TOM FRIEDMAN WAS UNAVAILABLE FOR COMMENT: China’s Pollution Problem Is Visible From Space. “World Health Organisation guidelines suggest that PM2.5 levels above ten micrograms per cubic metre are unsafe. The boffins have found (as the map shows) that almost every Chinese province has levels above that. Indeed, much of the country’s population endures air so foul that it registers above 30 on the PM2.5 scale, with Shandong and Henan provinces topping 50. Because these readings reflect the average pollution that a typical resident in a province is likely to endure during a given year, they underplay the sharp spikes in pollution that are seen on particularly dirty days, when spot readings go much higher. That is why Beijingers should take little comfort from the fact that the capital’s pollution measures only 35.”