Air in Sham Shui Po so polluted it's unsafe: green group

Residents in more than half of Sham Shui Po breathe in more pollutants than the World Health Organisation deems safe and government figures are not showing the real picture, an environmental concern group says.

The Clean Air Network based its comments on monitoring of seven roadside locations in the district over a one-month period.

It found that average daily concentrations of PM2.5 - fine airborne particles small enough to enter the lungs and blood - at four sites were higher than the WHO's recommended level of 25 micrograms per cubic metre of air each day.

Shek Kip Mei, Nam Cheong and Cheung Sha Wan recorded PM2.5 levels of 26, 28 and 35 respectively.

Yen Chow Street had an average daily PM2.5 level of 41, with 60 per cent of hourly occurrences above the WHO limit.

The highest reading recorded there in a day was 67 - four micrograms per cubic metre higher than the Environmental Protection Department's reading, the Clean Air Network said.

Four other areas also recorded average hourly concentration levels that, over 24 hours, were higher than the department's readings at its general air-quality monitoring station on Yen Chow Street, the group added.