Unit 8 - The Atmosphere, Air Quality, and Pollution Control

Atmosphere

The layer of games that envelops our planet and performs many important functions (ecosystem services). Moderates climate, provides oxygen, shields from meteors and solar radiation, transports and recycles water and nutrients

Atmospheric Composition

Mainly nitrogen and oxygen, has changed over geologic time. Humans have increased concentrations of methane and carbon dioxide

Atmospheric Pressure

Force created by a column of air

Exosphere

The outermost layer of Earth's atmosphere, extending from the thermosphere to outer space, where atmospheric pressure is extremely low, temperature is roughly constant

Thermosphere

the layer of Earth's atmosphere above the mesosphere, characterized by high temperatures due to solar radiation absorption, temperature increases rapidly

Mesosphere

The layer of Earth's atmosphere located between the stratosphere and the thermosphere, characterized by decreasing temperatures with altitude and where most meteoroids burn up upon entering the atmosphere.

Stratosphere

Second layer of Earth’s atmosphere, located between troposphere and mesosphere, drier and less dense than the troposphere, ozone layer found here (good ozone)

Troposphere

Lowest layer of earth’s atmosphere, between surface and stratosphere, temperature decreases with height, 80% of the atmosphere’s mass and nearly all of the clouds are found here, (bad ozone)

Temperature Inversions

Phenomena where cool air is trapped below a layer of warm air, occurs with mountains blocking morning sun, cool in shadows. Pollutants become trapped in inversion layers, especially smog and particulates

Inversion Layers

The layers of pollutants that form as a result of temperature inversions, trapping cool air and pollutants close to the ground.

Air Pollutants

Gases and particulate matter added to the atmosphere that cause harm to humans and the environment

Residence Time

The amount of time a pollutant spends in the atmosphere before settling to the ground

Primary Pollutants

Pollutants that are released directly into the atmosphere. Can be both natural (eg volcano) and anthropogenic sources (eg mountaintop removal, factory, car exhaust, house)

Secondary Pollutants

Pollutants that are created through chemical reactions in the atmosphere (require certain temperatures, primary pollutants, moisture, sunlight)

Clean Air Act

Passed in 1963, amended in 1970 and 1990. Funds pollution control research, sets standards for air quality, emissions standards for automobiles and other points sources (forced technology implementation), states required to monitor emissions for air quality and develop, implement, and enforce own regulations to comply with the law

SPLONC

Sulfur Dioxide, Particulate Matter, Lead, Ozone, Nitrogen Dioxide, Carbon Monoxide (6 Criteria Air Pollutants)

Lead

Gasoline additive, low level exposure in children causes anemia, behavioral disorders, lowered IQ, reading and learning disabilities, nerve damage. Adults causes hypertension and cardiovascular disease

Sulfur Dioxide

Colorless gas with a pungent odor, results from the combustion of coal, petroleum, or diesel fuel. Large contributor to acid deposition, causes wheezing, shortness of breath, and chest tightness

Carbon Monoxide

Colorless, Odorless gas. Produced by incomplete combustion of fuel. Vehicles and engines, carbon monoxide binds to hemoglobin in red blood cells, preventing it from binding to and transporting oxygen. can be fatal

Particulate Matter

Solid or liquid particles small enough to be suspended by air, small enough to be inhaled. Can be a primary pollutant (dust and soot) or secondary (sulfates and nitrates). PM 10 particles are less than 10 microns in diameter, PM2.5 are less than 2.5 microns in diameter. Sources are pollen, dust, spores, wildfires, and combustion. Causes lung and breathing difficulties, nonfatal heart attacks, and irregular heartbeats

Tropospheric Ozone

Ground level ozone, secondary pollutant created by the reaction of NOx and VOCs in sunlight. Unstable molecule that can injure living tissues and cause respiratory problems (cough, irritation, shortness of breath)

NAAQS

National ambient air quality standards set by the EPA to protect public health and the environment from harmful pollutants.

Nitrogen Oxides

Nitrogen binded to oxygen, highly reactive reddish-brown, foul smelling gas. Produced during combustion in engines and fossil fuel combustion. Contributes to smog, tropospheric ozone, nutrient pollution, and acid precipitation. contributes to respiratory diseases like asthma

Volatile Organic Compounds (VOCs)

Carbon containing chemicals that vaporize at room temperature can be emitted by engines and solvents. Released from burning any fuel, can react to form secondary pollutants such as smog. Include carcinogens, allergens, immune system damaging compounds

Mercury

Neurotoxin/developmental problems (teratogen), released from coal burning plants

Electrostatic Precipitator

Method of reducing air pollution focused on particulate matter, on top of smokestack. Electrode ionization, particulate matter neutrally charged →becomes negatively charged, attracted to positive plates/electrodes, clean off plates

Scrubber

Method of reducing air pollution focused on NOx, SOx, VOCs, and PMs. Dirty/exhaust gases sprayed with mist and chemicals, reacts with pollutants, mist captures pollutants, sinks down, waste settles, and disposed of as hazardous waste

Catalytic Converters

Attached to cars, reduce air pollution with catalytic metals that convert hydrocarbons, CO, and NOx to water, carbon dioxide, and nitrogen gas, thereby reducing pollutant release

Vapor Recovery Nozzels

Reduce air pollution at fueling stations. Negative pressure created in the underground tank pulls vapors from car’s gas tank into the underground tank, capturing VOCs from the environment

Noise Pollution

Sound levels so high that they cause physiological stress or hearing loss. From transportation, construction, domestic/industrial activity. Cause wildlife stress, masks communication and hunting sounds, hearing loss, and changes in migration routes

Photochemical Smog

Brown smog when sunlight drives chemical reactions between primary pollutants and atmospheric compounds, producing a mixture of over 100 different chemicals. Ozone, NO2. Windless, warm, sunny days provide ideal conditions for the formation of photochemical smog. N2→2N + O →NOx + sunlight →Ozone

Acid Deposition

Result of burning fossil fuels and releasing sulfur dioxide and nitrogen oxides, which react with water and oxygen in the atmosphere to form acids. Accelerated leaching of base cations, allow sulfur and nitrogen to accumulate in soil (over fertilize), increased inorganic aluminum in soil (hinders plant uptake of water and nutrients), and reduced species diversity in abundance of aquatic life

Acid Rain Program

Fights acid deposition, set up emissions trading program for SO2, allocating permits and allowing emitters to buy, sell, or trade allowances. Successfully reduced emissions by 67%, reduced NOx emissions, significantly reduced nitrogen deposition. pH or precipitation improved significantly

UVC

UV radiation that forms ozone and is completely absorbed in the process

UVB

UV radiation that destroys ozone and is mostly absorbed in the process, causes skin cancer

UVA

UV radiation that fully passes through the stratosphere, vitamin D/tan/electrolytes

Halocarbons

Most common form is CFCs, (chlorofluorocarbons) that were produced in 1920s for use in refrigerators, fire extinguishers, propellants for spray cans, and electronics. Mostly nonreactive and assumed safe, but break down ozone layer

Montreal Protocol

1987, international treaty to reduce CFC production, additional amendments passed, and more chemicals added to list. Ozone hole has stabilized, and is expected to fully recover after 2060, model for solving global environmental problems