WSJournal. Beijing Pollution Hits Highs

BEIJING—China's capital endured its worst air pollution in recent memory over the weekend, illustrating the persistent challenge the nation's new leaders face in addressing environmental woes.

Beijing residents were advised to stay indoors this weekend when the capital's pollution level surpassed the top range of the Air Quality Index. The WSJ's Wayne Ma and Sum Yin Kwong of Hong Kong's Clean Air Network talk about dirty air, human health and China.

Officials called for residents to stay home and avoid exercising outside after the murky air darkened the skies over Beijing and surrounding areas beginning Friday.

Beijing for the first time activated a new plan restricting construction and industrial activity, curbing vehicle use by government officials and ordering schools to limit outside activity, said state-run Xinhua news agency. The pollution was expected to linger until Wednesday, Xinhua said.

China's government is under pressure to clean up the country's environmental problems, a legacy of more than three decades of untrammeled economic growth. New Communist Party leader Xi Jinping addressed the issue directly when he took his post in November, citing a "better environment" in a national address as among Chinese citizens' aspirations.

Chinese Officials in recent months have moved to release more air-quality data. In December, the environmental ministry specifically mentioned for the first time its aim to reduce levels of PM2.5—tiny particulate matter—saying it would cut them by 5% each year in major cities and industrial areas through 2015.

Last week, China's National Development and Reform Commission, the country's top economic planning body, said it expanded a pilot program nationwide that offers subsidies to coal-fired power plants that reduce nitrogen-oxide emissions.

Meanwhile, the pollution appeared to peak on Saturday evening, when an air monitor at the U.S. Embassy in Beijing showed an air-quality index reading of 755. The U.S. Environmental Protection Agency says an index reading of above 300 is "extremely rare" in the U.S. and generally occurs only during events such as forest fires.

Pollution Hits Highs in Beijing

The monitor also showed the concentration of PM2.5 reached 886 micrograms per cubic meter on Saturday. That measure is almost 12 times the recommended standard in China and more than 25 times the standard in the U.S. The World Health Organization says chronic exposure to particles in the air contributes to the risk of developing cardiovascular and respiratory diseases, as well as lung cancer.

It wasn't clear when the index last reached a similar level. The U.S. Embassy doesn't release historical data.

Phone calls to China's Ministry of Environmental Protection on Sunday weren't answered, while a person at the Beijing Municipal Environmental Monitoring Center referred questions to a spokesperson who wasn't available.

Zhou Rong, a Greenpeace climate and energy campaigner, and Vance Wagner, a senior researcher at the International Council on Clean Transportation, said stable weather patterns were the likely reason that the pollution had gathered over the weekend. The sources are cars, factories and power plants, they said, with Ms. Zhou adding that record-low temperatures have led to increased burning of coal.

The tainted air shrouded the city in gloom over the weekend, prompting many residents to break out face masks or simply stay indoors. Chris Buckley, owner of the Torana Clean Air Center in Beijing, said he woke up Sunday morning to find 25 emails in his inbox—three times the normal amount for that day—from customers inquiring about masks and air purifiers. "I've received calls from parents and people who have newly arrived in Beijing," he said. He added that he has received more calls from local Chinese customers since the government started stepping up its air monitoring in recent months.

The weekend air quality also prompted a number of comments on China's Twitter-like microblogs, which serve as a national forum in a nation where the media are tightly controlled. "I am really looking forward to hearing what the government will say about this," said Ling Zhijun, senior editor of the People's Daily, the Chinese Communist Party's flagship newspaper, on his account on Sina Corp.'s SINA +1.38% Weibo microblog service. "I especially want to know if the party secretary or the mayor are in Beijing these days. If so, how do they guarantee they can breathe safely in Beijing?"

Despite Beijing's stated efforts to confront environmental issues, it has twice delayed the nationwide rollout of tighter vehicle-emissions standards, as fuel-quality standards have lagged.

The high cost to upgrade refineries to meet tighter fuel-quality standards has generated push back from state-owned oil companies such as China Petrochemical Corp., also known as Sinopec Group, the country's largest refining company by capacity. The committee responsible for fuel-quality standards in China is partly made up of representatives from the refining industry and is chaired by a Sinopec official.

Sinopec began selling higher-quality fuel in Beijing in 2008 and in the cities of Shanghai and Guangzhou in 2010, a company spokesman said on Sunday. It recently started selling similar fuel in Guangdong, Jiangsu and Zhejiang provinces, he said. The spokesman added that the company has spent 200 billion yuan ($32 billion) on improving fuel quality over the past decade.

Meanwhile, Beijing didn't even make it into the top 10 Chinese cities with the worst overall air-quality index, according to the lead story on state-run China Central Television Saturday. CCTV said the worst city was Shijiazhuang, the provincial capital of northern Hebei province, which endured eight consecutive days of "severe pollution."

Most of Hebei is covered in haze, the report said, adding that the four cities with the worst air pollution in China were all located in this province.

Write to Wayne Ma at wayne.ma@dowjones.com