APES Chapter 15 Checkpoint

What is acid deposition?

Acid deposition refers to deposition with a pH lower than 5.6. Acid deposition is largely the result of human activity. Although natural processes such as volcanoes may also contribute. Acid deposition is also called acid rain.

How does an inversion layer influence air pollution events?

An inversion layer is a warm layer that traps emissions that then accumulate beneath it. These trapped emission often cause a severe pollution event. Thermal inversions can also lead to other forms of pollution. For example, in the northern Chinese city of Tianjin, 1000 people suffered carbon monoxide poisoning or respiratory ailments from the polluted air. Eleven died.

What are the major sources of anthropogenic air pollution

Another way thats not natural is through anthropogenic emissions. Anthropogenic sources are human-made sources. The sources of the emission may include on-road vehicles, power plants, industrial process, and waste disposal. This is how pollutants are emitted through anthropogenic sources.

List common sources of indoor air pollution in the developed world.

Asbestos are long, thin, fibrous silicate mineral with insulation properties. The greats health risk from asbestos has been respiratory diseases such as asbestosis and lung caner found in very high rates among those who have mined asbestos. Carbon monoxide can be more dangerous as an indoor pollutant, present as a result of malfunctioning exhaust systems on household heaters, most typically natural gas heaters. Radon is a radioactive gas that occurs naturally from the decay of uranium, exist in granitic and some other rocks and soils in many parts of the world. VOCs are used in building materials, furniture, and other home products such as glues and paints. Formaldehyde is common in new homes and new products made from pressed wood.

What are some approaches to smog reduction?

Control efforts must be directed toward reducing the precursors, or primary pollutants, that contribute to smog. To reduce smog though, with fewer VOCs in the are there are fewer compounds to interact with nitrogen oxides, and thus more nitrogen oxide will be available to recombine with ozone. Most recently, efforts have been to reduce nitrogen oxide emissions, which appears to be a more effective method of controlling smog.

What are the major effects of acid deposition?

Effects of acid deposition may be direct, such as lowering of the pH of lake water, or indirect. Lower pH can also lead to mobilization of metals an indirect effect. People are not harmed by direct contact with precipitation at the acidities commonly experienced in the US or elsewhere in the world. Human health is more affected by the precursors to acid deposition such as sulfur dioxide and nitrogen oxides.

What are the main sources of indoor pollution in the developing world?

First, people in much of the developed world have begun to spend more and more time indoors. Homes have become more tightly insulated, which allows existing air to remain in contact with inhabitants for greater amounts of time. Finally, there are more materials in the home that are made from plastics and other petroleum-based materials that can give off chemical vapors.

How does photochemical smog form?

Forms in the presence of sunlight. If there is an abundance of nitrogen oxides in the atmosphere, but very few VOCs, ozone forms. A few hours later when sunlight intensity decrease, nitrogen oxide is still present in the atmosphere and the ozone recombines with the NO and reforms into O2+ NO2. When petrochemicals or VOCs form human activity are absent or limited, the cycle of ozone formation and destruction generally takes place on a daily basis with relatively small amounts of photochemical smog formation.

What are the major air pollutants?

Major air pollutants include: sulfur dioxide, nitrogen oxides, carbon oxides, particulate matter, lead, ozone, VOCs, and mercury. Each pollutant has different way its emitted into the atmosphere. They also have different effects. A lot of them are bad for humans respiratory systems as well.

What are the two primary pollutants that lead to the formation of acid deposition?

Nitrogen oxides and sulfur dioxide are released into the atmosphere as a result of numerous natural and anthropogenic combustion processes. In the presence of atmospheric oxygen and water, these primary pollutants are transformed, through a series of reactions, into the secondary pollutants nitric acid and sulfuric acid. The latter compounds break down further, producing nitrate, sulfate, and hydrogen ions that generate the acidity in acid deposition.

What is sick building syndrome?

Often in new or renovated buildings sick building syndrome occurs. This is because new buildings contain many products made with synthetic materials and glues that may not have full dried out. A significant amount of off-gassing occurs. A buildup of toxic compounds and pollutants in an airtight space; in buildings with good insulation and tight seal against air leaks, sick building syndrome can occur.

