
However, CAS said photochemical smog was not currently found in Beijing, because not enough sunlight was getting through to form ozone at ground level, state-run CCTV reported.
Reported by Yang Fan for RFA's Mandarin service. Translated and written in English by Luisetta Mudie.