Exam 3 ENV
Secondary pollutant
not emitted directly, but form when other pollutants react in the atmosphere. Examples of secondary pollutants are ozone, acid rain, and smog.
the sources and sinks of greenhouse gases discussed in the readings
A source is any process or activity through which a greenhouse gas is released into the atmosphere. Both natural processes and human activities release greenhouse gases. A sink is a reservoir that takes up a chemical element or compound from another part of its natural cycle
Reactant
A substance that is altered or incorporated into another substance in a chemical reaction, especially a directly reacting substance present at the initiation of the reaction
Catalyst
A substance, usually used in small amounts relative to the reactants, that modifies and increases the rate of a reaction without being consumed in the process
the environmental effect of nitrogen deposition in rain
Acid rain comes in many forms: rain, snow, sleet, hail and fog (wet deposition), and as deposits of acid particles, aerosols and gases (dry deposition). It is formed when sulfur dioxide (SO2) and nitrogen oxides (NOx) combine with moisture in the atmosphere to produce sulfuric acid and nitric acid. (yvette)
formation of acid rain and the compounds involved and produced
Acid rain is caused by a chemical reaction that begins when compounds like sulfur dioxide and nitrogen oxides are released into the air. These substances can rise very high into the atmosphere, where they mix and react with water, oxygen, and other chemicals to form more acidic pollutants, known as acid rain
industrial smog vs photochemical smog
Both industrial smog and photochemical smog are forms of air pollution. Although both appear to the eye as yellow-brown haze, they differ in two key ways: chemistry and composition. Industrial smog typically exists in urban areas where factories burn fossil fuels such as coal, which creates smoke and sulfur dioxide that mix with fog droplets to create a thick blanket of haze close to the ground. Photochemical smog occurs in drier, sunny areas and forms because of increased usage of all fossil fuels, including gasoline, and the burning of trees and organic waste. These emissions combine in the presence of sunlight to create a noxious environment, which can be harmful to human health.
how carbon dioxide is removed from the atmosphere
Carbon Dioxide (CO2) - refers to a number of technologies, the objective of which is the large-scale removal of carbon dioxide from the atmosphere. Such technologies remain largely theoretical. Among such technologies are bio-energy with carbon capture and storage, biochar, ocean fertilization, enhanced weathering, and direct air capture when combined with storage. CDR is a different approach than removing CO2 from the stack emissions of large fossil fuel point sources, such as power stations. The latter reduces emission to the atmosphere but cannot reduce the amount of carbon dioxide already in the atmosphere. As CDR removes carbon dioxide from the atmosphere, it creates negative emissions, offsetting emissions from small and dispersed point sources such as domestic heating systems, airplanes and vehicle exhausts
how temperature affects air pollutio
Colder temperatures can cause a temperature inversion. With a temperature inversion, cold air is trapped at the surface underneath a layer of warm air. This causes the pollutants to be trapped at the surface since there is no warm rising air to disperse it. Warmer temperatures can cause increased rates of oxidation which causes faster production of ground-level ozone.
Nitrogen Dioxide
Health Effect: Diffuses into the epithelial lining fluid (ELF) of the respiratory epithelium; Can cause bronchoconstriction, inflammation, reduced immune response, effects on the heart, irritations and burns upon direct exposure to the skin. 10 - 20ppm: mild irritation of the nose and throat 25 - 50ppm: edema leading to bronchitis and pneumonia >100ppm: death due to asphyxiation from fluid in the lungs. Environmental Effect: Reacts with Volatile Organic Compounds (VOCs) and CO to form ground-level ozone. a reddish-brown poisonous gas used in the manufacture of nitric acid. It is also an air pollutant, a constituent of untreated automobile exhaust
Particulate Matter (PM
Health Effect: Major cause of cardiovascular disease, cardiopulmonary complications and and are suspected to cause cancer, specifically in the lungs. Environmental Effect: Particles scatter light by altering the direction of radiation beams without absorbing radiation, causing limited visibility in the atmosphere. PM scatter more efficiently when there is high water-vapor content in the air. Certain PM have a cooling effect because they scatter radiation without absorbing it. Other PM (ex. Soot) absorb radiation and contribute to the warming effect. All PM serve as condensation nuclei for cloud droplets, increasing the amount of radiation reflected back into space by clouds.
