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How to gauge the effectiveness of an air purifier

Published on Mar 13, 2014 8:42 AM
Customers looking at the various models of air purifiers at Courts in Toa Payoh. -- ST FILE PHOTO: DESMOND WEE 

Air purifiers and masks are being snapped up as Singapore's air quality worsens.

But how useful are these products in filtering out pollutants, especially the tiny and hazardous PM2.5 particles?

Some, such as N95 masks and certain models of air purifiers, can be effective depending on how successfully they can remove the smaller microscopic particles.

The N95 mask, for instance, is "at least 95 per cent efficient against fine particles that are about 0.1 to 0.3 microns" in size, according to the Health Ministry's website. It added that the N95 mask is 99.5 per cent efficient against particles such as those 0.75 microns or larger.

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