Met One Instruments, Inc. will participate in the 10 year anniversary of the installation of the BAM 1020 at the US Embassy in Beijing this October. Rooftop sensors on U.S. embassies are warning the world about ‘crazy bad’ air pollution By Eli Kintisch Apr. 19, 2018 , 10:00 AM In October 2010, as heavy smog hung over Beijing, the U.S. embassy's Twitter feed said its rooftop pollution sensor had detected “crazy bad” levels of hazardous microparticles. So-called PM2.5 had shot up to about 550 micrograms per cubic meter—a level to which programmers had given the sardonic label because they thought it would never be reached. The undiplomatic language ruffled feathers in Beijing; embassy staff apologized, deleted the tweet, and replaced the label with “beyond index.” Yet that incident and others like it spurred public complaints that eventually elicited more aggressive efforts to tame the pollution. By now, rooftop sensors like those that drew attention to Beijing's pol...