早在上世纪70年代以前，纽约中央公园还是一片颓败之象。桥梁摇摇欲坠，柳树也枯萎了。涂鸦和肆意破坏令游乐场和长椅一片狼藉。这种景象会让人不由自主地认为，美好的时光一去不复返了。“正面利用已逐渐被违法活动所取代，”纽约中央公园保护协会（Central Park Conservancy）如此形容道。

后来，乔治索罗斯站了出来。这个知名区域有着160年的历史，但纽约市政府的糟糕管理，却让他和其他人很是懊恼，于是索罗斯和其他金融家委托进行了一项公园修复研究。研究的主要建议是，成立一个由私人组成的委员会，监督公园的运营——实际上，就是允许普通公民控制公园。很快，非盈利组织“中央公园保护协会”成立，这个地区也恢复了昔日的荣光。三十年后，中央公园每年约6,000万美元的预算中，75%都由这个保护协会提供，保护协会本身也成为纽约市赫赫有名的组织之一。协会的理事会成员包括前摩根大通（J.P. Morgan）主席兼CEO威廉哈里森、投资机构KKR的亨利克拉维斯，以及对冲基金经理约翰鲍尔森。鲍尔森在两年前宣布向保护协会捐助1亿美元，成为这座公园收到的最大一笔捐款。

全世界贫富差距的日益扩大，引发了人们对于经济公平和阶级划分的担忧。但中央公园的复兴证明了非常富有的阶层在公民社会中的重要性。他们用自己的钱，为政府不会资助的项目提供资金；而且，他们在城市中心有着特殊的关键地位。所有这些都解释了一个问题：为什么中国空气污染迫使有钱人逃离的消息这么令人忧虑？中国是否因为雾霾而正在失去它最重要的居民？

中国北方城市糟糕的空气状况已经持续有一段时间了。但因为过去几年的“空气末日”和屡屡刷新纪录的PM 2.5水平，中国人越来越不满，越来越多的有钱人开始计划撤离中国。PM2.5是指直径小于2.5微米（人类头发宽度的1/30）的危险的小型污染物，能够进入人类血液，可能导致癌症和呼吸系统疾病。

最近的调查提供了有力证据，证明中国的污染城市可能正面临失去赋予阶层的风险。胡润研究院（Hurun Research Institute）一月份发布的调查显示，64%的中国富人（拥有财富超过160万美元）已经移民或正在计划移民其他国家，而两年前的调查结果为60%。这样的结果连中国年度富豪榜胡润百富（Hurun Report）的创始人胡润自己都大吃一惊。他没想到这个比例在如此高的情况下还会继续增长。他表示，污染和食品安全是移民的第二大理由，排在首位的理由是人们对于安全和财富保障的渴望。虽然移民人数尚未达到临界点，但胡润说：“许多家庭发现其他富裕家庭正在移居海外，”这让他们有了效仿的对象。

By the 1970s, Central Park was in a state of decay. Bridges were crumbling. Meadows had dried up. Graffiti and vandalism blighted playgrounds and benches. There was an overwhelming feeling that its best days had passed. "Positive use had increasingly been displaced by illicit and illegal activity," is how the Central Park Conservancy describes it today.

Then George Soros stepped in. Frustrated by what he and others saw as New York City's inept management of the 160-year-old institution, Soros and another financier commissioned a study on potential fixes. Its chief recommendation was creating a private citizen-based board to oversee an individual running the park's operations -- in effect, allowing private citizens to control the park. Soon the not-for-profit Central Park Conservancy was created, and the area returned to its former glory. Thirty years later the conservancy provides 75% of a nearly $60 million annual park budget and is a New York institution unto itself. The board of trustees includes former J.P. Morgan (JPM) Chairman and CEO William Harrison, KKR's (KKR) Henry Kravis, and the hedge fund manager John Paulson, who two years ago announced he would give $100 million to the conservancy, the largest park donation ever.

The growing wealth gap around the world is raising concerns about economic fairness and class divisions. But Central Park's revival illustrates the importance of the very wealthy in civic society. Their private dollars fund projects that governments won't, and they have an especially key role in urban centers. All this explains why reports of China's air pollution driving out wealthy residents are so troubling. Is China losing its most important residents to smog?

The air in northern Chinese cities has been poor for a while. But after the past few years of "air apocalypses" and record-high levels of PM 2.5, the dangerously small pollutants under 2.5 micrometers in size (1/30 the width of a human hair) that find their way into the bloodstream and have been linked to cancers and respiratory problems, citizens have increased complaints and growing numbers of rich have started making plans to move away.

A recent survey provides the strongest evidence yet that China's polluted cities risk driving away the rich. Released in January by the Hurun Research Institute, the survey shows 64% of China's rich (those with wealth above $1.6 million) were either immigrating to another country or planning to, a rise from 60% in the last poll two years ago. That came as a surprise to Rupert Hoogewerf, founder of the Hurun Report, an annual China rich list. He wasn't expecting the already high figure to grow. He says pollution and food safety was the second-biggest reason for emigrating, after the general desire for security and financial well-being. Although the numbers of those emigrating haven't yet reached a critical mass, Hoogewerf says "a lot of families are finding a lot of other rich families are going overseas," providing examples to follow.