Chapter 15 Environmental

What is sulfur dioxide?

A corrosive gas that comes primarily from combustion of fuels such as coal and oil.

What are asbestos?

A long, thin, fibrous silicate mineral with insulating properties.

What is the third step in stratospheric ozone for formation and break down?

Ozone is broken down into O2 and free oxygen atoms when it absorbs both UV-C and UV-B ultraviolet light. O3 + UV-B or UV-C > O2 + O. The free oxygen atoms and molecular oxygen O2 may again react to produce ozone molecules.

Why is particulate matter a problem?

Particulate matter scatters and absorbs sunlight. If the atmospheric concentration is higher, as it would be immediately following a large forest fire or volcanic irruption, the reduction of incoming solar radiation in the region will affect photosynthesis.

What can thermal inversions create?

Pollution events that are particularly common in some cities, where high concentrations of vehicle exhaust and industrial emissions are easily trapped by the inversion layer.

What is particulate matter?

Solid or liquid particles suspended in the air.

How is photochemical smog created?

The first part of the process takes place during the day, 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 decreases, nitrogen oxide is still present in the atmosphere and the ozone recombines with the NO, and reforms into O2 + NO2.

What do VOCs play a role in?

The formation of photochemical oxidants such as ozone.

How do humans become exposed to VOCs?

They are used in building materials, furniture, and other home products such as glues and paints.

What is the U.S. Clean Air Act of 1970?

The act ultimately identified six pollutants that significantly threaten human well-being, ecosystems, and structures; sulfur dioxide, nitrogen oxides, carbon monoxide, particulate matter, tropospheric ozone, and lead.

What is thermal inversion?

When a relatively warm layer of air at mid-altitude covers a layer of cold, dense air below. The warm inversion layer traps emissions that then accumulate beneath it.

What is electricity generation?

50% fueled by coal, the major source of anthropogenic sulfur dioxide.

What are photochemical oxidants?

A class of air pollutants formed as a result of sunlight acting on compounds such as nitrogen oxides and sulfur dioxide.

Why is the major source of ozone in the stratosphere?

A class of anthropogenic compounds known as clorofluorocarbons (CFCs).

What are chlorofluorocarbons?

A family of organic compounds who is properties make them ideal for use in refrigeration and air-conditioning, as propellants an aerosol cans to deliver ingredients such as deodorant and insect republic, and as blowing agents to inject air into foam products like Styrofoam cups and foam insulation.

What is the second step in CFC break down?

A free oxygen atom pulls the oxygen atom from ClO, liberating the chlorine and creating one oxygen molecule. The free chlorine molecule is ready to break down more ozone. ClO + O > Cl + O2.

How is ozone created?

An example of a secondary pollutant. Formed in the atmosphere as a result of emission of the primary air pollutants NOx and VOCs in the presence of sunlight.

What were asbestos used for?

As an insulator on steam and hot water pipes and then shingles for the siding of buildings.

What is carbon dioxide?

Carbon dioxide is a colorless, odorless gas that is formed during the complete combustion of most matter, and biomass it is released during respiration.

Why is carbon monoxide bad?

Carbon monoxide can be a significant component of air pollution in urban areas. It also can be a dangerous indoor air pollutant will exhaust systems are natural gas heaters malfunction and, primarily in developing countries, weather may be poor ventilation when cooking with, charcoal, or kerosene.

What is carbon monoxide?

Carbon monoxide is a colorless, odorless gas that is formed during incomplete combustion of most matter, and therefore is a common immersion in vehicle exhaust, and most other combustion processes.

What is the first step in CFC breakdown?

Chlorine breaks ozones bonds and pulls off of one Adam of oxygen, forming a chlorine monoxide molecule and carbon dioxide. O3 + Cl > ClO + O2.

O3 + O > 2O2

Chlorine is acting here as a catalyst, bringing about the reaction without getting used up itself. One chlorine atom can catalyze the breakdown of as many as 100,000 ozone molecules before it leaves the stratosphere. This reaction converts ozone to molecular oxygen O2 but does not involve the absorption of any UV light; the O zone that chlorine breaks down is no longer available to absorb incoming UVB radiation.

