Atmospheric issues
Atmosphere
A blanket of air surrounding the lithosphere
• Atmosphere held to Earth’s surface by gravity • Dynamic (changing): currents and circulation cells constantly moving
Importance • Insulator • Equalizes temperature and pressure across earth’s surface by transfer of heat, energy, and moisture • Shield (against meteors, ultraviolet radiation) • Enables travel of sound waves, aircraft
Without the atmosphere: cold, quiet, cratered place
1 500 312 mi
400 Air molecules
300
200 Altitude (km) Air density
62 mi 100 Air pressure 90% in first Mt. Everest 10 mi 10 mi
Atmospheric composition: Permanent Gases
• All invisible • Nitrogen – 78% – Plant life • Oxygen – 20.9% – Living creatures • Argon – 0.9% – Inert
Variable gases • Water vapor •Humidity •Clouds • Precipitation – Varies between 4% to less than 1% •Lower water vapor in drier areas • Carbon dioxide – Absorbs infrared radiation – ~0.04%
2 Atmospheric Profile
• Atmosphere extends to 32,000 km (20,000 mi) from surface • Three criteria to examine atmosphere – Thermal (temperature) – Composition – Function
Thermal layers: Troposphere
– Where we live – contains 90% of the mass of the atmosphere – decrease of mass with altitude – temperature decreases with height – clouds / weather layer
Thermal layers: Stratosphere
– Layer directly above troposphere – Decrease in amount of gases with altitude – Temperatures increase with altitude • Because of ozone layer within stratosphere • Ozone absorbing ultraviolet light
3 Thermal layers: Mesosphere
• Layer above stratosphere • Temperatures dropping with altitude
• Mesopause – altitude where the temperatures stops dropping
Thermal layers: Thermosphere
• Very thin air – little mass • Temperature increases because receiving ultraviolet light • After thermosphere: Exosphere
4 Compositional layers
Heterosphere Gases separated & layered
Homosphere Gases mixed
Functional Layers
Stratosphere Ozone layer
Atmosphere
• Dynamic – constantly moving and changing • Problem with pollution and atmosphere – doesn’t stay within state or country boundaries - wind
5 Wind
• Differences in atmospheric pressure cause wind • Horizontal movement of air (advection) • Wind flows from high towards low pressure areas – Local: land-sea breezes – Global: westerlies
Land-sea breezes
Global winds
• Persistent winds – Trade winds - ~5-25º N & S – Westerlies - ~35-55º N & S – Easterlies - ~55-75º N & S • Important in understanding where pollutants will travel
6 Vertical Temperature Patterns
• Temperature changes as altitude increases • Without changes to anything else, temperature decreases at an average rate • Environmental lapse rate (average) – observed trend in vertical temperature change
Major issues
• Air pollution – Smog/air pollutants –Acid rain – Ozone(ground-level) • Ozone thinning • Climate change • ENSO (El Niño /La Niña) related issues
Environmental Regulation
• EPA founded 1970; combined several smaller agencies into one to regulate pollutants for both the environment and human health – Charged to protect human health and the environment, by writing and enforcing regulations based on laws passed by Congress – Administers the Clean Air Act • Coincided with the first Earth Day
7 Clean Air Act
• 1963 –1st national legislation for air pollution – Provided grants to assist states but preserved state’s rights to set goals • 1970 – amendments set clean air goals, identified critical pollutants – Primary standards protect human health – Secondary standards protect crops, visibility, materials
Bad air
• Original 7 pollutants regulated by Clean Air Act – Sulfur compounds – fossil fuel burning, industry – Nitrogen compounds – fossil fuel & biomass burning – Carbon monoxide – biomass burning, automobiles – Particulate material – biomass burning, smoke – Metals and halogens – industry, manufacturing – Volatile organic compounds (VOCs) - plants – Photochemical oxidants – chemical reactions – Air toxins – industry (hazardous air pollutants)
Sulfur compounds Carbon monoxide
8 What happens to air pollution? • Pollutes air – breathing problems • Pollutes water – consumption issues • Pollutes soil – breathing and consumption – High concentrations of mercury and lead often found near old industrial sites – downwind of industry – Asbestos, diesel also found in soil
How is it cleaned up?
• Improve the filtering of industrial sites, cars, and manufacturing plants to stop airborne pollutants • Change technology so filtering is not necessary • Afterward: wait for airborne particulates to settle, then clean up
Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA) • “Clean up releases or threatened releases of hazardous substances that may endanger public health or the environment” • EPA designate sites that are extremely polluted (hazardous waste) so that special attention is paid to clean them up – may receive governments funds – Will first try to determine Potentially Responsible Party (PRP) to have them clean up site • Could be former site owner, current site owner, person who arranged for disposal of contaminant, person who transported contaminant
9 Clean up
• Sites ranged from old military bases to old paper mill sites • Types of cleanup/response: – Removal – typically short term, remove threat – Remedial – clean up site, monitor, long term • Sites where clean up is remedial is conducted under National Priorities List (NPL)
NPL - Superfund Sites
• Hazard ranking system (HRS) identifies the threat level to public and environment of each sites – Scale is from 0 to 100 – Score of 28.5 gets a site on the NPL list, eligible for cleanup – Site can be proposed, listed, and deleted • Superfund has support of states, tribes and communities
NPL • Approx. 1,280 sites currently on list
10 Regional superfund sites
• In our region, 7,000 hazardous waste sites identified. – Of these, 239 sites have been placed on the National Priorities List and have been or are being cleaned up under EPA's authority.
11