Most polluted day of the year, and more of the same to come
Hong Kong recorded its highest pollution reading of the year yesterday with roadside stations in urban areas recording very high levels of smog.
Yesterday's roadside air quality was the worst so far this year, but the month of February was a lot less dirty than the same month a year ago.
Excluding yesterday, Hong Kong had 22 hours of very high pollution readings for the month - when the API was over 100 - at the three roadside air quality monitoring stations, compared to 198 hours last year.
The API surged to 141 at Causeway Bay roadside station yesterday, 136 in Central and 113 in Mong Kok.
The dominant pollutant at street level is nitrogen dioxide, which comes from vehicle exhausts.
The reading meant the pollution level was very high with people suffering from respiratory or heart illnesses advised to stay indoors or avoid prolonged stay in roads and streets with heavy traffic.
The Environmental Protection Department's spokesman said the very high API readings were a result of a build-up of local pollution because of light winds, coupled with the influence of high regional air pollution.
'We expect that the regional background air pollution will continue to be high and that air dispersion will remain poor in the next couple of days,' the spokesman said.