---
title: "Pollutants from Burning Fuels"
description: "Burning a fuel gives out more than carbon dioxide and water. Incomplete combustion produces carbon monoxide and soot, and sulfur and nitrogen end up as acidic or irritant gases."
canonical: https://lightmysky.com/learn/science/pollutants-from-burning-fuels-mt_DDiyDBy6YW
source: https://lightmysky.com/learn/science/pollutants-from-burning-fuels-mt_DDiyDBy6YW.md
retrieved: 2026-09-12
---

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# Pollutants from Burning Fuels

Burning a fuel gives out more than carbon dioxide and water. Incomplete combustion produces carbon monoxide and soot, and sulfur and nitrogen end up as acidic or irritant gases.

Subject: Science · Area: Matter & Materials · Ages 15 to 16
Page: https://lightmysky.com/learn/science/pollutants-from-burning-fuels-mt_DDiyDBy6YW

## Ready when they can

- Names the products of complete and incomplete combustion and states the harm each one does
- Explains where sulfur dioxide comes from and how it ends up as acid rain
- Explains why nitrogen oxides form in an engine when nitrogen is normally unreactive
- Evaluates one measure that cuts a named pollutant and says what it costs

## Lesson: What else comes out of the flame

Complete combustion in plenty of oxygen gives carbon dioxide and water. Starve the flame of oxygen and you get incomplete combustion instead: carbon monoxide and soot, plus unburned fuel. Carbon monoxide is a colourless killer that hijacks the blood, so a faulty heater is dangerous even when its flame looks fine.

Fuels often hold sulfur impurities, and burning turns them into sulfur dioxide. That gas dissolves into rain, which then falls acidic on forests and lakes. Stonework crumbles, fish vanish and soils sour. This acid rain can travel far past the chimney that caused it.

Engines make nitrogen oxides, even though nitrogen is normally unreactive. The extreme heat inside fuses nitrogen and oxygen from the air together. Those oxides feed smog that stings eyes and chests, and they add to acid rain. Still weather makes it all worse near roads.

**Tip.** Each pollutant has a countermeasure with a cost. Catalytic converters tame exhaust gases, scrubbers strip sulfur at power plants, and low sulfur fuels help too. All of them cost money and energy to build and run. Cutting pollution always has a bill attached.

**Recap.** Short oxygen makes CO and soot, sulfur and engine heat make acid gases, and cleanup always costs.

## Practice

8 questions on this page, each with its working shown.

## Needs first

- [Crude Oil, Fractional Distillation and Cracking](https://lightmysky.com/learn/science/crude-oil-fractional-distillation-and-cracking-mt_Jg3O4EQ9Vz)
- [Earth's Atmosphere & CO2](https://lightmysky.com/learn/science/earths-atmosphere-and-co2-mt_mTpV-0rtkO)

## Opens up

- [Rates of Reaction: Collision Theory and What Changes a Rate](https://lightmysky.com/learn/science/rates-of-reaction-collision-theory-and-what-changes-a-rate-mt_Ma2bOotr9g)