outdoor air pollution

global warming

Pollutants also affect the atmosphere through their contribution to global warming. Global warming is an increase in the Earths temperature. It is thought to be caused mostly by the increase of greenhouse gases like carbon dioxide. Greenhouse gases can be released by factories that burn fossil fuels. Over the past 20 years, burning fossil fuels has produced about three-quarters of the carbon dioxide from human activity. The rest of the carbon dioxide in the atmosphere is there because of deforestation, or cutting down trees ( Figure 1.4). Trees absorb carbon dioxide during cellular respiration, so when trees are cut down, they cannot remove carbon dioxide from the air. This increase in global temperature will cause the sea level to rise. It is also expected to produce an increase in extreme weather events and change the amount of precipitation. Global warming may also cause food shortages and species extinction.

sources of outdoor air pollution

Most air pollutants can be traced to the burning of fossil fuels. Fossil fuels are burned during many processes, including in power plants to create electricity, in factories to make machinery run, in power stoves and furnaces for heating, and in waste facilities. Perhaps one of the biggest uses of fossil fuels is in transportation. Fossil fuels are used in cars, trains, and planes. Air pollution can also be caused by agriculture, such as cattle ranching and the use of fertilizers and pesticides. Other sources of air pollution include the production of plastics, refrigerants, and aerosols, in nuclear power and defense, from landfills and mining, and from biological warfare.

acid rain

One result of air pollution is acid rain. Acid rain is precipitation with a low (acidic) pH. This rain can be very destructive to wildlife. When acid rain falls in forests, freshwater habitats, or soils, it can kill insects and aquatic life. It causes this damage because of its very low pH. Sulfur oxides and nitrogen oxides in the air both cause acid rain to form ( Figure 1.3). Sulfur oxides are chemicals that are released from coal-fired power plants. Nitrogen oxides are released from motor vehicle exhaust. A forest in the Jizera Mountains of the Czech Republic shows effects caused by acid rain. What do you observe?


outdoor air pollution

Air is all around us. Air is essential for life. Sometimes, humans can pollute the air. For example, releasing smoke and dust from factories and cars can cause air pollution. Air pollution is due to chemical substances and particles released into the air mainly by human actions. This pollution affects entire ecosystems around the world. Pollution can also cause many human health problems, and it can also cause death. Air pollution can be found both outdoors and indoors. Outdoor air pollution is made of chemical particles. When smoke or other pollutants enter the air, the particles found in the pollution mix with the air. Air is polluted when it contains many large toxic particles. Outdoor air pollution changes the natural characteristics of the atmosphere. Primary pollutants are added directly to the atmosphere. Fires add primary pollutants to the air. Particles released from the fire directly enter the air and cause pollution ( Figure 1.1). Burning of fossil fuels such as oil and coal is a major source of primary pollutants ( Figure Secondary pollutants are formed when primary pollutants interact with sunlight, air, or each other. They do not directly cause pollution. However, when they interact with other parts of the air, they do cause pollution. For example, ozone is created when some pollutants interact with sunlight. High levels of ozone in the atmosphere can cause problems for humans. Wildfires, either natural or human-caused, release particles into the air, one of the many causes of air pollution. A major source of air pollution is the burn- ing of fossil fuels from factories, power plants, and motor vehicles.



instructional diagrams

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the burning of fossil fuels causes most air pollution.

-->  a. true

b. false

outdoor air pollution changes the natural characteristics of the atmosphere.

-->  a. true

b. false

which of the following processes burns fossil fuels?

a) within power plants to create electricity

b) within factories to operate machinery

c) within furnaces to generate heat

-->  d) all of the above

acid rain is formed from

a) the production of plastics.

b) nuclear power and defense.

-->  c) coal-fired power plants.

d) all of the above

where do most greenhouse gases come from?

a) mostly from a lack of trees

-->  b) mostly from burning fossil fuels

c) mostly from landfills and mining

d) mostly from sulfur oxides and nitrogen oxides

effects of a global temperature increase include

a) species extinction.

b) a rise in sea levels.

c) an increase in extreme weather events.

-->  d) all of the above

which of the following is a source of air pollution?

a) the production of aerosols

b) biological warfare

c) cattle ranching

-->  d) all of the above

diagram questions

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