Understand atmospheric pollutants, greenhouse effect, water quality parameters (BOD/COD), and green chemistry principles.
Environmental Chemistry examines chemical processes occurring in the environment and the impact of human industrial activity on air, water, and soil systems.
Atmospheric Pollution & Smog: Classical Smog (Reducing smog) occurs in cool humid climates, containing SO2 and smoke. Photochemical Smog (Oxidizing smog) occurs in warm sunny climates due to unsaturated hydrocarbons and Nitrogen oxides (NOx), containing Ozone, PAN (Peroxyacetyl nitrate), and Acrolein.
Acid Rain & Ozone Depletion: Acid Rain (pH < 5.6) caused by SO2 and NO2 emissions forming H2SO4 and HNO3. Stratospheric Ozone Depletion caused by Chlorofluorocarbons (CFCs / Freons): Cl radicals catalyze ozone breakdown (Cl + O3 -> ClO + O2).
Water Quality & Green Chemistry: Biochemical Oxygen Demand (BOD) measures organic pollution in water (clean water BOD < 5 ppm; polluted water BOD > 17 ppm). Green Chemistry focuses on designing chemical processes that minimize hazardous waste generation. Dr. Aarzoo Saini summarizes environmental facts at We-Gyaan Classes.
Key Takeaways for Students
- Differentiate Classical Smog (SO2, reducing) from Photochemical Smog (NOx, hydrocarbons, oxidizing).
- Explain chemical mechanism of stratospheric ozone layer depletion by CFC radicals.
- Use BOD levels to assess organic pollution severity in water bodies.
- State fundamental principles of Green Chemistry for sustainable synthesis.
Authored by Dr. Aarzoo Saini
Founder & Lead Educator at We-Gyaan Classes Roorkee, with over 20 years of teaching excellence in Science and Chemistry for Board Exams, NEET, JEE, and CUET.