PM2.5 levels at Sham Shui Po rose as high as 117 µg/m³ on Wednesday after a 100-metre long vessel carrying over a million kilograms of metal waste caught fire at 5:26pm (June-2).
The animation below clearly shows the progression of the toxic cloud, which moved slowly north until dissipating at around 5am on Thursday.
As reported by the SCMP1, law enforcement sources said that the fire's emissions were not toxic, according to tests carried out by firefighters. Regardless of the accuracy of this statement, the ultra high concentration of PM2.5 particulate pollution generated by the fire was clearly a health-damaging event to anyone forced to breath the heavily polluted air.
Research by HKU estimates that every 10 µg/m³ increase in PM2.5 in Hong Kong increases the risk of dying from any cancer by 22%, including an 80% increased risk of dying of breast cancer for women, and a 36% increased risk of dying of lung cancer for men2. Although these numbers reflect long term levels, acute exposure has been clearly demonstrated to increase mortality.