The official line is that Locke is returning to Seattle so he can be with his high-school age children when they graduate in the U.S. “It’s very clear his family has been back there since summer, his eldest kids are in high school, and he wants to rejoin his family,” said the spokesman for the U.S. Embassy in Beijing, Nolan Barkhouse.

Locke himself responded to rampant speculation across social media that pollution forced him out. “Absolutely not,” he told the Los Angeles Times. “We are concerned about it [air quality], but that’s not what motivated us to go back.”

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The real story is probably not so clear-cut. Other media outlets have reported that people who spoke to Locke about his decision said that pollution weighed on his resignation. And Locke himself acknowledges at least some concern in his quote.

Locke’s resignation follows a trend I’ve heard for the past few weeks as I’ve asked businesspeople and others in Beijing about pollution’s influence on their decisions to live here, questions I’ve had ever since moving to China’s capital city this year. Invariably, they say pollution is a top factor, especially for those with children, and it’s something that has real influence on those who have a choice about living in China.

One prominent headhunter in Asia I spoke with this week said in the corporate world, there’s a shortage of executives for CEO roles who want to come to China. Sure, the country’s luster has slightly worn off — there are no longer eye-popping, double-digit GDP growth rates, for one. But the headhunter said it doesn’t matter how much you pay prospective CEOs to come here (or in Locke’s case, how much prestige comes with the job), their decisions often come down to pollution and lifestyle. For some, pollution’s on the top of the list of considerations, for others it’s somewhere in the middle. But it’s an issue for all.

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Public figures like Locke can’t talk about pollution like others. Besides diplomatic considerations, there’s also the fact that China is no longer at loggerheads with the U.S. over the problem. China’s government has not only followed the U.S. Embassy’s lead to issue frequent measures of air quality for the public, but it openly talks about the need to reverse the ugly trend of air quality, even if solutions remain far off.

Locke may never reveal the degree to which pollution affected his decision. But his resignation highlights this truth: Career prestige is one thing, the reality of living in Beijing is another.