Hong Kong’s core business and shopping districts of Central, Causeway Bay and Mong Kok were enveloped in dangerously high air pollution levels for a combined total of more than 184 days last year, according to research by Friends of the Earth.
It was the worst year recorded since the air pollution index (API) was introduced 18 years ago.
The environmental group went through the API data for 2013 and found there were 184 days when the index recorded at roadside air monitoring stations in the three districts was above the 100 level specified as harmful.
That compares with 142 such days in 2012 and 172 days in 2011.
The worst-hit district was Central, where on 83 days last year the index topped 100, compared with 54 days in 2012.
The number of days with roadside API over 100 in Causeway Bay and Mong Kok was 61 and 40, respectively.
Friends of the Earth environmental officer Adrien Chen Kam-cheuk urged the government to speed up the introduction of electronic road pricing to discourage traffic entering Central.
“It is obvious that heavy traffic is to blame for Hong Kong’s worsening roadside air pollution,” Chen said. “With the wall effect because of the high-rise buildings, air pollutants are difficult to disperse.
“We believe the government should not drag its feet in introducing electronic road pricing to manage traffic flow in Central,” Chen said.
Last week, Secretary for Transport and Housing Professor Anthony Cheung Bing-leung said the government would consider a pilot scheme for electronic road pricing to manage traffic after completion of a bypass in 2017 linking Wan Chai and Central.
Public consultation on the scheme could start in 2016. But Chen said it would be too late.
According to the group’s research, the number of days on which roadside stations recorded air pollution index levels over 100 increased from 51 in 1999 to 102 in 2009, and 184 in 2013.
The API converts air pollution data into a value ranging from 0 to 500. Between 2005 and 2011 there were about 20 days a year when the API made it above 100.
In December last year, the Environmental Protection Department replaced the API with a new Air Quality Health Index.
The new system measures the short-term health risks of air pollution by analysing the three-hour average concentrations of four major pollutants – ozone, nitrogen dioxide, sulphur dioxide and particulate matter (PM10 and PM2.5).