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.