PM 2.5

Published: Nov. 22, 2012, 1 p.m.

b'Hong Kong, like all big cities in the world, is engaged in a battle against air pollution.\\xa0On land as well as water, harmful particulate matter, or PM, is being emitted from diesel engines that power vehicles and ships.\\xa0That\\u2019s PM2.5 on Hong Kong Connec...'