Describe pollution control methods for sulfur dioxide, nitrogen oxides, and particulates.

Pollution control methods include such devices: the baghouse filter, the electrostatic precipitator, and the scrubber. The baghouse filter removes particles by a series of filter bags that physically filter out the particles. In the electrostatic precipitator, particles are given a negative charge. This causes them to be attracted to a positively charge plate, where they are held. Periodically they are removed from the plate and collected for disposal. The scrubber is when particles are "scrubbed" from the exhaust stream by water droplets. A water-particle "sludge" is collected and processed for disposal.

What is the difference between a primary and a secondary pollutant?

Primary pollutants are polluting compounds that come directly out of a source. They include CO, CO2, SO2, NOx, and most suspended particulate matter. Secondary pollutants are primary pollutants that have undergone transformation in the presence of sunlight, water, oxygen, or other compounds. Ozona is an example of a secondary pollutant.

Why is air pollution considered a global system?

Since one of the major repositories for air pollutants in the atmosphere, which envelopes the entire globe. Therefore, we must think of the air pollution system as a global system. In fact, evidence appears to link air pollution across long distances. For example, air pollution in Asia has been responsible for acid rain on the west coast of the U.S.

How does the stratospheric ozone layer form and why is it beneficial?

Stratospheric ozone forms and breaks down naturally in a closed-loop cycle. First, UV-C radiation breaks the bonds holding together the oxygen molecule (O2) leaving two free oxygen atoms. When it reacts with the free oxygen atoms formed in reaction 1 the result is ozone. The net result of these two reactions is that, in the presence of UV radiation, oxygen is converted to ozone. Ozone is broken down into O2 and free oxygen atoms when it absorbs both UV-C and UV-B light. The free oxygen atoms and molecular oxygen O2 may again react to produce ozone molecules; thus, ozone is continuously formed and continuously broken down in the presence of sunlight.

Explain the purpose of sulfur allowances and how they work.

Sulfur allowances are awarded annually to existing sulfur emitters proportional to the amounts of sulfur the were emitting before 1990. The emitters are not allowed to emit more sulfur than the amount for which they have permits. At the end of a given year, the emitter must possess a umber of allowances at least equal to its annual emissions. Sulfur allowances can be bought and sold on the open market by anyone. Overall, this reduces sulfur emissions.

How does the Clean Air Act regulate anthropogenic emissions?

The Clean Air Act and its various amendments require that the EPA establish standars to control pollutants that are harmful to "human health and welfare." The term human health means the health of the human population and inclueds the elderly, children, and sensitive populations such as those with asthma. The term welfare refers to visibility, the status of crops, natural vegetation, animals, ecosystems, and buildings. This act helps regulate anthropogenic emissions by simply setting standards.

What has caused the depletion of the ozone layer?

The formation of a stable molecule CL2 accuulates as atmospheric chlorine interacts with ice crystals. When the Sun reappears in the spring, UV radiation breaks down this molecule into CL again, which in turn catalyzes the destruction of ozone. The overall trend of decreasing stratospheric ozone concentration is not related to temperature, but is caused by the breakdown reactions described earlier that result from increased concentrations of chlorine in the atmosphere. Depletion of ozone layer lets UV-B rays reach earth's surface.

What is photochemical smog?

The formation of photochemical smog/ LA-type brown smog is complex and still not well understood. In the presence of VOCs, ozone will form during the daylight hours. The VOCs combine with nitrogen oxides to form photochemical oxidants. These reduce the amount of ozone that will break down later and contribute to prolonged periods of photochemical smog.

What steps are being taken to reduce ozone depletion?

There are many steps being taken to reduce ozone depletion. A series of increasingly stringent amendments were eventually signed by more than 180 countries. These amendments required the elimination of CFC production and use in the developed world by 1996. Although some developing nation were exempted from this strict deadline. In total, the protocol addressed 96 ozone-depleting compounds.

What are the major natural sources of air pollution?

There are several ways pollutants are emitted into the air. Within the emission process the pollutants initally come from a source. The main natural sources of air pollution are volcanoes, lightning strikes, forest fires, and plants. These all naturally emit pollutants.