BIOTIC COMPONENTS (Living):
- Producers: Plants (create food from sunlight)
- Primary Consumers: Herbivores (eat plants)
- Secondary Consumers: Carnivores (eat herbivores)
- Decomposers: Bacteria, fungi (break down dead matter)

ABIOTIC COMPONENTS (Non-living):
- Sunlight (energy source)
- Temperature (affects organism distribution)
- Water (essential for all life)
- Soil (nutrients and support)
- Atmosphere (oxygen, CO₂)

FOOD CHAIN Example:
Plant → Grasshopper → Frog → Snake → Eagle

ENERGY LOSS:
- Each level loses 90% energy as heat
- Producer: 100% energy
- Primary consumer: 10% of producer energy
- Secondary consumer: 1% of producer energy
- This is why food chains have 4-5 levels max

TROPHIC LEVELS:
- Level 1 (Producers): Plants
- Level 2 (Primary): Herbivores
- Level 3 (Secondary): Small carnivores
- Level 4 (Tertiary): Large carnivores

BIODIVERSITY = Variety of life at all levels

GENETIC DIVERSITY
- Variation within species
- Enables adaptation
- Example: Different dog breeds from same species

SPECIES DIVERSITY
- Number of different species
- Amazon rainforest: 10% of world's species
- More diversity = safer ecosystems

ECOSYSTEM DIVERSITY
- Different habitat types
- Forests, grasslands, deserts, oceans
- Each has unique species

IMPORTANCE:
✓ Food security (crop varieties)
✓ Medical discoveries
✓ Ecosystem stability
✓ Aesthetic value

PRIMARY POLLUTANTS (Directly emitted)
- CO (Carbon monoxide): Incomplete fuel combustion
- NO₂ (Nitrogen dioxide): Power plants, vehicles
- SO₂ (Sulfur dioxide): Coal burning
- PM (Particulate matter): Dust, smoke
- VOCs (Volatile organic compounds): Paint, solvents

SECONDARY POLLUTANTS (Formed in atmosphere)
- Ozone (O₃): From reaction of NOx + sunlight
- PAN (Peroxyacyl nitrate): From vehicle exhaust
- Smog: Mixture of pollutants (photochemical)

ANTHROPOGENIC (Human-caused) - 70%:
- Transportation (40%): Cars, buses, trucks
- Industry (20%): Manufacturing, power plants
- Residences (10%): Cooking, heating
- Agriculture: Fertilizers, burning

NATURAL SOURCES (30%):
- Volcanic eruptions (ash, SO₂)
- Forest fires (smoke, particles)
- Soil dust (wind erosion)
- Sea salt spray
- Biogenic emissions (plants)

ON HEALTH:
- Respiratory diseases: Asthma, bronchitis
- Cardiovascular problems: Heart attacks
- Eye irritation: Smog exposure
- Cognitive effects: Reduced learning
- Premature death: 7 million/year globally

ON ENVIRONMENT:
- Acid rain: pH < 5.6
- Ozone layer depletion: Skin cancer increase
- Global warming: CO₂ and CH₄ trap heat
- Eutrophication: Nutrient overload in water

ON MATERIALS:
- Corrosion of metals
- Deterioration of building facades
- Fading of paints and dyes

SOUND MEASUREMENT:
- Decibel (dB): Logarithmic scale
- 0 dB: Threshold of hearing
- 60 dB: Normal conversation
- 85 dB: Start of hearing damage
- 140 dB: Threshold of pain
- 200+ dB: Causes immediate rupture

EXAMPLES OF SOUND LEVELS:
- Whisper: 30 dB
- Alarm clock: 80 dB
- Chainsaw: 100 dB
- Jet engine: 140 dB

SOURCES:
- Traffic (vehicles, trains, planes)
- Industrial noise (machinery)
- Construction (drilling, hammering)
- Entertainment (music, speakers)
- Domestic (appliances, power tools)

HEALTH EFFECTS OF NOISE:
- Hearing loss (most common)
- Sleep disturbance
- Stress and anxiety
- Cardiovascular effects
- Reduced cognitive function
- Tinnitus (ringing in ears)

MICROBIAL CONTAMINANTS:
- Bacteria: E. coli (causes diarrhea)
- Viruses: Hepatitis A, polio
- Parasites: Malaria, cholera
- Affect: 2 billion people (no clean water)

