Hong Kong roadside air pollution reached the worst levels in more than two years as a typhoon that passed through Taiwan brought hot weather and trapped pollutants, prompting a government health warning.

The Air Pollution Index was “very high” at the roadside-monitoring station in Central, Causeway Bay and Mongkok as of 2 p.m. local time, according to the city’s Environmental Protection Department. The reading in Central reached the “severe” level earlier at 212, the highest since March 23, 2010.

Typhoon Saola grounded flights and closed businesses in Taiwan as winds and rain lashed the island. Hong Kong was influenced by the outer layer of the storm as the heat and weak winds resulted in higher ozone levels, trapping the pollutants in the city, the government said in a statement on its website yesterday.

“The weather conditions only exacerbate the situation,” Erica Chan, campaign manager at Clean Air Network, said in a release yesterday. Vehicle exhaust fumes in the city are “the real root of this problem,” she said.

The levels of fine suspended particulates reported in the 24-hour period from July 31 to Aug. 1 surpassed the World Health Organization’s recommended Air Quality Guidelines, Clean Air Network said.

Heart Illnesses

The Hong Kong government advised people with respiratory or heart illnesses, the elderly and children to avoid heavy- traffic streets and reduce physical activities when the pollution indicator is at the “very high” level.

Hong Kong’s polluted air causes more than 3,000 premature deaths a year, according to the Civic Exchange. The research group said in a statement on Jan. 12 that 49 million doctor visits “can be attributed to Hong Kong’s persistently poor air quality” since 2005.

New York, London, Tokyo and Singapore all have better air quality and more ambitious improvement targets, according to World Health Organization data and the city governments’ websites.

Hong Kong’s average reading of particulate matter with a diameter of 10 micrometers -- about 1/7th the width of a human hair -- or less in 2009 was 50 micrograms per cubic meter, according to a WHO survey of 1,100 cities. While that was less than half Beijing’s, it compares with 29 in Singapore and London, 23 in Tokyo and 21 in New York.

To contact the reporter on this story: Simon Lee in Hong Kong at slee936@bloomberg.net

To contact the editor responsible for this story: Hwee Ann Tan at hatan@bloomberg.net