Chinese University researchers have called on the government to broaden its air quality review objectives, after a new study found that coarse particles pose a graver health threat than earlier suspected.
The researcher behind the study called on both the World Health Organisation and local authorities to establish a monitoring system for 'coarse' respirable suspended particles (RSPs) - between 2.5 and 10 microns in diameter.
RSPs include cancer-causing particles, and many studies have looked at particles under 2.5 microns (PM2.5) across - long recognised as a significant health hazard - and those 10 microns across (PM10).
This is one of the few studies to focus on particles that fall between PM2.5 and PM10.
'The size of particles is directly linked to their potential for causing health problems,' said Professor Ignatius Yu Tak-sun, head of the division of occupational and environmental health at Chinese University. 'Unlike fine particles, which are inhaled deeply into the lung, these coarse suspended particles ... mostly stay in the upper respiratory system.'
The research, published in Environmental Health Perspectives last month, compared day-to-day variations between hospital admissions in all Hong Kong public hospitals and pollution levels observed at a Hong Kong Observatory station in Tsuen Wan - the city's only station that monitors such particles.