Burning fuels releases pollutants. Incomplete combustion produces carbon monoxide, a toxic gas that stops blood carrying oxygen, and soot (carbon particulates) that harms lungs and causes global dimming. Sulfur in fuels forms sulfur dioxide, and the high temperature in engines makes oxides of nitrogen; both cause acid rain and breathing problems. Catalytic converters and low-sulfur fuels reduce these emissions.
Humans also depend on Earth's resources for water. Potable (drinking) water is not pure; it has low levels of dissolved salts and microbes. In many countries fresh water is filtered and sterilised with chlorine, ozone or ultraviolet light. Where fresh water is scarce, sea water can be desalinated by distillation or reverse osmosis, but this needs a lot of energy. Life cycle assessments compare the environmental impact of products from raw materials to disposal.
Worked example
Why is carbon monoxide so dangerous?
- It has no colour or smell, so it is hard to detect.
- It binds to haemoglobin in red blood cells.
Answer:So the blood carries less oxygen, which can kill.
Key words
- incomplete combustion
- burning with too little oxygen
- carbon monoxide
- toxic gas from incomplete combustion
- acid rain
- rain made acidic by sulfur dioxide and nitrogen oxides
- potable water
- water that is safe to drink
New questions every time.
NGSS-referenced: HS-ESS3-4