types of air pollution

primary pollutants

Some primary pollutants are natural, such as volcanic ash. Dust is natural but exacerbated by human activities; for example, when the ground is torn up for agriculture or development. Most primary pollutants are the result of human activities, the direct emissions from vehicles and smokestacks. Primary pollutants include: Carbon oxides include carbon monoxide (CO) and carbon dioxide (CO2 ) (Figure 1.1). Both are colorless, odorless gases. CO is toxic to both plants and animals. CO and CO2 are both greenhouse gases. Nitrogen oxides are produced when nitrogen and oxygen from the atmosphere come together at high temper- atures. This occurs in hot exhaust gas from vehicles, power plants, or factories. Nitrogen oxide (NO) and nitrogen dioxide (NO2 ) are greenhouse gases. Nitrogen oxides contribute to acid rain. Sulfur oxides include sulfur dioxide (SO2 ) and sulfur trioxide (SO3 ). These form when sulfur from burning coal reaches the air. Sulfur oxides are components of acid rain. Particulates are solid particles, such as ash, dust, and fecal matter (Figure 1.2). They are commonly formed from combustion of fossil fuels, and can produce smog. Particulates can contribute to asthma, heart disease, and some types of cancers. Lead was once widely used in automobile fuels, paint, and pipes. This heavy metal can cause brain damage or blood poisoning. High CO2 levels are found in major metropolitan areas and along the major interstate highways. Particulates from a brush fire give the sky a strange glow in Arizona.



secondary pollutants

Any city can have photochemical smog, but it is most common in sunny, dry locations. A rise in the number of vehicles in cities worldwide has increased photochemical smog. Nitrogen oxides, ozone, and several other compounds are some of the components of this type of air pollution. Photochemical smog forms when car exhaust is exposed to sunlight. Nitrogen oxide is created by gas combustion in cars and then into the air (Figure 1.3). In the presence of sunshine, the NO2 splits and releases an oxygen ion (O). The O then combines with an oxygen molecule (O2 ) to form ozone (O3 ). This reaction can also go in reverse: Nitric oxide (NO) removes an oxygen atom from ozone to make it O2 . The direction the reaction goes depends on how much NO2 and NO there is. If NO2 is three times more abundant than NO, ozone will be produced. If nitric oxide levels are high, ozone will not be created. The brown color of the air behind the Golden Gate Bridge is typical of California cities, because of nitrogen oxides. Ozone is one of the major secondary pollutants. It is created by a chemical reaction that takes place in exhaust and in the presence of sunlight. The gas is acrid-smelling and whitish. Warm, dry cities surrounded by mountains, such as Los Angeles, Phoenix, and Denver, are especially prone to photochemical smog. Photochemical smog peaks at midday on the hottest days of summer. Ozone is also a greenhouse gas.


types of air pollution

The two types of air pollutants are primary pollutants, which enter the atmosphere directly, and secondary pollutants, which form from a chemical reaction.

instructional diagrams

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dust is a natural air pollutant that is increased by human activities.

-->  a) true

b) false

which of these is not a primary pollutant?

a) nitrogen oxides

b) methane from livestock

-->  c) ozone

d) particulates

carbon compounds, such as dioxin and methane, are known as ____.

a) volatile inorganic compounds

-->  b) volatile organic compounds

c) volatile inorganic carbons

d) secondary pollutants

air pollutants

a) muck up the air.

b) cause acid rain.

c) contribute to human health problems.

-->  d) all of these.

sulfur oxides and nitrogen oxides are

a) ozone destroying compounds.

-->  b) components of acid rain.

c) toxic to human neurological systems.

d) all of these.

all air pollutants, except particulates, are brownish gases.

a) true

-->  b) false

secondary pollutants are most common in warm, arid cities surrounded by mountains.

-->  a) true

b) false

how is ozone created from car exhaust?

-->  a) nitrogen oxide from the tailpipe, releases an oxygen ion, which combines with an

b) carbon dioxide from the tailpipe, releases an oxygen ion, which combines with an oxygen molecule to create o3.

c) cfcs lose a chlorine ion, which breaks apart an oxygen molecule, to create two oxygen ions to attach to another oxygen molecule to create o3.

d) none of the above.

ozone is beneficial in the _, but a secondary pollutant in the _.

a) mesosphere; troposphere

b) mesosphere; stratosphere

-->  c) stratosphere; troposphere

d) troposphere; stratosphere

diagram questions

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