Companies and institutions employing foreigners in China are starting to realize that to keep workers in the cities, they need to make changes to the way they operate. Based on anecdotal evidence, air pollution, more than anything else, is driving expatriate workers away from China, or dissuading those outside China from taking postings here. News reports of various rounds of  “airpocalypse” descending on Chinese cities have not helped. In response, some employers are handing out hardship bonuses. Others are allowing employees more vacation or work time outside the country. In recent months, the United States Embassy in Beijing has come up with its own strategy to blunt the hazards and the fears that come with Chinese smog: It has ordered thousands of air purifiers for the homes of employees from the United States. Blueair, the Swedish company that is filling the embassy order, said the purchase was among the largest from China. “This is an important order,” said Jonas Holst, international sales manager for Blueair.

“It’s absolutely in the top end.” Anxieties over air quality surged in January, when levels of fine particulate matter during a particularly smoggy spell in northern China reached, in some areas of Beijing, 40 times the recommended exposure limit set by the World Health Organization. air duct advanced cleaningThe United States State Department sent a team of experts to China to evaluate employees’ homes and make recommendations on how to ensure relatively clean air quality indoors. uv air cleaner whole houseAmerican officials concluded they needed to place more air purifiers in frequently used residential spaces, such as bedrooms and living areas, even though new employees already get some units when they first arrive. air duct cleaning florida

(The embassy itself has a centralized air filtration system.) After the team left, the United States government put out a call for proposals, and in the end it decided to go with an American supplier of Blueair products. Some of the Blueair machines have begun arriving in Beijing. The United States Embassy declined to provide official comment on the purchase and did not specify the number of units bought. Mr. Holst also declined to give numbers, but he said the total was somewhere under 5,000 and more than a couple thousand. He also declined to give details on the purchase price. It is safe to assume the price per unit for the embassy order is much less than the retail price in Beijing. Torana Clean Air, an official Blueair seller in the Chinese capital, said its least expensive unit, the 203 model, cost 3,231 renminbi, or about $530. That model is mainly used for bedrooms and offices up to 20 square meters, or 215 square feet. The best-selling larger model, the 503, costs 6,174 renminbi.

There is a top-of-the-line model imported from Sweden that goes for 11,980 renminbi, but sales of that are rare. Most Blueair units are made for export in Shenzhen, in southern China. Prices of Blueairs vary around the world because of taxation, import duties and transport costs, said Chris Buckley, the head of Torana Clean Air (who is not related to the Chris Buckley who reports on China for The New York Times). Mr. Buckley said he had supplied schools and embassies in Beijing, including those of France, Finland and the Netherlands. Among foreigners, a popular — and pricier — alternative to Blueair purifiers are those from IQAir, a Swiss company. Other brands are edging into the market, given the growth prospects in China. Some medical experts have tried to give their assessments of the models. Among them is Dr. Richard St. Cyr, a doctor at Beijing United Family Hospital who writes a health blog and a column for the Chinese site of The Times. In his estimate, Blueair performs well in tests against other brands.

Mr. Holst said Blueair had had a “significant” increase in revenue from China sales in the last 12 to 15 months, though he declined to give numbers. The biggest revenues are from Beijing and Shanghai, he said, though Blueair has a sales presence in 50 Chinese cities. Last week, Gary F. Locke, the American ambassador, announced he would leave his post early next year and return to Seattle. He has been in Beijing a little more than two years, a relatively short period for the job. His announcement prompted widespread speculation that he was fleeing the city’s notorious air. (After all, some Chinese are decamping to rural areas to lead greener lives.) But Mr. Locke told The Los Angeles Times that he was leaving because he and his wife had agreed their children should spend their junior and senior years of high school in the United States. “We are concerned about it,” he said of the air quality, “but that’s not what motivated us to go back.” On Friday and Saturday, the air quality index in the capital, as measured by a device on the rooftop of the United States Embassy, reached the “hazardous” level.

That is when American officials recommend staying indoors, preferably with purifiers on.BEIJING — I RECENTLY found myself hauling a bag filled with 12 boxes of milk powder and a cardboard container with two sets of air filters through San Francisco International Airport. I was heading to my home in Beijing at the end of a work trip, bringing back what have become two of the most sought-after items among parents here, and which were desperately needed in my own household.China is the world’s second largest economy, but the enormous costs of its growth are becoming apparent. Residents of its boom cities and a growing number of rural regions question the safety of the air they breathe, the water they drink and the food they eat. It is as if they were living in the Chinese equivalent of the Chernobyl or Fukushima nuclear disaster areas.Before this assignment, I spent three and a half years reporting in Iraq, where foreign correspondents talked endlessly of the variety of ways in which one could die — car bombs, firefights, being abducted and then beheaded.

I survived those threats, only now to find myself wondering: Is China doing irreparable harm to me and my family?The environmental hazards here are legion, and the consequences might not manifest themselves for years or even decades. The risks are magnified for young children. Expatriate workers confronted with the decision of whether to live in Beijing weigh these factors, perhaps more than at any time in recent decades. But for now, a correspondent’s job in China is still rewarding, and so I am toughing it out a while longer. So is my wife, Tini, who has worked for more than a dozen years as a journalist in Asia and has studied Chinese. That means we are subjecting our 9-month-old daughter to the same risks that are striking fear into residents of cities across northern China, and grappling with the guilt of doing so.Like them, we take precautions. Here in Beijing, high-tech air purifiers are as coveted as luxury sedans. Soon after I was posted to Beijing, in 2008, I set up a couple of European-made air purifiers used by previous correspondents.