What are hydrocarbons?

Compounds that contain carbon-hydrogen bonds, such as gasoline, lighter fluid, dry-cleaning fluid, oil-based paints, and perfumes.

What is photochemical smog?

Dominated by oxidants such as ozone and is sometimes called Los Angeles type smog or brown smog.

What is sulfurous smog?

Dominated by sulfur dioxide in sulfate compounds and is sometimes called London type smog or gray smog.

How does atmospheric temperature influence the formation of smog?

Emissions of VOCs increase as the temperature increases. NOx emissions from electric utilities also increase as air-conditioning demands for electricity increase on the hottest days.

What is atmospheric brown cloud?

The combination of particulate matter and ozone.

What is atmospheric brown cloud derived from?

The combustion of fossil fuels and burning biomass.

What happens in the ozone cycle when petrochemicals or VOCs from human activity are absent or limited?

The cycle of formation and destruction generally takes place on a daily basis with relatively small amounts of photochemical smog formation.

What is air pollution?

The introduction of chemicals, particulate matter, or micro organisms into the atmosphere at concentration is higher enough to harm plants, animals, and materials such as buildings, or to alter ecosystems.

What is ozone?

The most abundant in most frequently measured photo chemical oxygen in the troposphere.

What is the brownish tint of atmospheric brown clouds caused by?

The pretense of black or brown light absorbing carbon particles and/or nitrogen dioxide.

What is one of the most innovation aspects of the Clean Air Aspect?

The provisions for the buying and selling of allowances that authorized the owner to release a certain quantity of sulfur. Such an allowance authorizes a power plant or industrial source to emit one ton of SO2 during a given year. Sulfur allowances are awarded annually to existing sulfur emitters proportional to the amounts of sulfur they were emitting before 1990, and the emitters are not allowed to emit more sulfur than the amount for which they have permits.

What is acid deposition?

The reaction between water and atmospheric carbon dioxide lowers the pH of precipitation from 7 to 5.6.

What are some of the features that make CFCs ideal refrigerants?

They are extremely stable, inner, non-toxic, and non-flammable.

Why are photochemical oxidants harmful?

They are generally harmful to plant tissue, human respiratory tissue, and construction materials. Attention is frequently focused on ozone which is three oxygen bonds bound together.

How are asbestos in the manufactured form?

They are relatively stable and not dangerous until disturbed. When insulating materials become old or are damaged or disrupted, the fine fibers can become airborne and can enter the respiratory tract.

What happens in the ozone cycle when VOCs are present?

They combine with nitrogen oxide. This means the NO is not available to break down ozone by recombining with it and a larger amount of ozone accumulates.

Why are the pollution control devices also bad?

They require the use of more fuel and result in increased carbon dioxide emissions.

What are anthropogenic emissions?

Transportation, on-road vehicles, are the largest source of carbon monoxide and nitrogen oxides.

What is the first step in stratospheric ozone formation and break down?

UV-C radiation breaks the bonds holding together the oxygen molecule, leaving two free oxygen atoms. O2 + UV-C > 2O. This only happens to a small fraction of oxygen molecules at any given time, so most of the molecular oxygen O2 remains unaffected in the atmosphere.

What are electrostatic precipitators?

Use an electrical charge to make particles coalesce so they can be removed. Polluted air enters the precipitator and the electrically charged particles within are attracted to negative or positive charges on the sides of the precipitator. The particles collect and relatively clean gas exits the precipitator.

What is a scrubber?

Uses a combination of water and air that actually separates and removes particles. Particles are removed in the scrubber in a liquid or sludge form and clean gas exits. Borrowing from the concept utilized in the electrostatic precipitator, particles are sometimes ionized before entering the scrubber to increase its efficiency. Scrubbers are also used to reduce the emissions of sulfur dioxide.

Why are VOCs not necessarily considered hazardous?

