Air Pollution and Health Effects

Air Pollution and Health Effects - Pollutant Parade

• Primary Pollutants: Emitted directly from a source.
  • Particulate Matter (PM): PM${2.5}$ (≤2.5 µm), PM${10}$ (≤10 µm). Sources: Combustion (vehicles, industry), dust. Effects: Respiratory (asthma, bronchitis), cardiovascular diseases.
  • $SO_2$ (Sulphur Dioxide): Burning fossil fuels (coal, oil). Effects: Bronchoconstriction, acid rain precursor.
  • $NO_x$ (Nitrogen Oxides): Vehicle exhaust, power plants. Effects: Lung irritation, smog & acid rain component.
  • $CO$ (Carbon Monoxide): Incomplete combustion. Effects: Hypoxia; carboxyhemoglobin (affinity for Hb 200-250x > $O_2$).
  • Lead (Pb): Smelters, battery manufacturing, old paint. Effects: Neurotoxic, nephrotoxic, hematotoxic.
• Secondary Pollutants: Formed in atmosphere by chemical reactions.
  • $O_3$ (Ozone): Formed from $NO_x$ + VOCs + Sunlight. Effects: Respiratory tract irritation, ↓ lung function.
  • Photochemical Smog: Includes $O_3$, PAN (Peroxyacetyl Nitrate).

⭐ Bhopal Gas Tragedy (1984) involved Methyl Isocyanate (MIC), a highly toxic primary pollutant, causing immediate mass casualties and long-term health issues.

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Air Pollution and Health Effects - System Under Siege

Air pollutants act as systemic stressors, impacting multiple organ systems. Fine particulate matter ($PM_{2.5}$) is a key culprit.

• Key Pollutants & Systemic Effects:

  • $PM_{2.5}$/$PM_{10}$: Deep lung penetration; Respiratory (asthma, COPD, cancer), Cardiovascular (IHD, stroke).
  • $SO_2$: Bronchoconstriction; exacerbates asthma.
  • $NO_x$: Lung irritation, inflammation; ↑respiratory infections.
  • $CO$: Systemic hypoxia (carboxyhemoglobin); 📌 $CO$ affinity for Hb >200x $O_2$.
  • $O_3$ (ground-level): Lung inflammation, ↓lung function; asthma trigger.
  • Lead (Pb): Neurotoxic (children esp.); hematologic, renal effects.

• High-Risk Populations:

  • Children: Impaired lung development, ↑infections.
  • Elderly: Worsening of chronic conditions.
  • Pregnant women: Low birth weight, preterm birth.
  • Cardio-respiratory patients: Acute exacerbations.

⭐ $PM_{2.5}$ exposure is a leading environmental risk factor for global disease burden, significantly contributing to NCDs like IHD and stroke.

Air Pollution and Health Effects - India's Air Watch

• NAAQS (National Ambient Air Quality Standards):
  • Monitors 12 key pollutants (e.g., PM10, PM2.5, NO2, SO2, CO, O3, NH3, Pb, Benzene, BaP, As, Ni).
  • Established by CPCB (Central Pollution Control Board).
• AQI (Air Quality Index): "One Number - One Colour - One Description".
  • Calculated for 8 major pollutants (PM10, PM2.5, NO2, SO2, CO, O3, NH3, Pb).
  • Six categories: Good (0-50), Satisfactory (51-100), Moderate (101-200), Poor (201-300), Very Poor (301-400), Severe (>400).

  ⭐ The AQI transforms complex air quality data into a single, understandable number, aiding public awareness and health advisories.

Air Pollution and Health Effects - Clearing The Smog

• Control Approaches (Hierarchy):

  • Elimination/Substitution: Phase out polluters (e.g., leaded petrol); promote cleaner fuels (CNG, EVs).
  • Engineering Controls: Modify processes/equipment (industrial scrubbers, catalytic converters, taller stacks).
  • Administrative Controls: Legal measures, zoning, emission standards, NAQI, public awareness.
    • Green belts: Act as pollution barriers; ideally 500m-1km wide.
  • Personal Protective Equipment (PPE): N95/FFP2 masks during smog (least effective at population level).

• Key Indian Legislative Framework:

  • Air (Prevention and Control of Pollution) Act, 1981: Primary legislation.
  • Environment (Protection) Act, 1986: Umbrella act for environmental regulation.
  • National Clean Air Programme (NCAP): Targets PM reduction.

⭐ The National Air Quality Index (NAQI) monitors 8 major pollutants (PM10, PM2.5, NO₂, SO₂, CO, O₃, NH₃, Pb) across 6 color-coded categories.

High‑Yield Points - ⚡ Biggest Takeaways

• CO: Forms Carboxyhemoglobin (Hb affinity ~210x > O2), causing tissue hypoxia.
• PM2.5: Most dangerous particulate; causes cardiovascular/respiratory diseases, lung cancer.
• SO2: Induces bronchoconstriction (asthma exacerbation); NOx: Respiratory irritation.
• Pneumoconioses: Silicosis (silica), Asbestosis (asbestos; mesothelioma risk), Byssinosis (cotton dust).
• Ground-level Ozone (O3): Potent respiratory irritant, causes lung cell damage.
• National Air Quality Index (AQI) monitors 8 key pollutants including PM2.5, SO2, O3, CO.
• Air (Prevention and Control of Pollution) Act, 1981: Key Indian environmental legislation.