Take the pledge to vote

For a better tommorow#AajSawaroApnaKal
  • I agree to receive emails from News18

  • I promise to vote in this year's elections no matter what the odds are.
  • Please check above checkbox.

    SUBMIT

Thank you for
taking the pledge

Vote responsibly as each vote counts
and makes a diffrence

Disclaimer:

Issued in public interest by HDFC Life. HDFC Life Insurance Company Limited (Formerly HDFC Standard Life Insurance Company Limited) (“HDFC Life”). CIN: L65110MH2000PLC128245, IRDAI Reg. No. 101 . The name/letters "HDFC" in the name/logo of the company belongs to Housing Development Finance Corporation Limited ("HDFC Limited") and is used by HDFC Life under an agreement entered into with HDFC Limited. ARN EU/04/19/13618
LIVE TV DownloadNews18 App
News18 English
News18 » India
2-min read

Delhi Under Smog-screen: All You Need to Know About Key Pollutants

PM10 and PM2.5 simply mean particulate matter 10 micrometers or less and 2.5 micrometers or less in diameter, respectively.

Aradhna Wal | News18.com

Updated:November 9, 2017, 3:39 PM IST
facebookTwitterskypewhatsapp
Delhi Under Smog-screen: All You Need to Know About Key Pollutants
Women try to protect themselves from heavy smog and air pollution that reached hazardous levels in New Delhi. (PTI)
Loading...

New Delhi: The air quality in Delhi on Thursday noon recorded an AQI (Air Quality Index) reading of 491 — the high end of the “severe” category. As fear and concern spread like the toxic smog outside, Delhiites have become familiar with terms such as PM10 and PM2.5 to describe their day and their well-being.

PM10 and PM2.5 simply mean particulate matter 10 micrometers or less and 2.5 micrometers or less in diameter, respectively. The Australian government’s National Pollution Inventory describes it best -- a human hair is 100 micrometers in diameter. It could fit 40 fine particles of PM2.5 in its width. These micro particles have been swimming in our air, entering our lungs and wreaking havoc in Delhi, especially in winters, the past few years. But where do they come from?

The IIT Kanpur report of 2016 — Comprehensive Study on Air Pollution and Green House Gases (GHGs) in Delhi — is, so far, the most comprehensive and reliable source of answering this question. Scientists do warn that air pollution data is dynamic and what may be the biggest pollutant this year may not be the next. However, it offers a close look at Delhi's worse culprits poisoning the air.

Note: Secondary particles are formed in the atmosphere because of reaction of precursor gases (SO2, NOx, and NH3), which is seen more in winter. Secondary particles and combustion particles from biomass burning, solid waste burning, vehicle emissions, chulhas, pet coke, etc, form a large chunk of PM2.5

PM10

Road dust, the biggest contributor to PM 10 is seen to be higher in summer than in winter. In summer, says the study, soil and ash ponds are dry and the high wind speed makes particles from these sources airborne. This, apparently, is why summer looks whitish to greyish. In winter, about 40% of PM10 comes from secondary particles and combustion related carbons.

PM10

Annual Emission Load of different sources in Delhi

Road Dust: 56%

Concrete batching: 10%

Industrial stack: 10%

Vehicles: 9%

Domestic sources: 5%

PM2.5

Again, road dust and fly ash are significant contributors in summer, and secondary particles and combustion related carbons in summer

PM2.5

Annual Emission Load of different sources in Delhi --

Road Dust: 38%

Vehicles: 20%

Domestic sources: 12%

Industrial stack: 11%

Concrete batching: 6%

Since PM2.5 is the most highly concentrated pollutant during the bad winter days, a further seasonal beak down has been done.

PM 2.5 winters

Winter

Secondary Particles: 30%

Biomass burning: 26%

Vehicles: 25%

Solid Waste burning: 8%

Soil and Road Dust: 4%

Coal and Fly Ash: 5%

Construction material: 2%

PM 2.5 summers

Summer

Soil and Road Dust: 28%

Coal and Fly Ash:26%

Secondary Particles: 15%

Biomass Burning: 12%

Vehicles: 9%

Solid Waste Burning:7%

Construction Material: 3%

NOx -- mainly nitrogen dioxide (NO2) emissions in Delhi –

NO2

Itself a pollutant from industries and vehicles, NOx is doubly dangerous as it forms secondary particles, which are a large chunk of PM2.5

Annual Emission Load of different sources in Delhi -

Industrial stack: 52%

Vehicles: 36%

Diesel generator sets: 6%

Domestic sources: 3%

Aircrafts: 2%

Get the best of News18 delivered to your inbox - subscribe to News18 Daybreak. Follow News18.com on Twitter, Instagram, Facebook, TikTok and on YouTube, and stay in the know with what's happening in the world around you – in real time.

| Edited by: Ananya Chakraborty
Read full article
Loading...
Next Story
Next Story

Also Watch

facebookTwitterskypewhatsapp

Live TV

Loading...
Countdown To Elections Results
To Assembly Elections 2018 Results