Biodegradable vs Non-Biodegradable Waste, and Air Pollution

What you do

• Ask of each waste: could a microorganism eat this? That single question decides the first two bins.
• Name the four man-made sources of air pollution: vehicles, industries, burning garbage and brick kilns.

Challenges to clear

• Sort all sixteen.
• Fill the particulate bin correctly.
• Fill the Gaseous air pollutant box — pollution you cannot see.

The task

Four categories, one item at a time. Sort the wastes by whether microorganisms can break them down, and sort the air pollutants by whether they are gases or particles.

What this lesson covers

• Biodegradable waste — Microorganisms break it down into harmless, non-toxic substances: Vegetable and fruit peelings (Kitchen leftovers rot down under microorganisms, which is why this is exactly the waste used for composting into manure.); Cattle dung (Animal waste is broken down completely by microorganisms, and is the raw material for biogas as well as for manure.); Fallen leaves (Agricultural and plant waste decays into non-toxic substances, returning nutrients to the soil rather than accumulating in it.); Paper packaging (Paper is plant fibre, so microorganisms can digest it. It is the standard textbook example of a biodegradable waste alongside vegetable peels.)
• Non-biodegradable waste — Microorganisms cannot break it down at all: Polythene carry bags (Plastic may take hundreds of years to break down. Discarded polythene chokes landfills, drains and rivers, and from there is swallowed by marine animals.); Styrofoam (No microorganism can digest it. Styrofoam packing material is doubly harmful, because it also releases the CFCs that destroy the ozone layer.); Glass bottles (Glass never rots, but unlike plastic it is easily recycled — recycling of plastic, metal and glass is a listed control measure.); Electronic waste (E-waste accumulates unchanged and leaches poisonous substances into soil and water when it is dumped.)
• Gaseous air pollutant — A harmful gas given out from a source: Carbon dioxide (One of the three main gaseous pollutants in vehicle exhaust and factory emissions, and also the chief greenhouse gas.); Sulphur dioxide (A gas from both exhausts and factories. It damages the air passages in the lungs, causing bronchitis, and it dissolves in rain drops to make acid rain.); Carbon monoxide (The third of the main vehicular gaseous pollutants, alongside carbon dioxide and sulphur dioxide.); Oxides of nitrogen (Chiefly an industrial gaseous pollutant. Like sulphur dioxide it dissolves in rain to acidify it, which is why the Euro Bharat norms target sulphur and nitrogen oxides together.)
• Particulate air pollutant — Solid particles carried in the air: Rubber worn off vehicle tyres (Tyres wear away as they run and shed rubber particles into the air — a pollutant produced by the vehicle without any burning at all.); Road dust raised by speeding vehicles (Particulate pollution needs no chemistry, only disturbance. The same dust rises when road cleaners sweep in the morning.); Ash from brick kilns (A kiln leaves huge quantities of ash and broken brick bits, along with the smoke and heat it gives out.); Smoke from factory chimneys (Chimney smoke carries a great deal of particulate matter. Tall chimneys fitted with filters and electrostatic precipitators are the standard control.)

Hint

Biodegradable does not mean harmless. Untreated heaps of it breed flies, rats and insects that spread disease, and the rain run-off contaminates the surroundings. Smog is a trap too — smoke plus fog is particulate and gaseous at once.