STUDENT SPACE · TOPIC 1

Air and pollutants

Link each specified pollutant to its source and adverse effects.

The essentials

Approximately 78% nitrogen and 21% oxygen. The remaining 1% includes noble gases and carbon dioxide.
Complete combustion of carbon fuels produces CO₂. Limited oxygen can produce toxic CO and particulates.
At high engine temperatures, nitrogen reacts with oxygen to form nitrogen oxides. They contribute to acid rain, smog and respiratory problems.

Try each question before opening its hint or answer. Use paper for calculations and diagrams.

Why can a nitrogen-free fuel still lead to nitrogen oxides in an engine?

Need a hint for Question 1?

Identify whether the source is fuel, air or biological decay. Distinguish complete from incomplete combustion.

Check Question 1

Nitrogen and oxygen from the air react at the high engine temperature.

State the approximate nitrogen and oxygen percentages in clean dry air.

Need a hint for Question 2?

Most dry air is nitrogen, with oxygen next.

Check Question 2

Nitrogen 78%; oxygen 21%.

Name the pollutant responsible for each: toxic gas from incomplete combustion; acid rain from sulfur-containing fuel.

Need a hint for Question 3?

Distinguish carbon-containing fuel from sulfur impurities.

Check Question 3

Carbon monoxide; sulfur dioxide.

Use Lesson 1 in your worksheet for written practice. Your teacher will discuss those answers in class.