Small, yet potentially deadly – PM2.5 is one of the reasons why the haze-filled air around you appears murkier and more acrid-smelling than the Pollution Standards Index (PSI) number suggests. The PSI is an indicator of the level of major air pollutants, including PM10 – a class of particles which includes the PM2.5. Unlike the United States, which uses the Air Quality Index (AQI) – an aggregation of the levels of PM2.5, ozone and other major air pollutants – Singapore’s National Environment Agency (NEA) has both the PSI and PM2.5 indicators on its site.
Studies conducted by Beijing University in China have directly linked PM2.5 to aggravated asthma conditions, lung problems and heart attacks. PM2.5 is so deadly because it is small enough to be inhaled into the bloodstream and the deepest regions of our lungs. Coarser PM10 particles, on the other hand, are normally more benign because they are usually trapped by the nasal passages or pass directly through the body.
So snap on the N95 mask when the PM2.5 reading exceeds 40, says an expert from the Singapore Environment Council. It’s an indication of unhealthy PM2.5 levels in the air. The 24-hour PM2.5 Concentration (µg/m3) in Singapore crept pass the 200 mark on Jun 20, 2013. The World Health Organisation (WHO) appears to be more conservative – recommending no more than 25 micrograms of PM2.5 in the air over a 24-hour average (25 μg/m3 24-hour mean).
According to experts, the N95 mask incorporates a filter system which effectively blocks out PM2.5. Still, if you have existing respiratory, cardiovascular or other related health issues, you’d want to heed the NEA’s guidelines of minimising your outdoor activities whenever the PM2.5 and PSI levels spike. And to counter the damage the haze is causing to your body, start making these changes to your diet today.