Indoor pollution worse than outdoor, HK study reveals

Pollutant levels in Hong Kong have soared to 1,250 percent higher indoors than outdoors, and indoor levels of small-particle pollution, known as PM2.5, are worse than outdoor levels next to some of the busiest roads in the territory, according to a study by Hong Kong Baptist University.
Scientists have revealed that it could be making residents chronically ill, as the level of PM2.5, which can lodge deep into the people’s lungs, was on average nearly 10 percent higher indoors than the highest level found outdoors.
One of the researchers even commented that indoor air pollution from perfumes, cleaning products and cooking fumes have turned the average Hong Kong home into a “mini chemical warehouse”.
A South China Morning Post report stated that the median level of volatile organic compounds (VOCs), carbon-based chemicals that easily evaporate at room temperature, exceeded the recommended maximum level for the city’s offices in 27 of the 32 homes tested.
A researcher revealed that the situation could be aggravated by factors such as high-rise living, subdivided flats, a lack of windows and ventilation in some rooms, and restaurants occupying ground-floor premises in residential buildings.
Lai Ka Man from Baptist University led the research in March and revealed that the highest outdoor micro-particle pollution register was 94 million particles per liter (ppl), recorded at a junction in Causeway Bay, while a flat in the New Territories recorded levels a worrying 46.8 percent higher, at 138 million ppl.
Conversely, a local scholar from USJ’s Institute of Science and Environment told the Times that Macau is yet to conduct a study on indoor pollution in the territory, but believes high levels are likely to be found, particularly in smaller properties. The expert said that in Macau, the kitchen is the main source of pollutants, as hazardous levels of toxins can be released when cooking.
“There are exhaust fans, but houses here in Macau are small so such fans or chimney tubes are not efficient enough to extract pollutants, especially when frying,” the local scholar added.
Moreover, studies in other countries have also found that indoor air pollution levels can be higher than those outdoors. Staff reporter