Unit 7: Atmospheric Pollution
Acid deposition mainly affects communities that are downwind from coal-burning power plants.
Downwind: the direction in which the wind is blowing and the air is flowing - wind will carry the acid rain further downwind and have a heavier effect there
Acid rain and deposition can lead to the acidification of soils and bodies of water and corrosion of human-made structures.
Acid rain can affect the pH of the soil as well as enter the water supply - can become dangerous to the land and aquatic organisms in the area
Acid rain and deposition is due to nitrogen oxides and sulfur oxides from anthropogenic and natural sources in the atmosphere.
Acid rain: forms as the NOx and SOx in the atmosphere creates acids with H2O and causes the rainwater to become slightly acidic - as the reaction occurs, the once neutral rainwater will then become acidic when released
Many environmental factors affect the formation of photochemical smog.
Amount of sunlight: more sunlight increases the rate of the conversion to smog Amount of cars: more NOx present results in more of the conversion and formation of smog
Indoor air pollutants that are classified as particulates include asbestos, dust, and smoke.
Asbestos: naturally occurring silicate molecules that can be released into the air and cause cancer - can have small particles which can be absorbed making it into a particulates as it burns
Carbon monoxide is an indoor air pollutant that is classified as an asphyxiant.
Asphyxiant: a nontoxic or minimally toxic gas that can displace oxygen in normal breathing air - carbon monoxide replaces O2 in the body until the person suffocates to death
A catalytic converter is an air pollution control device for internal combustion engines that converts pollutants (CO, NOx, and hydrocarbons) in exhaust into less harmful molecules (CO2, N2, O2, and H2O).
Catalytic converter: an exhaust emission control device that reduces toxic gases from an internal combustion engine into a less toxic pollutant by catalyzing a redox reaction - minimizes the amount of toxic chemicals released into the air since the toxic chemicals are changed into a safer chemical
Through the Clean Air Act, the Environmental Protection Agency (EPA) regulated the use of lead, particularly in fuels, which dramatically decreased the amount of lead in the atmosphere.
Clean Air Act (1967): federal law to regulate all air emissions and minimize pollution Environmental Protection Agency (EPA): federal agency for regulating the environment - removing lead from the gasoline minimized the amount of lead poisoning anticipated
Common combustion air pollutants include carbon monoxide, nitrogen oxides, sulfur dioxide, particulates, and tobacco smoke.
Combustion air pollutants: forms as a result of the combustion process and can be dangerous to the human health - reason why there can be more dangers when there are problems with circulation in the house
Some effects of noise pollution on animals in ecological systems include stress, the masking of sounds used to communicate or hunt, damaged hearing, and causing changes to migratory routes.
In the wild, noise pollution becomes dangerous to animals as it could mess with the animal's natural mating process (sounds/noises) - in humans, can cause auditory effects when the noise exceeds a certain decible for an extended period of time (can cause hearing loss)
Noise pollution is sound at levels high enough to cause physiological stress and hearing loss.
Noise pollution: the negative effect of the sound on animals or humans in a general area - can be dangerous when causing hearing problems
Nitrogen oxide is produced early in the day. Ozone concentrations peak in the afternoon and are higher in the summer because ozone is produced by chemical reactions between oxygen and sunlight.
Ozone: O3 and forms as NOx and O2 in the environment come in contact with sunlight - as more cars arrive in morning for driving to work, the NOx levels hit a high - by afternoon, the ozone levels peak as there is max sunlight in the afternoon
The combustion of fossil fuels releases nitrogen oxides into the atmosphere. They lead to the production of ozone, formation of photochemical smog, and convert to nitric acid in the atmosphere, causing acid rain. Other pollutants produced by fossil fuel combustion include carbon monoxide, hydrocarbons, and particulate matter.
Ozone: an inorganic molecule O3 that forms by O2 being hit with UV and electrical discharges in the atmosphere Photochemical smog: a type of smog that is produced when UV from the sun reacts with nitric oxides in atmosphere - appears as brownish haze mostly during the morning and afternoon - mostly in densely populated area and under warm conditions because of more sunlight means more smog
There are a variety of natural sources of particulate matter.
Particulate matter: small molecules that can be airborne and inhaled which can be dangerous - caused by erosion, volcanic eruptions, etc.
Photochemical smog can harm human health in several ways, including causing respiratory problems and eye irritation.
Photochemical smog contains VOCs which can cause asthma, respiratory issues, etc. - since the haze includes chemicals, it can be extremely dangerous to inhale
Photochemical smog is formed when nitrogen oxides and volatile organic hydrocarbons react with heat and sunlight to produce a variety of pollutants.
Photochemical smog: smog which forms as UV from sun reacts with NOx to create a haze - NOx mostly released from the cars burning their diesel
Exposure to radon gas can lead to radon induced lung cancer, which is the second leading cause of lung cancer in America.
Primary effect of radon gas includes respiratory issues to humans and animals - radoninduced lung cancer is one of the primary effects of the radon gas making it lethal and extremely dangerous to many
Air pollutants can be primary or secondary pollutants.
Primary pollution: pollution forming without sunlight (ie. CO, NOx, particulates, SOx) Secondary pollution: pollution occurring as the pollutants hit sunlight/UV (ie. smog)
Radon-222 is a naturally occurring radioactive gas that is produced by the decay of uranium found in some rocks and soils.
