Environmental Science: Atmosphere, Climate Change, Air Pollution, and Water Resources

Comprehensive practice flashcards covering atmospheric zones, albedo, greenhouse gases, climate change observations and models, Clean Air Act criteria pollutants, indoor and outdoor air pollution, and freshwater resources and pollution.

What is the key difference between weather and climate?

Weather refers to short-term, day-to-day atmospheric conditions in a specific locality, whereas climate describes the long-term patterns, averages, and extremes of weather over extended periods.

What are the four primary zones of Earth's atmosphere from lowest to highest altitude?

The troposphere, stratosphere, mesosphere, and thermosphere.

In which atmospheric zone do most weather events occur?

The troposphere.

In which atmospheric zone does the greenhouse effect primarily take place?

The troposphere.

In which atmospheric zone is the protective ozone layer located?

The stratosphere.

Which atmospheric zone contains the majority of Earth's air molecules and water vapor?

The troposphere.

What is albedo, and which surfaces exhibit high versus low albedo?

Albedo is the reflectivity of a surface to solar radiation. Fresh snow has a very high albedo, reflecting most sunlight, whereas open water, dark soils, asphalt, and forests have low albedo, absorbing the majority of solar energy.

Describe an example of a positive feedback loop contributing to global climate change.

As temperatures rise, Arctic sea ice melts, exposing darker open water. The exposed water has a lower albedo, absorbing more solar radiation, which warms the ocean and accelerates further ice melt.

Which form of radiation makes up the majority of solar radiation that reaches Earth's surface?

Visible light.

What type of radiation is emitted and reemitted by Earth's surface into the atmosphere?

Infrared radiation (longwave thermal radiation).

How do greenhouse gases in the atmosphere trap heat?

Greenhouse gases absorb outgoing infrared radiation reemitted from Earth's ground and reradiate thermal energy back toward the surface, keeping the lower atmosphere warm.

How have human activities altered the natural greenhouse effect?

Human activities, particularly the burning of fossil fuels, deforestation, and industrial practices, have increased concentrations of greenhouse gases, trapping more outgoing infrared radiation and causing global warming.

What are the four major greenhouse gases and their primary anthropogenic sources?

Carbon dioxide ($\text{CO}_2$; fossil fuel combustion and land clearing), methane ($\text{CH}_4$; agriculture, landfills, and natural gas infrastructure), nitrous oxide ($\text{N}_2\text{O}$; agricultural fertilizers and fossil fuel burning), and fluorinated gases/CFCs (refrigerants and industrial chemicals).

Which major greenhouse gas is found in the lowest atmospheric concentration?

Chlorofluorocarbons (CFCs).

Which non-water greenhouse gas is present in the highest concentration in the atmosphere?

Carbon dioxide ($\text{CO}_2$).

Which category of greenhouse gases absorbs the most heat per individual molecule?

Fluorinated gases (such as CFCs and HFCs).

Why do atmospheric levels of $\text{CO}_2$ fluctuate cyclically with the seasons?

During the Northern Hemisphere spring and summer, abundant vegetation takes up large amounts of $\text{CO}_2$ via photosynthesis; during autumn and winter, plant decay releases $\text{CO}_2$ back into the atmosphere.

What are Milankovitch cycles?

Periodic shifts in Earth's orbit, axial tilt, and precession (wobble) that alter the geographic distribution and seasonal intensity of incoming solar radiation over thousands of years.

What observed environmental changes are occurring as a result of global climate change?

An increased amount and intensity of rain and storms, increased duration and severity of droughts, and substantial loss of sea ice in the Arctic Ocean.

How has average global temperature changed during the $20\text{th}$ century?

It has risen in some years and fallen in others, but has increased overall.

What does the acronym IPCC stand for, and what is its role?

Intergovernmental Panel on Climate Change; an international scientific body that evaluates peer-reviewed scientific, technical, and socio-economic data regarding human-induced climate change.

