How much should a person be compensated to breathe China's polluted air? If you're an expatriate employee of Coca-Cola, the answer is a 15 percent bonus, according to a report last week in the Australian Financial Review. (Local Chinese are excluded from the bonus, despite breathing the same air.) Is offering an "environmental hardship allowance" enough for multinational companies in China to retain expatriate employees?

A reasonable person might look at the health risks associated with living in China — and Beijing, especially — and conclude that no sane person would take that deal. On some days the air pollution is 25 times worse than what's considered safe in the U.S., deaths from lung cancer have risen 465 percent over the last three decades, and a recent study showed that Beijing residents can expect to spend significant periods of their life infirm. Many Chinese residents have grown so pollution-aware that they check air-quality rating apps before they check the weather when they wake in the morning, and they converse knowledgeably about air purifiers and masks.

Unsurprisingly, expatriates are quietly leaving China's biggest cities, with many blaming the pollution and its effects on their children. Everyone, it seems, knows someone who has moved away. I recently left after almost 12 years in Shanghai, and my own departed acquaintances include a physician, a journalist and an intellectual-property lawyer. For corporate human-resources managers, the pollution issue affects retention and attraction of quality new hires. Who, after all, wants to take a job in a place that the previous holder abandoned because it was harming their kids?