Hydroxymethanesulphonate (HMS)

Context

Scientists have found aerosol particles that exist in a supercooled state during very cold winters allow the formation of hydroxymethanesulphonate

About Hydroxymethanesulphonate (HMS)

• Formation of HMS:
  • Secondary aerosol formed by the reaction of sulphur dioxide (SO₂) with formaldehyde (CH₂O) in the presence of liquid water.
  • Previously believed to form only under warm conditions; now found to form under extremely cold conditions as well.
• HMS as a Secondary Aerosol:
  • Classified as a secondary aerosol because it forms in the atmosphere through chemical reactions involving primary pollutants like SO₂.
• Impact on PM2.5:
  • Increases the acidity of particulate matter (PM2.5).
  • Promotes the formation of other secondary aerosols, exacerbating air pollution and impacting air quality.
• Applications of Hydroxymethanesulphonate
  • Environmental Science:
    • Significant intermediate in the formation of atmospheric aerosols, especially during haze events.Aids in understanding aerosol properties and formation.
  • Air Quality Monitoring:
    • Acts as a marker for specific pollutants, enabling air quality assessments.
  • Industrial Applications:
    • Potential precursor in chemical reactions and synthesis.Used as a sulfonating agent for introducing sulfonic acid groups into molecules.
  • Water Treatment:
    • Potential application in pollutant removal and controlling water chemistry.
  • Biochemistry:
    • Utilized in enzyme kinetics research and other biological studies.

Particulate Matter Pollution

• A complex mixture of small particles and liquid droplets suspended in the air.
• Types of Particulate Matter:
  • PM10 (Coarse Particles): Diameter ≤ 10 micrometres.
  • PM2.5 (Fine Particles): Diameter ≤ 2.5 micrometres.
• Sources:
  • Emitted from construction activities, unpaved roads, agricultural fields, and fires.
• Health Impacts of PM Pollution:
  • PM10: Causes irregular heartbeats, aggravated asthma, and reduced lung function.
  • PM2.5: Increases risk of heart attacks, strokes, and other cardiovascular diseases.
• Climate and Natural Cycles:
  • Alters atmospheric processes, affecting climate patterns and natural cycles like the water cycle.

Source: TH

---

Previous Year Question

In the cities of our country, which among the following atmospheric gases are normally considered in calculating the value of Air Quality Index?
1. Carbon dioxide
2. Carbon monoxide
3. Nitrogen dioxide
4. Sulfur dioxide
5. Methane

Select the correct answer using the code given below:

[UPSC Civil Services Exam – 2016 Prelims]

(a) 1, 2 and 3 only
(b) 2, 3 and 4 only
(c) 1, 4 and 5 only
(d) 1, 2, 3, 4 and 5

Answer: (b)

---