VOCs given off by conifer trees cause no direct harm. VOCs are not currently considered a criteria air pollutant, but because they can lead to the formation of photochemical oxidants, they have the potential to be harmful and are therefore an air pollution concern.

What are volatile organic compounds?

VOCs. Organic compounds that become vapors at typical atmospheric temperatures.

Where does particulate matter come from naturally?

Volcanoes, forest fires, and dust storms.

What do volcanoes naturally emit?

Sulfur dioxide, particulate matter, carbon monoxide, and nitrogen oxides.

Why is stratospheric ozone important?

A protective layer of oxygen and ozone in the stratosphere absorbs over 99% of all incoming UV-B and UV-C radiation, allowing life to exist on land in its current form.

What is the Montreal protocol on substances that deplete the ozone layer?

A signed agreement in 1987 committed to concrete steps toward a solution and revolving to reduce CFC production 50% by the year 2000. Moreover, a series of increasingly stringent amendments was eventually signed by more than 180 countries requiring the elimination of CFC production and use in the developed world by 1996.

What do living plants release?

A variety of VOCs, including ethylene and terpenes.

What does exposure to indoor air pollution from cooking and heating increase the risk of?

Acute respiratory infections, pneumonia, bronchitis and even cancer.

Why are CFCs harmful to the stratosphere?

After release into the troposphere, a CFC molecule does not degrade, dissolve in water, or undergo any significant chemical change, but slowly circulates in the atmosphere. When it reaches the stratosphere, the ultraviolet radiation present is energetic enough to break the bond connecting chlorine to the CFC molecule, which can then undergo reactions with ozone and three oxygen atoms.

What are fabric filters?

Allows gases to pass through them but remove particulate matter.

Where does sulfur dioxide come from?

Because all plants and animals contain sulfur in varying amounts, the fossil fuel's derived from their remains contain sulfur. When these fuels are combusted, the sulfur combines with oxygen to form sulfur dioxide. Sulfur dioxide can also be released during volcanic irruption's and during forest fires.

What is sick building syndrome?

Because new buildings contain many products made with synthetic materials and glues that may not have fully dried out, a significant amount of offgassing occurs. Sick building syndrome has been observed particularly in office buildings, where large numbers of workers have reported a variety of maladies such as headaches, nausea, throat or eye irritations, and fatigue.

Why does conversion to secondary pollutants occur faster in wet environments?

Because solar radiation provides energy for many of these transformations, and because water is usually involved.

Why were the six pollutants called criteria air pollutants?

Because under the clean air act, the EPA must specify allowable concentrations of each polluted.

What is the cause of the formation of the ozone hole in the Antarctic?

Extremely cold weather conditions during the polar winter causes a buildup of ice crystals mixed with nitrogen oxide providing the perfect surface for the formation of the stable molecule CL2, which accumulates is atmospheric chlorine interacts with the 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. Because almost no ozone had been formed in the dark of the polar winter, a large hole occurs. Only after the temperatures warm up and the chlorine gas gets diluted by air from outside of the polar region does the hole diminish.

What is the standard for ozone?

For each locality in the US, the average ozone concentration for any 8-hr period should not exceed 0.075 parts of ozone per million parts of air by clime more than 4 days per year, averaged over a 3-year period.

What is the most toxic VOC?

Formaldehyde which is used widely to manufacture a variety of building products such as particleboard and carpeting glue.

How can air pollution occur naturally?

From sources such as a volcanoes and fires, or it can be anthropogenic, from sources such as automobiles and factories.

Where does particulate matter come from?

From the combustion of wood, animal manure in other biofuels, coal, oil, and gasoline. It is most commonly known as a class of pollutants released from the combustion of fuels such as and oil. Diesel powered vehicles give off particulate matter, in the form of black smoke. It can also come from road dust and rock crushing operations.

What is ground-level pollution?

Generally, the term air pollution refers to pollution in the troposphere, the first 16 km of the atmosphere above the surface of Earth. Tropospheric pollution is sometimes called ground level pollution.