What is the Paris Agreement and what is its central goal?

An international climate accord aimed at keeping global average temperature rise well below $2\,^\circ\text{C}$ above pre-industrial levels, with efforts to limit the increase to $1.5\,^\circ\text{C}$.

What is the 'wedge approach' to reducing atmospheric carbon dioxide concentrations?

A strategy that breaks down the massive task of cutting carbon emissions into smaller, manageable reduction 'wedges' using currently available commercial technologies (such as renewables, vehicle efficiency, and forest preservation).

What is the difference between climate change mitigation and climate change adaptation?

Mitigation involves reducing or preventing the emission of greenhouse gases to slow warming, while adaptation involves adjusting infrastructure, behaviors, and systems to minimize damage from unavoidable climate impacts.

Why are actual atmospheric methane emissions much larger than officially estimated?

Because of significant fugitive leakage and venting from hydraulic fracturing (fracking) operations and natural gas delivery infrastructure.

Match the specific emission activity to the correct greenhouse gas: coal mine leaks, vehicle driving, and landfill decomposition.

Coal mine leaks: Methane ($\text{CH}_4$); vehicle driving: Carbon dioxide ($\text{CO}_2$); landfill decomposition: Methane ($\text{CH}_4$).

How have annual average atmospheric $\text{CO}_2$ levels changed since precise measurements began in $1958$?

Measurements of $\text{CO}_2$ have shown a steady, continuous increase since accurate measurements began.

According to the Pew Report, failure to address climate change could cost citizens trillions of dollars in all areas EXCEPT which factor?

Increased biological productivity (the costs instead stem from infrastructure damage from storms/flooding, heat stress health costs, lost water supplies, and lost agricultural productivity from drought).

According to IPCC models evaluated as of $2007$, which climate parameters accelerated faster than original projections?

Sea level rise, temperature increases, and greenhouse gas emissions all accelerated faster than predicted in the original model.

What is the difference between point source and nonpoint source air emissions?

Point source emissions are discharged from a single, identifiable, localized location (such as an industrial smokestack), whereas nonpoint source emissions are diffuse and scattered over wide areas.

What are fugitive emissions, and which common source is NOT considered a fugitive emission?

Fugitive emissions are leaks that escape unintentionally into the air without passing through a smokestack (e.g., dust from mining, leaking pipes, and natural gas well leaks). Fossil fuel combustion from exhaust pipes or smokestacks is not considered a fugitive emission.

What defines the difference between a primary air pollutant and a secondary air pollutant?

Primary pollutants are substances released directly into the atmosphere in a harmful form, whereas secondary pollutants become hazardous only after undergoing chemical reactions in the air.

What are the six criteria air pollutants designated and regulated under the Clean Air Act?

Carbon monoxide ($\text{CO}$), sulfur dioxide ($\text{SO}_2$), nitrogen oxides ($\text{NO}_x$), particulate matter ($\text{PM}$), ground-level ozone ($\text{O}_3$), and lead ($\text{Pb}$).

Which criteria pollutants are primary pollutants, and which one is formed as a secondary pollutant?

Carbon monoxide, sulfur dioxide, nitrogen oxides, and lead are emitted primarily as primary pollutants; ground-level ozone is formed as a secondary pollutant.

What is tropospheric ozone, and what problems does it cause?

Tropospheric ozone is a secondary photochemical oxidant that irritates the eyes and respiratory system, damages sensitive lung tissue, and reduces agricultural crop yields.

Which precursor air pollutants are chemically necessary to produce tropospheric ozone?

Volatile Organic Compounds (VOCs) and Nitrogen Oxides ($\text{NO}_x$), which react in the presence of sunlight.

How does stratospheric ozone differ fundamentally from tropospheric ozone?

Stratospheric ozone is beneficial because it shields Earth from harmful solar ultraviolet radiation, whereas tropospheric ozone is a harmful pollutant and respiratory irritant at ground level.