Carbon Monoxide
Health Effect:CO can cause headache, dizziness, vomiting, and nausea; over long periods of time has also been linked with increased risk of heart disease Environmental Effect: Does not directly alter global temperature; indirectly contributes to the buildup of some greenhouse gases in the troposphere. It reacts with certain chemicals that would otherwise destroy methane and ozone. This chemical reaction helps elevate the concentrations of methane and ozone.
the environmental impacts of acid rain
It can have harmful effects on plants, aquatic animals and infrastructure. Acid rain is caused by emissions of sulphur dioxide and nitrogen oxide , which react with the water molecules in the atmosphere to produce acids. Some governments have made efforts since the 1970s to reduce the release of sulphur dioxide and nitrogen oxide into the atmosphere with positive results. Nitrogen oxides can also be produced naturally by lightning strikes, and sulphur dioxide is produced by volcanic eruptions
the pH range that qualifies 'acid rain'
Normal, clean rain has a pH value of between 5.0 and 5.5, which is slightly acidic. However, when rain combines with sulfur dioxide or nitrogen oxides—produced from power plants and automobiles—the rain becomes much more acidic. Typical acid rain has a pH value of 4.0
the primary sources of each air pollutant and their secondary products
Primary pollutants are emissions that directly cause air pollution in the form in which they are released at the source. Certain primary pollutants can react with other elements or compounds, creating new chemicals that are known as secondary pollutants.
Describe the conditions that contribute to greenhouse gas production and uptake
Production: Fossil Fuel combustion (CO2, CH4 Methane, N2O) Cement manufacturing, deforestation. (CO2) Decomposition in landfills, wetlands, biomass burning (Methane and N2O). Uptake: Plant and phytoplankton photosynthesis. (CO2) Oxidation by hydroxyl radicals (CH4 Methane) Reaction with O2 in the atmosphere to form NO which depletes ozone. (N2O)
fate of Nitrogen Dioxide when emitted
Reacts with Volatile Organic Compounds (VOCs) and CO to form ground-level ozone. Eventually oxidized to nitric acid (HNO3) which contributes to acid deposition and aerosol formation.
how scientists study past and current climate conditions to make predictions about the future
Scientists measure conditions such as temperature and precipitation directly in order to learn more about climate change. Proxy indicators such as air bubbles in ice indicate past climates. Computerized climate models can imitate climate processes. Scientists learn about climate and how it has changed by studying climates of the past. By analyzing changes that have occurred in the earth's temperature over time, scientists can gain a better understanding of global warming, and make determinations about its possible causes. Scientists have discovered ways to study the earth's climate, going back as far as thousands, or even millions, of years. Those who specialize in studying ancient climates are known as paleoclimatologists, a name derived from the Greek root word paleo , which means ancient. Paleoclimatologists use natural elements in the environment to find "proxy climate data" related to the past. When they study these types of data, these scientists typically use several different methods, so they are assured of forming the most accurate analysis possible.
sulfur dioxide affects human health
Sulfur dioxide irritates the skin and mucous membranes of the eyes, nose, throat, and lungs. Inflammation of respiratory system.
the environmental conditions that influence the formation and toxicity of smog
Sunlight and temperature greater than 18ºC. Warmer weather causes more oxidation which causes increased ground-level ozone formation. Thermal Inversion: When a layer of warm air hangs above a layer of cooler air near the ground. Increases the concentration of smog at the surface. Areas that are in valleys and have less wind flow have less pollutant dispersion, which causes the air pollution to concentrate in that location. At high-altitude, fuel doesn't burn as efficiently, causing more VOCs.
Wet deposition
The transfer of pollutants from the atmosphere to the earth by inclusion or solution in precipitation. Wet deposition typically involves gases and particulate matter, and especially acidic compounds or radioactive particles
how Chlorofluorocarbons are removed from the atmosphere
This work addresses the possibility of processing the Earth's atmosphere (5×1015 metric tons) to remove the chlorofluorocarbons (CFCs). It is the chlorine atoms, from the ultraviolet photolysis of CFCs in the stratosphere, that are held responsible for catalyzing the thinning of the Earth's protective ozone layer. In addition, it is estimated that the contribution of CFCs to the ''greenhouse effect'' and global warming is already 40% that of carbon dioxide and the figure is estimated to rise to 60% in the next four decades. This study surveys the use of powerful lasers to break up CFCs, while still in the troposphere, by infrared multiphoton dissociation. The reaction products would be expected to dissolve in rain droplets. One major limitation to this highly speculative scheme is posed by stimulated rotational Raman scattering of the laser beams. As presently perceived, the cost of installation and operation of the elaborate laser facilities would be certainly prohibitive unless a factor of 5 or 10 improvement in overall efficiency can be found
Nitrogen gas (N2)
a colorless tasteless odorless element that as a diatomic gas is relatively inert and constitutes 78 percent of the atmosphere and that is a constituent of organic compounds found in all living tissues.
