Roadside air-pollution levels hit a two-year high in some parts of Hong Kong this week, obscuring the city’s vistas in a sea of white haze and prompting the government to warn the young, the elderly and people with heart or respiratory illnesses to stay inside.

Hong Kong’s sky is typically bluer and cleaner in the summer months than in the rest of the year, as winds from the south blow in fewer pollutants and strong sea breezes offer relief, dispersing the dirty air. This week, though, the air was heavy with smog, as a nearby typhoon created a weather system that trapped pollutants and helped condense them, causing them to sink. At 7 a.m. on Thursday, roadside monitoring stations in the city’s Central district recorded air-pollution index readings of 212, an extreme not seen in the area since dust storms hit Hong Kong in March 2010, bringing with them a cloud of noxious air.

via Hong Kong’s Dirty Air is Worst in Two Years – China Real Time Report – WSJ.