NEWS

Lucknow, Nov 7, 2016 : The blanket of toxic air over Delhi — the product of road and construction dust, vehicle emissions, crop- and waste-burning, smoke from Diwali fireworks, and the currently prevalent cool, still atmospheric conditions – doesn’t seem to be lifting. While the government struggles to get moving on an effective long-term plan to tackle the problem, many residents have begun to invest in air-purifiers for their homes and cars. Here’s what to look for while buying one. All modern air-purifiers feature High Efficiency Particulate Arrestance (HEPA) filters. These filters are generally rated to trap particles as small as 0.3 microns – for perspective, the thickness of a strand of human hair is about 50-150 microns. Therefore, any air purifier with a HEPA filter should be able to block out both PM 2.5 (particles that are 2.5-10 microns in diameter) and PM 10 (10 microns or more in diameter) particulates.

Read More at :  http://indianexpress.com/article/explained/delhi-pollution-air-purifiers-smog-hepa-filters-3740696/