Maintaining Air Quality structured questions · SEC G3 Combined Science Chemistry component

Learning objectives

• 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.