In early April, I took out one of the filters for the first time to check it: the layer of dust was as thick as moss on a forest floor. I ordered two new sets of filters to be picked up in San Francisco; those products are much cheaper in the United States. My colleague Amy told me that during the Lunar New Year in February, a family friend brought over a 35-pound purifier from California for her husband, a Chinese-American who had been posted to the Beijing office of a large American technology company. Before getting the purifier, the husband had considered moving to Suzhou, a smaller city lined with canals, because he could no longer tolerate the pollution in Beijing. Every morning, when I roll out of bed, I check an app on my cellphone that tells me the air quality index as measured by the United States Embassy, whose monitoring device is near my home. I want to see whether I need to turn on the purifiers and whether my wife and I can take our daughter outside.Most days, she ends up housebound.

Statistics released Wednesday by the Ministry of Environmental Protection revealed that air quality in Beijing was deemed unsafe for more than 60 percent of the days in the first half of 2013. The national average was also dismal: it failed to meet the safety standard in nearly half the days of the same six-month period. The environment minister, Zhou Shengxian, told People’s Daily, the Communist Party mouthpiece, that “China’s air quality is grim, and the amount of pollution emissions far exceeds the environment’s capacity.”I want my daughter to grow up appreciating the outdoors — sunsets and birdcalls and the smell of grass or the shape of clouds. That will be impossible if we live for many more years in Beijing. Even with my adult-size lungs, I limit my time outdoors. Though I ran on the banks of the Tigris River while in Baghdad and competed in two marathons before moving to China, I am hesitant about doing long-distance training for that kind of race here.One thing I refuse to forgo is biking, even if it means greater exposure to hazardous air than commuting by car or subway.

Given the horrendous traffic here — itself a major contributor to the pollution — I go to the office and restaurants and my courtyard home in Beijing’s alleys on two wheels. This winter, I bought a British-made face mask after levels of fine particulate matter hit a record high in January in some areas — 40 times the exposure limit recommended by the World Health Organization. Foreigners called it the “airpocalypse,” and a growing number are leaving China because of the smog or demanding hardship pay from their employers. One American doctor here has procured a mask for his infant son. My mask of sleek black fabric and plastic knobs makes me look like an Asian Darth Vader. Better that, though, than losing years of my life.THIS spring, new data released from the 2010 Global Burden of Disease Study, first published in The Lancet, revealed that China’s outdoor pollution contributed to 1.2 million premature deaths in 2010, or 40 percent of the worldwide total. Another study, published by a prominent American science journal in July, found that northern Chinese lived five fewer years on average than their southern counterparts because of the widespread use of coal in the north.

Cancer rates are surging in China, and even the state news media are examining the relation between that and air pollution. Meanwhile, studies both in and outside of China have shown that children with prenatal exposure to high levels of air pollutants exhibit signs of slower mental development and of behavior disorders. Research from Los Angeles shows that children in polluted environments are also at risk for permanent lung damage.In northern China, shades of gray distinguish one day from another. My wife and I sometimes choose our vacation destinations based on how much blue we can expect to see — thus a recent trip to Tuscany and the Amalfi Coast. I will never take such skies for granted again. “We still can’t get over how blue the skies are here,” the wife of an American diplomat told me over dinner in Georgetown more than half a year after the couple had moved back to Washington from Beijing.Food safety is the other issue weighing on us. We have heard the stories of rat meat being passed off as lamb at hotpot restaurants, cooking oil being recycled and crops being grown in soil polluted by heavy metals or wastewater from factories.

The food catastrophe that most frightened both Chinese and foreign parents was the milk scandal of 2008, in which six babies died and at least 300,000 children fell ill after drinking milk products tainted with melamine, a toxic chemical. Since then, many parents of newborns have gone to great lengths to bring into China foreign-made infant milk powder when it is needed to supplement breast-feeding. Months after my trip back from San Francisco, my wife and I realized that our supply of formula was dwindling. We sent e-mails to friends we thought might be traveling soon to China, asking for volunteers to be “mules.” Our friend Alexa flew in from New York this week with two boxes of powder. We have two other friends who promise to bring more this summer.I recently spoke to a woman in Beijing, Zhao Jun, who pays Chinese students and housewives living in Europe to mail her cans of Cow & Gate, a British brand. “We’re constantly worried, so we want to find a good brand from overseas with a long history,” she said.

So widespread is the phenomenon of Chinese buying milk powder abroad that it has led to shortages in at least a half-dozen countries. Hong Kong has even cracked down on what customs officials call “syndicates” smuggling foreign-made powder to mainland China.The anxieties do not end with milk. Our daughter has begun eating solids, so that means many more questions for us about how we source our food. Do we continue buying fruits and vegetables from the small shops in the alleys around our home? Do we buy from more expensive stores aimed at foreigners and wealthier Chinese? Do we buy from local organic farms? Last weekend, I went with a friend to visit a village home an hour’s drive northeast of Beijing. He and his wife wanted to lease it as a weekend house, but I was more interested in gauging whether I could use the garden to grow our own vegetables. Some people I know here have done that. “It’s so difficult to protect yourself on the food issue,” said Li Bo, a proponent of communal gardening and a board member of Friends of Nature, an environmental advocacy group.