What ecosystem service is provided by the ozone layer in the stratosphere?

It absorbs harmful ultraviolet (UV) radiation from sunlight, preventing damage to DNA, skin cancers, cataracts, and crop degradation.

What chemical compounds caused the depletion of the stratospheric ozone layer?

Synthetic chlorofluorocarbons (CFCs) and other halocarbons, which release chlorine atoms that catalytically destroy ozone molecules.

What is the Montreal Protocol and why was it enacted?

An international environmental treaty signed in $1987$ to protect the stratospheric ozone layer by phasing out the production and use of ozone-depleting substances, notably CFCs.

What is smog and what are its two main contributors?

A polluted atmospheric haze, with its primary contributors being photochemical oxidants (mainly tropospheric ozone) and particulate matter.

What are hazardous air pollutants (HAPs)?

Toxic air pollutants that are known or suspected to cause cancer, birth defects, reproductive harm, or severe ecological damage.

Why was airborne mercury specifically regulated under the Clean Air Act?

Because it is a dangerous neurotoxin that deposits into aquatic ecosystems and bioaccumulates/biomagnifies in fish consumed by humans.

What is the number one source of indoor air pollution in the United States?

Cigarette smoke.

How do indoor air quality concerns differ between developing and developed countries?

In developing nations, the main risk is indoor smoke from poorly ventilated burning of biomass and coal for cooking and heating; in developed nations, the main risks are chemical off-gassing (VOCs), radon, mold, and tobacco smoke in sealed buildings.

Why is unpolluted rainfall naturally slightly acidic?

Because atmospheric carbon dioxide naturally dissolves into atmospheric moisture to form weak carbonic acid ($\text{H}_2\text{CO}_3$).

How is anthropogenic acid precipitation formed?

Emissions of sulfur dioxide ($\text{SO}_2$) and nitrogen oxides ($\text{NO}_x$) react with water vapor, oxygen, and oxidants in the atmosphere to form sulfuric acid ($\text{H}_2\text{SO}_4$) and nitric acid ($\text{HNO}_3$).

How did the Clean Air Act reduce acid precipitation in North America?

By establishing emissions caps and market-based cap-and-trade allowances targeting sulfur dioxide ($\text{SO}_2$) and nitrogen oxide ($\text{NO}_x$) releases from coal-fired power plants.

What is the largest source of criteria air pollutants in the United States?

Transportation (motor vehicles).

What does this graph illustrate regarding the effect of the 1990 Clean Air Act Amendments (CAAA90) on criteria pollutant emissions?

It shows that emissions of volatile organic compounds, nitrogen oxides, sulfur dioxide, and fine particles were drastically reduced compared to projected emissions without CAAA90.

Why are fine particulate matter particles ($\text{PM}_{2.5}$) specifically regulated?

Because when inhaled, these microscopic particles bypass upper respiratory filters and penetrate deep into the lungs, where they damage lung tissue and can enter the bloodstream.

What is an urban heat island, and during what time of day is the temperature elevation highest?

An urban area that is warmer than surrounding rural countrysides due to heat absorption by concrete and asphalt; the temperature difference is highest in the nighttime.

What is a dust dome over an urban environment?

A concentrated layer of pollutants and particulate matter trapped over a city by stable, slow-moving air masses and urban heat currents.

What is a temperature inversion, and why is it dangerous for air quality?

An atmospheric condition where a warm layer of air caps a cooler layer near the surface, preventing vertical air mixing and trapping dangerous concentrations of pollutants close to the ground.

What is considered the most effective method for air pollution control?

Pollution prevention (reducing or eliminating pollutant generation at the source).

What are Earth's major freshwater compartments?

Glaciers and ice caps (holding the majority of freshwater), groundwater aquifers, and surface water (lakes, reservoirs, rivers, and wetlands).

