Description

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Context:

In winter, the temperature in Dras in Ladakh drops to -20º C, making it the coldest place in India.

About Particulate Matter:

Particulate pollution, also called "particulate matter" (PM), is a mixture of solid particles and liquid droplets suspended in the air. PM can be divided into two broad categories:

PM10-2.5 and PM2.5. PM10-2.5 refers to particles that are between 2.5 and 10 micrometers (µm, equal to one-millionth of a meter) in diameter, and PM2.5 refers to particles that are less than 2.5 µm in diameter.

Key Findings:

Formation of Hydroxymethanesulfonate	Hydroxymethanesulfonate is formed when formaldehyde reacts with sulfur dioxide in the presence of liquid water. Previously thought to occur only in clouds and fog, it has been observed in aerosol particles during Fairbanks winters.
Role of Temperature	Extremely low temperatures (around -35ºC) cause supercooling of aerosol particles, where liquid water remains unfrozen, enabling the formation of hydroxymethanesulfonate.
Aerosol Acidity Dynamics	Sulfate ions (SO₄²⁻): Increase acidity. Ammonium ions (NH₄⁺): Neutralize acidity.
Impact of Post-2022 Sulfur Fuel Ban	Sulfate ion concentrations decreased. Ammonium ion levels increased, reducing aerosol acidity.
Ammonium Dynamics in Cold Weather	At cold temperatures, ammonium ions are less likely to volatilize to ammonia gas. This accumulation reduces acidity further, creating favorable conditions for the formation of hydroxymethanesulfonate.

READ ABOUT

AEROSOL

PM2.5 Pollution

Cloud Seeding

Delhi's AQI Hits Severe+ Levels: GRAP and Winter Pollution

Source:

THE HINDU

PRACTICE QUESTION

Q.Discuss the impact of extremely low temperatures on aerosol particles leading to their supercooling. How does this phenomenon influence atmospheric processes and climate patterns? (150 words)