Radon 222: the most stable isotope of radon and can seep int the house from the ground - naturally occurring underground so cannot cause - insulation necessary to block out the radon from entering house and causing poisoning
Radon gas can infiltrate homes as it moves up through the soil and enters homes via the basement or cracks in the walls or foundation. It is also dissolved in groundwater that enters homes through a well.
Radon gas can often enter houses form under the house through cracks or the basement - radon is naturally occurring underground in the ground so cannot be contained - necessary for proper insulation in order to prevent radon gas from entering the house
Methods to reduce air pollutants include regulatory practices, conservation practices, and alternative fuels.
Regulatory practices: regulating the amount of energy each individual has to spend; EPA Conservation practice: switching to hydrogen/electric cars, using energy efficient appliances Alternative: nuclear energy, solar, wind, hydro energy
CO2 appears naturally in the atmosphere from sources such as respiration, decomposition, and volcanic eruptions.
Respiration: humans naturally release carbon as CO2 through breathing, increasing the carbon content Decomposition: carbon returns to the environment as organisms decay Volcanic eruptions: as volcanoes erupt, their magma contains carbon which is subsequently released
Methods to reduce air pollution from coal burning power plants include scrubbers and electrostatic precipitators.
Scrubbers: air pollution control devices that use liquid to remove particulates or gases from clean Electrostatic Precipitators: a device that removes suspended dust particles from gas by applying electrostatic charge and collecting the particles on a charge plate
Photochemical smog often forms in urban areas because of the large number of motor vehicles there.
Since NOx is required for photochemical smog formation, areas with high amounts of cars generate more NOx and thus more smog
Nitric oxides that cause acid deposition come from motor vehicles and coal-burning power plants. Sulfur dioxides that cause acid deposition come from coal-burning power plants.
Sources of NOx stems primarily from the burning of car fuel and coal burning power plants - the NOx is necessary to undergo a chemical reaction in the atmosphere with H2o to form acid rain
Thermal inversion traps pollution close to the ground, especially smog and particulates.
The particulates trapped in the thermal inversion can cause severe respiratory issues - there is no way for the pollution to escape
Regional differences in soils and bedrock affect the impact that acid deposition has on the region—such as limestone bedrock's ability to neutralize the effect of acid rain on lakes and ponds.
The things in the area of the acid ran can affect the effect of the acid rain - some compounds can better neutralize the acid rain so that there is a smaller effect - some regions have more limestone or other compounds
Sources of noise pollution in urban areas include transportation, construction, and domestic and industrial activity
There is usually more noise pollution in urban areas compared to rural - more transportation (cars, planes, trains) - construction (machinery and sites) - industrial activity (factories, machines)
During a thermal inversion, the normal temperature gradient in the atmosphere is altered as the air temperature at the Earth's surface is cooler than the air at higher altitudes.
Thermal inversion: when a layer of warm air settles above a layer of cooler air towards the ground - the warm air holds the pollutants and prevents it from scattering/dispersing - causes long-term pollution and dangers
Photochemical smog can be reduced through the reduction of nitrogen oxide and VOCs.
This can be proven as in areas with more cars have more photochemical smog = LA smog
A vapor recovery nozzle is an air pollution control device on a gasoline pump that prevents fumes from escaping into the atmosphere when fueling a motor vehicle.
Vapor recovery nozzle: devices attached to the pump at gas stations to limit the amount of air pollution - reduces the amount of gas evaporating and contributing to air pollution - reduces the chances of the extra gasoline leaking out and into the environment
Wet and dry scrubbers are air pollution control devices that remove particulates and/or gases from industrial exhaust streams.
Wet scrubbers: introduces dirty gas steam into a fluid (usually water) which removes the pollutants and expels out the cleaner air Dry scrubbers: introduces dirty gas and purifies it into a cleaner form without liquid (usually for acid rain)
Air quality can be affected through the release of sulfur dioxide during the burning of fossil fuels, mainly diesel fuels.
Burning of diesel oil for cars releases a high amount of SOx which contributes heavily to the air pollution in an area - thus, to minimize, it is necessary to switch to cleaner forms of energy like hydrogen/electric
Coal combustion releases air pollutants including carbon dioxide, sulfur dioxide, toxic metals, and particulates
Coal is combusted to release energy and for the heat generated to form electricity - in the combustion process, releases a large amount of air pollution (CO, CO2, NOx, SOx)
Common human-made indoor air pollutants include insulation, Volatile Organic Compounds (VOCs) from furniture, paneling and carpets; formaldehyde from building materials, furniture, upholstery, and carpeting; and lead from paints.
Formaldehyde: naturally occurring organic compound used in building materials - mostly, can resignate in the furniture long after it's made Lead: can lead to lead poisoning - used to occur more from lead being present in the paints but now there's no lead in paint
Indoor air pollutants can come from natural sources, human-made sources, and combustion.
Natural sources: volcanic eruptions, radon from ground Human-made sources: construction/demolition projects Combustion: releases small particles as it burns
Common natural source indoor air pollutants include radon, mold, and dust.
Radon: emits from underground and naturally occurs in houses that are not well insulated Dust: particulates can arise from the dust
Volatile Organic Compounds (VOCs), such as formaldehyde and gasoline, evaporate or sublimate at room temperature. Trees are a natural source of VOCs.
VOCs: compounds that easily become vapors or gases and are organic compounds that have high vapor pressures at room temperature - VOCs can contribute to the amount of air pollution as well as VOCs are a primary pollutant