What is fluidized bed combustion?

Granulated coal is burned in close proximity to calcium carbonate, reducing sulfur dioxide emissions. The heated calcium carbonate absorbs sulfur dioxide and produces calcium sulfate, which can be used in the production of gypsum wallboard (Sheetrock).

What is UV-B and UV-C radiation?

Have enough energy to cause potentially significant damage to the tissues and DNA of living organisms.

How can nitrogen oxide emissions be decreased?

Hotter burning conditions and the presence of oxygen allow proportionally more nitrogen oxide to be generated per unit of fuel burned. To reduce nitrogen dioxide emissions, burn temps must be reduced and the amount of oxygen must be controlled.

What does particulate matter and photochemical oxidants cause?

Human health problems and economic harm, since poor visibility in popular vacation destinations can reduce tourism revenues for recreation areas, and for businesses such as hotels and restaurants in these areas.

How can humans be exposed to radon?

If it seeps into a hole through cracks in the foundation or soil, or from drinking the water from underlying rock, soil, or groundwater. Radon-222 decays within four days to a radioactive daughter product, Polonium-210. Either the radon or the polonium can attach to dust and other particles in the air and being held.

What are the four specific reasons for sick building syndrome?

In adequate or faulty ventilation, chemical contamination from indoor sources, chemical contamination in the building from outdoor sources, and biological contamination from the inside or outside.

What are sources of lead?

In gasoline and in lead-based paint.

What are secondary pollutants?

Primary pollutants that have undergone transformation in the presence of sunlight, water, oxygen, or other compounds.

What is radon?

Radon-222 is a radioactive gas that occurs naturally from the decay of uranium and exists in granitic and some other rocks and soil's.

What is haze?

Reduced visibility caused primarily in particulate matter from air pollution scatters light.

What is smog?

In the presence of nitrogen oxides, and volatile organic compounds, oh zone reacts to form even more harmful accidents. In the presence of sulfur and nitrogen oxides, oh zone and other photo chemical oxidants can also enhance the formation of certain particulate matter, which contributes to scattering light.

What happens when lower pH from acid deposition leads fo the mobilization of metals?

Indirect effect. Metals bound in the organic or inorganic compounds in soils and sediments are released into surface water.

For plants and animals, what can increased exposure to UVB radiation cause?

It can be harmful to cells, and can reduce photosynthetic activity. In humans, UVB radiation exposure is correlated with increased risks of skin cancer, cataracts and other eye problems, and a suppressed immune system.

What health effects can radon cause and how can it be prevented?

It can cause lung cancer. People should test their homes for airborne radon. If radon levels are high it is important to increase ventilation in the home and sealing cracks in the basement.

How does acid deposition affect humans?

It can harm human-built structures. When the hydrogen ion in acid deposition interacts with limestone or marble, the calcium carbonate reacts with H(+) and gives off Ca (2+). In this process, the calcium carbonate is partially dissolved.

What does exposure to formaldehyde cause in humans?

It has a pungent smell and a high enough concentration in a confined space can cause a burning sensation in the eyes and throat, and breathing difficulties and asthma and some people. It has been shown to cause cancer in lab animals and has been suspected of being a human carcinogen.

Why is sulfur dioxide bad?

It is a respiratory irritant and can adversely affect plant tissue as well.

Why is tropospheric ozone bad?

It is harmful to both plants and animals and causes respiratory inflammation's such as asthma and emphysema.

Why is the complete combustion of matter that produces carbon dioxide more desirable that the incomplete combustion?

It produces carbon monoxide in other areas. Burning fossil feels has contributed additional carbon dioxide to the atmosphere in lead to it becoming a major pollutants.

What is a difficulty in lowering the temp and oxygen in nitrogen oxide emissions?

It results in less-complete combustion, reducing the efficiency of the process and increasing the amount of particulates and carbon monoxide.

What are some actions that have been taken to reduce smog levels?