CHEMICAL CONTAMINANTS:
- Heavy metals: Mercury, lead, arsenic
- Pesticides: DDT (bioaccumulates)
- Industrial: PCBs, dioxins
- Pharmaceuticals: Birth control, antibiotics

NUTRIENT POLLUTION:
- Excess nitrogen and phosphorus
- From fertilizers, sewage
- Causes eutrophication (algal blooms)
- Results in dead zones (no oxygen)

PHYSICAL CONTAMINANTS:
- Sediment (turbidity)
- Plastic (microplastics in fish)
- Thermal pollution (hot water)
- Radioactive materials

POINT SOURCES (Specific location):
- Factories and mills
- Wastewater treatment plants
- Oil spills
- Mining operations
- Refineries
→ Easier to monitor and control

NON-POINT SOURCES (Diffuse, multiple locations):
- Agricultural runoff
- Urban storm water
- Atmospheric deposition
- Traffic pollution
→ Harder to trace and control

MAJOR CONTAMINANTS:
- Heavy metals: Cadmium, chromium, mercury
- Organic compounds: PCBs, PAHs, dioxins
- Pesticides: Persist for years in soil
- Radioactive materials: From nuclear accidents
- Poor waste disposal: Landfill leachate

SOIL EROSION:
- Loss of topsoil by wind and water
- Caused by deforestation, overgrazing
- Reduces fertility (less nutrients)
- Leads to desertification
- Affects crop production

EFFECTS:
- Reduced agricultural productivity
- Groundwater contamination
- Bioaccumulation in food chain
- Health impacts (cancer, neurological)
- Ecosystem damage

✓ Emission standards for vehicles and industries
✓ Shift to renewable energy (solar, wind)
✓ Improved fuel efficiency
✓ Public transportation expansion
✓ Carbon pricing and cap-and-trade systems
✓ Air quality monitoring networks
✓ Green building standards

✓ Wastewater treatment plants
✓ Industrial waste regulations
✓ Agricultural best practices (reduce runoff)
✓ Wetland restoration (natural filters)
✓ Plastic reduction initiatives
✓ Safe drinking water standards
✓ Cleanup of contaminated sites

✓ Remediation technologies
✓ Proper waste disposal systems
✓ Sustainable agricultural practices
✓ Reforestation initiatives
✓ Contaminant testing and monitoring
✓ Certification for contaminated lands

• Reduce energy consumption
• Choose public transportation
• Reduce, reuse, recycle
• Eat less meat (livestock impacts)
• Support renewable energy
• Reduce plastic use
• Buy eco-friendly products
• Garden organically
• Conserve water
• Support environmental policies

• Clean technology adoption
• Pollution prevention
• Waste minimization
• Energy efficiency
• Renewable energy use
• Circular economy (reuse materials)
• Corporate environmental responsibility
• ISO 14001 certification

- Caused by greenhouse gases (CO₂, CH₄, N₂O)
- Effects: Rising temperatures, extreme weather, sea level rise
- Solutions: Carbon neutrality, renewable energy, reforestation

- Caused by CFCs and halons
- Effect: UV radiation increase → skin cancer
- Montreal Protocol: Most successful environmental treaty
- Ozone layer recovering slowly

- Species extinction rate: 1,000x natural rate
- Causes: Habitat loss, pollution, climate change
- Conservation efforts: Protected areas, breeding programs

ENVIRONMENTAL ENGINEER
- Salary: $60,000 - $110,000
- Design pollution control systems
- Plan waste management

ENVIRONMENTAL SCIENTIST
- Salary: $55,000 - $95,000
- Research environmental issues
- Monitor ecosystems

GREEN BUILDING SPECIALIST
- Salary: $65,000 - $120,000
- Design sustainable buildings
- Certifications: LEED

CONSERVATION OFFICER
- Salary: $35,000 - $65,000
- Protect natural resources
- Manage protected areas

1. What is the role of decomposers in an ecosystem?
2. Explain the energy loss at each trophic level.
3. What is the difference between point and non-point pollution sources?
4. How do CFCs affect the ozone layer?
5. What is eutrophication and what causes it?
6. List three primary air pollutants and their sources.
7. Define bioaccumulation and give an example.
8. What are the health effects of chronic noise exposure?
9. How can individuals reduce their environmental footprint?
10. What is the role of sustainable development?