HONG KONG: The city's air-conditioned buses are causing temperatures to soar in Hong Kong and making passengers more prone to illness, according to a study by environmental protection group Green Sense.

The average temperature of the heat emitted from 64 air-conditioned buses checked by the green group was 37.8 degrees Celsius. The highest temperature recorded 47.1 degrees, about 13 degrees higher than the temperature on the street.

In comparison, the heat emitted from five non-air conditioned buses checked by the group were only 0.5 to three degrees higher than street temperature.

"This proves that air-conditioned buses are the major cause of soaring temperature in the city," said Gabrielle Ho Ka-po, project manager.

Meanwhile, the temperature inside air-conditioned buses was found to be extremely low, indicating that energy is wasted.

Those included in the list of "freezing buses" were mainly from Kowloon Motor Bus (KMB). A KMB bus on route 251M was the coldest with temperature of 17.7 degrees on the upper deck.

The situations inside the buses of Citybus Limited and New World First Bus Service Limited were acceptable, although a Citybus on route 7 recorded the second-coldest temperature, said Ho.

University of Hong Kong mechanical engineering professor Dennis Leung Yiu-cheung said air conditioners on the buses could be 40 to 60 times more powerful than those used in households.

"The pedestrians will suffer from the unbearable heat because of the buses," he said.

Hong Kong Medical Association vice-chairman Alvin Chan Yee-shing warned patients of asthma and allergic rhinitis not to take such buses, as their illnesses are more likely to occur when there is a drastic change of temperature.

The filtering system inside the buses may not help prevent the spread of gems, Chan said.

A spokeswoman of KMB surnamed Sin declined to comment on the study by Green Sense, as she was not clear about how it was carried out.

She said the air-conditioning systems on their buses automatically maintain the temperature between 22.5-25.5 degrees.

(HK Edition 07/21/2009 page1)