Domestic Wastewater & Pollutants at Home
Teacher Guiding Questions (Classroom Inquiry):
"What pollutants enter the drain when we wash dishes or shower? Where does this dirty water end up if it isn't treated properly?"
Dishwashing Grease & Detergents
Oils, leftover food bits, and chemical detergents flow down drains, creating giant fatbergs in sewers and cutting oxygen in aquatic ecosystems.
Shower Soap & Chemical Shampoos
Phosphates and synthetic surfactants from body wash and shampoo alter river pH and cause toxic algal blooms.
Microfibres from Synthetic Clothes
Every wash cycles releases millions of invisible microscopic plastic synthetic threads directly into the ocean.
How Water Pollution Affects Humans, Animals & Plants
WHO Fact Link (p.23 textbook sidebar):
"According to the World Health Organization (WHO), over 1.7 billion people globally drink water contaminated with faeces, transmitting cholera, dysentery, and typhoid."
Sewage Discharged into Rivers & Ponds
Pond water turns green or black; rotting organic waste strips dissolved oxygen, killing fish and freshwater organisms.
Seabirds & Marine Life Covered in Oil
Oil destroys the waterproof insulation of bird feathers, causing hypothermia, inability to fly or hunt, and death.
Solid Rubbish & Trash Blocking Rivers
Floating plastic bags and containers clog natural drainage waterways, creating foul odours and flash floods during storms.
Eating Polluted Seafood (Human Health)
Microplastics and heavy metals bioaccumulate in fish and shellfish, returning directly into the human food chain.
What Causes Air Pollution? (Sources & Human Habits)
Indoors Sources (Textbook p. 24)
① Second-hand Cigarette Smoke
Carcinogens, carbon monoxide, and particulate matter linger indoors, damaging children's lung alveoli.
② Painting Walls & Volatile Organic Compounds (VOCs)
Fresh oil-based paint, varnishes, and renovation solvents release pungent toxic chemicals into indoor air.
③ Cooking Fumes without Proper Ventilation
High-heat oil frying produces concentrated PM2.5 aerosols that irritate breathing airways without an exhaust fan.
Urban Area & Countryside Sources (Textbook pp. 24–25)
④ Vehicle & Cargo Ship Exhaust
Diesel engines from container ships and roadside traffic emit nitrogen oxides (NOx) and fine black soot.
⑤ Industrial Factory Smoke
Coal combustion and industrial boilers blast sulfur dioxide and heavy particulate smog over metropolitan areas.
⑥ Countryside Hill Fires (Wildfires)
Careless hikers leaving burning embers trigger hill fires, destroying flora and producing thick smoke columns.
Which Methods Can Reduce Air Pollution? Put a ✓ in the ◯
Click on each behaviour card to test whether it helps reduce air pollution or worsens it.
Put out the barbecue fire before leaving
Prevents accidental spark ignition and catastrophic countryside hill fires.
Take a taxi frequently
Increases roadside vehicle trips and tailpipe emissions per passenger.
Take public transport (e.g. MTR / electric buses)
High capacity mass transit reduces private vehicles on roads.
Advise family members not to smoke
Stops toxic tobacco burning particles inside homes and public areas.
Walk instead of taking a vehicle for short distances
Zero emissions produced, promotes physical cardiovascular fitness.
Overuse chemical pesticides
Aerosol chemicals evaporate into the breeze, poisoning helpful insects.
Effects of Air Pollution on Humans, Animals & Plants
Roadside Plants Coating
Exhaust soot and dust coat green leaves, blocking sunlight stomata and stopping photosynthesis.
Bees Losing Scent Trail
Chemical oxidants degrade flower scent molecules; pollinators cannot locate flowers to pollinate crops.
Human Lung & Asthma Illness
Breathing PM2.5 leads to chronic bronchitis, triggering severe asthma attacks and cardiovascular strain.
Low Visibility & Traffic Hazards
Dense particulate haze obscures roads and harbour channels, causing vehicle collisions and maritime delays.
Air Quality Health Index (AQHI) Interactive Simulator
Air quality is satisfactory. No health precautions needed. Normal outdoor activities for students and teachers can proceed.
How Plastic Causes Both Air and Water Pollution
When Making Plastic Bottles... (Air Pollution)
Petroleum refining, chemical cracking, and plastic bottle moulding release greenhouse gases and volatile toxic air pollutants into the atmosphere.
Dumping Plastic Waste into Seas... (Water Pollution)
Discarded single-use bottles and shopping bags float into oceans, entangling marine turtles and slowly breaking down into microplastics.