Pollution
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94 free Pollution trivia questions with answers — science & nature quiz, new questions added Oct 2026.
Pollution killed about nine million people in 2019, one death in six, and most of that was the air. It is also older than you think: soot on cave ceilings, Roman lead in Greenland ice, and a 1306 royal ban on burning coal in London. These 94 questions cover the science and the history: point versus nonpoint sources, PM2.5, photochemical smog, acid rain's pH, biomagnification and ocean acidification, forever chemicals and microplastics, plus the disasters that built environmental law: the Great Stink and the Great Smog, Donora, the burning Cuyahoga, Minamata, Love Canal, Bhopal, the Exxon Valdez, Lake Karachay and the Montreal Protocol. A few questions on the economics, too: externalities, Pigouvian taxes and the world's dirtiest industries. Every answer is cited to a page we checked. Play it solo, or print it for an environmental science class or Earth Day round.
30 of 94 questions with answers and explanations. Play the quiz
Q 01Pollution coming from one concentrated site, like a factory, is called what?
Point source
Agricultural runoff and microplastics are the classic nonpoint sources.
Q 02About how many deaths worldwide did pollution cause in 2019?
About 9 million
About 9 million, roughly one death in six, and rising deaths from outdoor air and chemicals offset gains against dirty water and indoor smoke.
Q 03Which conditions cause the most deaths linked to outdoor air pollution?
Heart disease and stroke
Heart disease and stroke lead the toll, since the finest particles can pass from the lungs into the bloodstream.
Q 04Before the 1860s, what did the word 'pollution' usually refer to?
Desecration of something sacred
Desecration of something sacred fits the word's Latin root polluere, 'to soil or defile', long before it meant dirtying the environment.
Q 05PFAS compounds are informally known by what nickname?
Forever chemicals
Forever chemicals barely break down in nature, so PFAS now turn up in the blood of people and animals all over the world.
Q 06The smog of car-choked cities forms when exhaust gases react with what?
Sunlight
Sunlight drives the reactions that turn car exhaust gases into ozone, the main ingredient of this kind of smog.
Q 07Particulate matter labeled PM2.5 is measured in what unit?
Micrometres
Micrometres: particles 2.5 micrometres across or smaller are fine enough to pose the greatest health risk of all the particle sizes.
Q 08Which gas can kill people at concentrations below one part per thousand?
Hydrogen sulfide
Hydrogen sulfide smells of rotten eggs at first, but it quickly deadens the sense of smell, so victims may not notice it until too late.
Q 09Which country has emitted the most carbon dioxide in total since the Industrial Revolution?
United States
The United States leads all-time emissions with about a fifth to a quarter of the total, though another country now emits more each year.
Q 10Which country became the world's largest yearly emitter of carbon dioxide in the late 2000s?
China
China took the lead in yearly emissions while still ranking far behind wealthy countries in emissions per person.
Q 11The Vietnam War defoliant Agent Orange was contaminated with which compound?
Dioxin
Dioxin, a by-product of herbicide production, is why Agent Orange exposure has been linked to cancer and birth defects.
Q 12Which heavy metal is found in rechargeable batteries and is a frequent soil contaminant?
Cadmium
Cadmium in soil is taken up by crops, which is why most people's exposure comes from food or from cigarettes.
Q 13Which carmaker admitted in 2015 to fitting diesel cars with software that cheated emissions tests?
Volkswagen
Volkswagen's software switched full emissions controls on only during tests, so on the road its cars emitted up to 40 times the US limit.
Q 21Which annual event began on April 22, 1970, with US rallies and teach-ins against pollution?
Earth Day
Earth Day drew about 20 million Americans to rallies and teach-ins, and before the year was out the EPA had been established.
Q 22Which toxic metal was phased out of car fuel worldwide in 2021, when Algeria stopped selling it?
Lead
Lead in petrol had fouled air, soil and water for almost a century, harming children's developing brains.
Q 23Which English king banned the burning of mineral coal in London in 1306?
Edward I
Edward I acted because burning sea-coal was fouling London's air.
Q 14Over which continent does the ozone hole open wide each spring?
Antarctica
Antarctica's extreme winter cold forms polar stratospheric clouds, and when daylight returns in spring, chlorine released on them destroys ozone.
Q 15What did the huge 1991 eruption of Mount Pinatubo cause worldwide for the next year or two?
Lower global temperatures
Lower global temperatures followed as its haze high in the stratosphere reflected solar energy back into space for more than a year.
Q 16What does the US Superfund program pay to clean up?
Toxic waste sites
Toxic waste sites: the 1980 law taxed chemical and petroleum companies to fund cleanups when no responsible polluter could be found.
Q 17Which bird of prey nearly vanished from the lower 48 US states after DDT thinned its eggshells?
Bald eagle
Bald eagle numbers rebounded after the US banned DDT, and in 2007 the bird came off the endangered species list.
Q 18As dissolved carbon dioxide lowers the ocean's pH, which marine life is especially at risk?
Corals and mollusks
Corals and mollusks build shells and skeletons from calcium carbonate, whose raw materials grow scarcer as seawater's pH falls.
Q 19Which two pollutants are the main causes of acid rain?
Sulfur dioxide and nitrogen oxides
Sulfur dioxide and nitrogen oxides, mostly from burning fossil fuels, react with water in the air to form sulfuric and nitric acids.
Q 20In environmental economics, pollution from manufacturing is an example of what?
A negative externality
A negative externality: because polluters don't pay the full cost of the fumes, the market produces too much of such goods.
Q 24What nickname did Londoners give the thick coal fogs that plagued London?
Pea-soupers
Pea-soupers had marked London since the 19th century, and the worst, in December 1952, disrupted travel for days.
Q 25Which tiny plastic particles did a 2015 US law ban from rinse-off cosmetics and toothpaste?
Microbeads
Microbeads scrubbed skin and teeth, but they slipped down drains and through water treatment into rivers, lakes and the sea.
Q 26Which Pennsylvania town suffered a deadly smog event in the late 1940s?
Donora
Donora's smog killed 20 people and helped push the US toward federal air pollution laws.
Q 27The Great Smog of 1952 prompted which landmark British law?
Clean Air Act of 1956
The Clean Air Act of 1956 made homes and factories in affected urban areas switch from raw coal to cleaner fuels.
Q 28What weather system trapped the Great Smog of 1952 over London?
An anticyclone
An anticyclone caused an inversion that trapped cold air and chimney smoke under warmer air for five days; about 4,000 deaths were counted at first.
Q 29Who wrote Fumifugium, an early 1661 tract against London's air pollution?
John Evelyn
John Evelyn, the diarist, addressed it to King Charles II and Parliament, proposing remedies for the city's foul air.
Q 30Which Michigan city switched to river water to save money in 2014, leaving its tap water contaminated?
Flint
Flint's river water proved so corrosive that General Motors stopped using it at its engine plant.