Reducing the amount of gasoline spilled at gas stations, restrict the evaporation of dry-cleaning fluids, or restrict the use of lighter fluid for starting charcoal barbecues. Reduction in the use of wood-burning stoves or fireplaces that would reduce emissions of nitrogen oxide, particulate matter, VOCs, and CO.

What is the gravitational settling of particulate matter?

Relies on gravity to remove some of the particles as the exhaust travels through the smokestack. Ash residue that accumulates must be disposed of in a landfill. The ash may contain sufficiently high concentrations of metals that require special disposal.

What is the clean air act?

Require that the EPA establish standards to control pollutants that are harmful to human health and welfare.

What are the greatest health risks from asbestos?

Respiratory diseases such as asbestosis and lung cancer found in very high rates among those who have mined asbestos.

Why is indoor air pollution a problem in developing countries?

More than 3 billion people use wood, animal manure or coal indoors for heat and cooking. Biomass and coal are usually burned in open pit fires that lack the proper mix of fuel and air to allow complete combustion. Usually, there is no exhaust system and little or no ventilation in the home, which makes indoor air pollution from carbon monoxide and particulates.

What are sources of NOx?

Motor vehicles in stationary fossil fuel combustion are the primary anthropogenic sources of nitrogen oxides. Natural sources include forest fires, lightning, and microbial action in soils.

What are nitrogen oxides?

NOx. The X indicates that there be either one or two oxygen atoms per nitrogen; nitrogen oxide, a colorless, odorless gas, and nitrogen dioxide, a pungent, reddish brown gas. The atmosphere is 78% nitrogen gas and all combustion in the atmosphere leads to the formation of some nitrogen oxides. Atmospheric nitrogen oxides play a role in forming tropospheric ozone and other components of photochemical smog.

Where does particulate matter come from?

Natural and human-made fires, road dust, and the generation of electricity.

How does acid deposition form?

Nitrogen oxides and sulfur oxide 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 the secondary pollutants nitric acid and sulfuric acid. These compounds break down further, producing nitrate, sulfate, and hydrogen ions to generate the acidity in acid deposition.

What do lightning strikes naturally create?

Nitrogen oxides from atmospheric nitrogen.

What other anthropogenic compounds can contribute to the destruction of stratospheric ozone?

Nitrogen oxides, bro minds, used as fumigants for soil past such as termites, and carbon tetrachloride, formerly used as a cleaning solvent. However, they do not reach the stratosphere as efficiently because they are more reactive in the troposphere.

What do forest fires release?

Particulate matter, nitrogen oxides, and carbon monoxide.

What is UV-A radiation?

Passes through the atmosphere without being absorbed and contributes to skin cancer.

Why is indoor air pollution a problem in developed countries?

People in much of the developed world have begun to spend more and more time indoors. Homes are more tightly insulated, which allows existing air to remain in contact with inhabitants for greater amounts of time. This is in part a result of improved insulation and tightly sealed building envelopes, which have been implemented in order to reduce energy consumption. There are also more materials in the home that are made from plastics and other petroleum based materials they give off chemical vapors.

What are primary pollutants?

Polluting compounds that come directly out of the smokestack, exhaust pipe, or natural emission source. CO, CO2, SO2, NOx, and most suspended particulate matter. Many VOCs as well.

What are the main components of acid deposition?

Sulfate [SO4(2-)] and nitrate [NO3(3-)]. Also secondary pollutants.

How is carbon monoxide hazardous?

When an exhaust system malfunctions, exhaust air escapes into the living room of the house without the inhabitants knowing. In the body, carbon monoxide binds with hemoglobin more efficiently than oxygen, thereby interfering with oxygen transport in the blood Long term causing oxygen deprivation in the brain and death.

What is the second step in stratospheric ozone for formation and break down?

When the O2 reacts with the free oxygen atoms, resulting in ozone. O2 + O > O3. In the presence of ultraviolet radiation, oxygen is converted to ozone.

Why is lead-based paint harmful?

When the paint peels off, the resulting dust or chips can be toxic to the central nervous system and affect learning and intelligence.