Carbon dioxide
a colorless, odorless gas produced by burning carbon and organic compounds and by respiration. It is naturally present in air (about 0.03 percent) and is absorbed by plants in photosynthesis
Carbon monoxide (CO)
a colorless, odorless toxic flammable gas formed by incomplete combustion of carbon
Nitrous oxide (N2O)
a colorless, sweet-smelling, sweet-tasting, nonflammable, slightly water-soluble gas, N2O, that sometimes produces a feeling of exhilaration when inhaled: used chiefly as an anesthetic in dentistry and surgery, in the manufacture of chemicals, and as an aerosol
sulfur dioxide, nitrogen dioxide, and carbon monoxide
air pollutants of primary concern in urban settings; emitted directly into the air from fossil fuels such as fuel oil, gasoline, and natural gas that are burned in power plants, automobiles, and other combustion sources
Chlorofluorocarbons
any of a class of compounds of carbon, hydrogen, chlorine, and fluorine, typically gases used in refrigerants and aerosol propellants. They are harmful to the ozone layer in the earth's atmosphere owing to the release of chlorine atoms upon exposure to ultraviolet radiation. Nitrogen oxides (NOx=NO3 and NO2)
primary particular matter
are derived from both human and natural activities. These types of activities include agricultural operations, industrial processes, combustion of wood and fossil fuels, construction and demolition activities, and entrainment of road dust into the air. Natural sources also contribute to the overall problem including windblown dust and wildfires.
Volatile organic compounds (VOC)
are emitted as gases from certain solids or liquids. VOCs include a variety of chemicals, some of which may have short- and long-term adverse health effects. Concentrations of many VOCs are consistently higher indoors (up to ten times higher) than outdoors. VOCs are emitted by a wide array of products numbering in the thousands
Primary pollutant
are emitted directly into the air from sources such as S02 N02 and CO
secondary particulate matter
are sources that directly emit air contaminants into the atmosphere that form or help form PM; these include SOx, NOx, VOCs, and ammonia
how methane is removed from the atmosphere
by contrast, is mostly removed from the atmosphere by chemical reaction, persisting for about 12 years. Thus although methane is a potent greenhouse gas, its effect is relatively short-lived.
environmental effects of sulfur dioxide
causes acid rain and aerosols
how water vapor is removed from the atmosphere
comes out of the air, it often causes precipitation like rain and snow. First, when water vapor is cooled it transform into tiny droplets of liquid water or ice crystals that grab onto particles of dust in the atmosphere. Tons of these little droplets or ice crystals make clouds. When you look at clouds from the ground, the tiny droplets and ice are too far away to see, but many of them together look like a cloud. If the droplets or ice crystals get large enough, they fall from the sky as rain or snow.
Eutrophication
excessive richness of nutrients in a lake or other body of water, frequently due to runoff from the land, which causes a dense growth of plant life and death of animal life from lack of oxygen
source of atmospheric sulfur dioxide
fuel containing sulfur is burned, during metal melting or as a product of other industrial processes. More than 65% of SO2 produced is from coal burning
Dry Deposition
he deposition of pollutants, including gases and particulate matter, as they settle out of the atmosphere or are absorbed by plant tissues
Particulate matter
is a complex mixture of extremely small particles and liquid droplets that get into the air. Once inhaled, these particles can affect the heart and lungs and cause serious health effects
pH
is a logarithmic scale used to specify the acidity or basicity of an aqueous solution. It is approximately the negative of the base 10 logarithm of the molar concentration, measured in units of moles per liter, of hydrogen ions
Sink
is a reservoir that takes up a chemical element or compound from another part of its natural cycle
Source
is any process or activity through which a greenhouse gas is released into the atmosphere.
how nitrous oxide is removed from the atmosphere
is destroyed in the stratosphere and removed from the atmosphere more slowly than methane, persisting for around 114 years.
methane
is gas that is found in small quantities in Earth's atmosphere. Methane is the simplest hydrocarbon, consisting of one carbon atom and four hydrogen atoms. Methane is a powerful greenhouse gas. Methane is flammable, and is used as a fuel worldwide
Industrial Smog
is the black-brown colored haze that is in the air that can be seen over some cities. It is mostly visible in the summer. The smog itself is composed of sulfur dioxide, small amounts of sulfuric acid, and suspended particles from the burning of coal and oil
Photochemical smog
is the chemical reaction of sunlight, nitrogen oxides and volatile organic compounds in the atmosphere, which leaves airborne particles and ground-level ozone. This noxious mixture of air pollutants may include the following: Aldehydes.
fate of carbon monoxide when emitted
residence time of several months in the atmosphere. Eventually reacts with O2 to form CO2