How is groundwater naturally replenished in the hydrologic cycle?

Through infiltration and percolation of precipitation and surface water downward through porous soil and rock into aquifer recharge zones.

What two major human factors have drastically reduced groundwater levels?

Excessive groundwater extraction for agricultural irrigation and extensive paving/urbanization that prevents natural surface infiltration.

What are the major consequences of groundwater depletion?

Falling water tables, dry wells, reduced streamflow, land subsidence (sinkholes and compaction), and saltwater intrusion into coastal freshwater aquifers.

Why are wetlands ecologically important for groundwater systems?

Wetlands retain and filter surface runoff, allowing water to slowly infiltrate the ground to recharge underlying aquifers.

What is the difference between water withdrawal and water consumption?

Water withdrawal is the total volume of water diverted or removed from a water source, whereas water consumption is the fraction of withdrawn water lost to evaporation, absorption, or product incorporation that is not returned directly to its source.

What are the three main human uses of freshwater, and which sector consumes the largest share globally?

Agriculture, industry, and domestic/municipal use; agriculture consumes the largest share of freshwater worldwide.

Why is traditional flood irrigation inefficient, and what are more water-efficient alternatives?

Flood irrigation loses nearly half of applied water to evaporation and runoff; drip irrigation and low-energy precision application (LEPA) sprinklers deliver water directly to crop roots with minimal loss.

What is 'virtual water'?

The indirect volume of freshwater embedded or consumed during the entire manufacturing, agricultural, or service supply chain of a product.

What is a major industrial use of freshwater?

Cooling systems for thermoelectric power plants and industrial processing facilities.

Which domestic activity typically consumes the most indoor water in a household?

Toilet flushing.

How does national wealth typically influence water use patterns?

As countries become wealthier, per capita water consumption increases due to higher meat consumption, greater industrial output, and higher adoption of water-intensive household appliances and landscaping.

What are the primary benefits and environmental/human costs of building large dams?

Benefits include hydroelectric power generation, flood control, and reliable water storage; costs include community displacement, river ecosystem fragmentation, sediment buildup, and reservoir evaporation.

What is the difference between point source and nonpoint source water pollution?

Point source water pollution discharges from a specific, identifiable outlet (such as a factory discharge pipe), while nonpoint source pollution comes from broad, diffuse runoff (such as agricultural fertilizer or urban street runoff).

Why is dissolved oxygen (DO) measured in water bodies, and what does low DO indicate?

DO indicates aquatic ecosystem health; low dissolved oxygen indicates heavy organic pollution, which consumes oxygen during decomposition and causes stress or death in aerobic aquatic organisms.

What is the ecological difference between oligotrophic and eutrophic water bodies?

Oligotrophic waters are nutrient-poor, clear, and high in dissolved oxygen; eutrophic waters are nutrient-rich, murky, and prone to algal blooms that lower dissolved oxygen.

What is the difference between natural eutrophication and cultural eutrophication?

Natural eutrophication is a gradual, natural nutrient enrichment of a water body over centuries; cultural eutrophication is rapid, human-accelerated nutrient enrichment driven by agricultural runoff and sewage.

How does cultural eutrophication result in aquatic hypoxic zones ('dead zones')?

Excess nitrogen and phosphorus fuel massive algal blooms; when the algae die, decomposing aerobic bacteria consume dissolved oxygen, creating hypoxic conditions where fish and other aquatic life cannot survive.

How do rain gardens help reduce nonpoint source water pollution?

Rain gardens capture, slow down, and filter urban stormwater runoff, allowing soil and vegetation to absorb nutrients and contaminants before they reach waterways.

What was the main goal of the Clean Water Act, and what continues to be its greatest challenge?

The goal was to make all surface waters fishable and swimmable by regulating pollutant discharges; it successfully controlled point sources, but nonpoint source runoff (such as agricultural and urban runoff) continues to be the greatest challenge.