SATHEE: Environmental Science

Environmental Science - Quick Revision

The Greenhouse Effect is natural & essential; Global Warming is its human-accelerated version.
BOD (Biochemical Oxygen Demand) ↑ = water pollution ↑.
E-10 fuel = 10 % ethanol + 90 % petrol; cuts CO by 20 %.
Montreal Protocol (1987) phased out CFCs to save the Ozone layer.
Keoladeo Ghana (Raj.) & Sundarbans (W.B.) are Ramsar wetlands.
Coral bleaching occurs when sea temp. rises >1 °C above summer max.
PM 2.5 particles can enter bloodstream; safe annual WHO limit = 5 µg/m³.
Noise >75 dB for 8 h causes hearing loss; >120 dB is pain threshold.
BS-VI norms cut Sulphur in diesel to 10 ppm (from 50 ppm in BS-IV).
E-waste = fastest-growing waste stream; 70 % of heavy metals in landfills come from it.
Carbon tax puts a price on CO₂ emissions; India launched $6/t in 2010.
Kyoto’s CDM lets developed nations invest in green projects in developing ones.
Chipko (1973) & Appiko (1983) were tree-hugging movements.
Project Tiger 1973 → 53 reserves; Project Elephant 1992 → 32 ranges.
3-R hierarchy: Reduce > Reuse > Recycle.

Formula/Rule	Application
DBH = diameter at breast height (1.37 m)	Standard tree biomass estimate.
Noise dose % = (C₁/T₁ + C₂/T₂ + …) × 100	Assess worker exposure limit (85 dB = 8 h).
AQI = max{sub-index of pollutants}	Daily air-quality category.
CO₂ equivalent = Σ (gas amount × GWP)	Compare greenhouse gases.
Rainwater harvest potential (kL) = Roof area (m²) × Rainfall (m) × 0.85	Urban water-saving design.
Doubling time (years) = 70 / % growth rate	Population/resource exponential growth.
10 % law (Lindeman)	Only ~10 % energy transfers to next trophic level.
C/N ratio >30	Favours fungi; <20 speeds bacterial composting.
Safe limit of ozone = 0.05 ppm (8-h avg)	Human health threshold.

“MRS GREN” = 7 life processes → Movement, Respiration, Sensitivity, Growth, Reproduction, Excretion, Nutrition.
“OIL Rigs” → Oxidation Is Loss, Reduction Is Gain (electrons) → helps redox in smog chemistry.
“Please Stop Calling Me A Silly Zebra” → Primary, Secondary, Tertiary, Quaternary consumers in food chain.
“Ramesh Can Never Cut School” → Reduce, Reuse, Recycle, Recover, Compost, Segregate (waste hierarchy).
“CFC” → Claws For Cancer (ozone hole).

Mistake	Correct Approach
Confusing Greenhouse gases with Ozone-layer depleters	GHGs warm Earth; CFCs destroy O₃—different lists.
Writing BS-VI sulphur limit as 50 ppm	Remember 10 ppm (drop the zero of 50).
Treating all wetlands as Ramsar sites	Only 75 Indian sites are officially listed; others are just wetlands.
Using BOD & COD interchangeably	BOD = bio-ox. demand (5 days, 20 °C); COD = chemical ox. demand (2 h, hot).
Calling CO a greenhouse gas	CO is indirect GHG; it forms CO₂ & O₃, not listed in IPCC basket.

Scan map: 5 Tiger reserves & 5 Ramsar sites—questions come state-wise.
Acronyms first: Write full forms (CFC, BOD, AQI, CDM) in answers—fetch ½ mark.
Units matter: dB, ppm, µg/m³—quote them, don’t leave naked numbers.
Rule of 3: For “name measures” questions, give exactly 3—neither 2 nor 4.
Eco-dates: 1972 (Stockholm), 1987 (Montreal), 1992 (Rio), 1997 (Kyoto), 2015 (Paris)—timeline in head.

1. Which pollutant is primarily responsible for the Bhopal Gas Tragedy?

**Answer:** Methyl Isocyanate (MIC)

2. The 10 % energy transfer law in an ecosystem was proposed by—

**Answer:** Lindeman

3. India’s first national park (1936) now called—

**Answer:** Jim Corbett (originally Hailey)

4. Under BS-VI, maximum sulphur in diesel is—

**Answer:** 10 ppm

5. Which is NOT a greenhouse gas? CH₄, N₂O, CO, SO₂

**Answer:** SO₂