Maintaining air quality
Study G3 Science Chemistry air composition, pollutant sources and acid rain, then connect the carbon cycle and greenhouse gases to global warming.
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Before you begin
Study G3 Science Chemistry air composition, pollutant sources and acid rain, then connect the carbon cycle and greenhouse gases to global warming.
Learning goals
- Describe the composition of dry air by volume: about 78% nitrogen, 21% oxygen and the rest noble gases, mainly argon, and carbon dioxide
- Name common air pollutants, such as carbon monoxide, methane, nitrogen oxides, ozone, sulfur dioxide and unburned hydrocarbons
- State that carbon monoxide comes from incomplete combustion of carbon-containing substances
- State that nitrogen oxides come from lightning and internal combustion engines
- State that sulfur dioxide comes from volcanoes and burning fossil fuels
- Discuss why carbon monoxide is toxic
- Discuss how nitrogen dioxide and sulfur dioxide form acid rain and its effects on breathing and buildings
- Describe how combustion, respiration and photosynthesis move carbon in the carbon cycle
- Describe how the carbon cycle regulates the amount of carbon dioxide in the atmosphere
- State that carbon dioxide and methane are greenhouse gases, give their sources, and describe the possible effects of rising levels, such as extreme weather and melting polar ice
Syllabus statements covered
- describe the volume composition of gases present in dry air as being approximately 78% nitrogen, 21% oxygen and the remainder being noble gases (with argon as the main constituent) and carbon dioxide
- name some common atmospheric pollutants, e.g. carbon monoxide; methane; nitrogen oxides (NO and NO2); ozone; sulfur dioxide; unburned hydrocarbons
- state the sources of these pollutants as — carbon monoxide from incomplete combustion of carbon-containing substances
- state the sources of these pollutants as — nitrogen oxides from lightning activity and internal combustion engines
- state the sources of these pollutants as — sulfur dioxide from volcanoes and combustion of fossil fuels
- discuss some of the effects of these pollutants on health and on the environment — the toxic nature of carbon monoxide
- discuss some of the effects of these pollutants on health and on the environment — the role of nitrogen dioxide and sulfur dioxide in the formation of ‘acid rain’ and its effects on respiration and buildings
- describe the carbon cycle in simple terms, to include — the processes of combustion, respiration and photosynthesis
- describe the carbon cycle in simple terms, to include — how the carbon cycle regulates the amount of carbon dioxide in the atmosphere (see also 11.1(d))
- state that carbon dioxide and methane are greenhouse gases and may contribute to global warming; give the sources of these gases and describe the potential effects of increased levels of these greenhouse gases, including more extreme weather events and melting of polar ice.
Lessons
Work through them in order.
- Composition of clean, dry airState the percentages of the gases in clean, dry air and use them to read and check air-composition data.
- Air pollutants and acid rainTrace carbon monoxide, nitrogen oxides and sulfur dioxide from their sources to their effects, including acid rain.
- The carbon cycleTrace carbon through photosynthesis, respiration and combustion, and explain when removal and release of carbon dioxide balance.
- Greenhouse gases and global warmingExplain how carbon dioxide and methane cause global warming, name their sources and describe the effects.
Practise and check
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