2 Lecture Objectives By the end of this lesson you will be able to: 1. Name some of the problems and costs associated with air pollution2. List two types of national air quality standards3. Describe six responsibilities of the EPA as they pertain to air pollution standards4. List six principal air pollutants and their health and environmental effects5. Describe the nature and source of acid rain, visibility pollution and toxic air pollutants
3 Air Pollution & Respiratory Health The Problem1990More than 2.4 billion pounds of toxic pollutants released into the atmosphere.199198 areas exceeded recommended levels for carbon monoxide140 million people lived in those areas70 exceeded recommended levels for particulate matter50 exceeded recommended levels for sulfur dioxide
4 Air Pollution & Respiratory Health CostsHealth costs of exposure to outdoor pollutants $40 million upEstimated 50,000 – 120,000 premature deathsAsthmaPeople experience more than 100 million days of restricted activityHealth costs exceed $4 billion~ 4,000 people die of asthma
5 Air Pollution Clean Air Act Passed in 1970 Amended in 1990 Revised Ozone and Particulate Matter Standards
6 Air Pollution Sources of Air Pollution Stationary Sources Factories, power plants, smeltersArea Sources (smaller stationary sources)Dry cleaners, degreasing operationsMobile SourcesCars, buses, planes, trucks, trainsNatural SourcesWindblown dust, volcanic eruptions
7 Air Pollution Clean Air Act Six EPA Responsibilities Setting national ambient air quality standards (NAAQS) for the six principal pollutants.Ensuring the standards are met, or attained.Reducing emissions of sulfur dioxide and nitrogen oxides that cause acid rain.Reducing air pollutants such as particulate matter, sulfur oxides, and nitrogen oxides that cause visibility impairment across large regional areas.
8 Air Pollution Clean Air Act EPA Responsibilities Ensure that sources of toxic pollutants that cause or may cause cancer, other adverse human health problems or adverse environmental effects are well controlled and risks to public health and the environment are substantially reduced.Limiting use of chemicals that damage the stratospheric ozone layer, in order to prevent increased levels of harmful ultraviolet radiation.
9 1997 National Air Quality Types of National Air Quality Standards “Primary Standards”Designed to establish limits to protect public health, including health of “sensitive” populations such as asthmatics, children and elderly“Secondary Standards”Sets limits to protect public welfare, including protection against decreased visibility and damage to animals, crops, vegetation, and buildings
10 Air Pollution Six Principal Pollutants 1. Carbon Monoxide (CO) Colorless, odorless and at high levels a poisonous gas.Formed when carbon fuel is not burned completely.Motor vehicle exhaust accounts for ~60% of all CO emissions nationwide. As much as 95% in cities.
11 Air Pollution Carbon Monoxide (CO) Health Effects Reduces oxygen perfusion to organs and tissuesLow levelsMost serious for people suffering from cardiovascular diseaseHigh levelsPoisonousVisual impairment, reduced work capacity, reduced manual dexterity, poor learning ability and difficulty in performing complex tasks
12 Air Pollution 2. Lead (Pb) Nature and Sources Past – automotive sources were major contributorToday – highest concentrations are found in the vicinity of nonferrous and ferrous smelters and battery manufacturers.Health and Environmental EffectsOccurs mainly through inhalation of air and ingestion of Pb in food, water, soil or dust.
13 Air Pollution 2. Lead (Pb) Health and Environmental Effects Can adversely affect the kidneys, liver, nervous system, may cause neurological impairments, such as seizures, mental retardation and behavioral disordersLow doses associated with damage to the nervous systems of fetuses and young children, resulting in learning deficits and lowered IQ.May be a factor in high blood pressure and subsequent heart disease
14 Air Pollution 3. Nitrogen Dioxide (NO2) Nature and Sources A reddish brown, highly reactive gas that is formed in the ambient air through the oxidation of nitric oxide (NO).Plays a major role in the formation of ozone.Major source of man-made are emissions are high-temperature combustion processes – automobiles and power plants.
15 Air Pollution 3. Nitrogen Dioxide (NO2) Health and Environmental EffectsShort term exposure (less than 3 hrs.)Changes in airway responsiveness and lung function in individuals with pre-existing respiratory illnesses and increases in respiratory illnesses in children.Long term exposure may lead to increased susceptibility to respiratory infection and may cause alternations in the lung.Atmospheric transformation of nitrogen oxides (NOX) can lead to the formation of ozone and nitrogen-bearing particles.
16 Air Pollution 4. Ground-Level Ozone (O3) Nature and Sources Primary constituent of smogIs not emitted directly into the air but rather is formed by the reaction of VOCs (volatile organic compounds) and NO2 in the presence of heat and sunlight.Forms readily in the atmosphere, usually during hot summer weather.
17 Air Pollution 4. Ground Level Ozone (O3) Health and Environmental EffectsShort term (1 – 3 hours) ExposureRepeated exposures make people more susceptible to respiratory infection and aggravate pre-existing respiratory diseases.Decreases lung function and increases respiratory symptoms such as chest pain and cough.Long-term (6 – 8 hours) ExposurePresent the possibility of irreversible changes in the lungs which can lead to premature aging of the lungs and/or chronic respiratory illnesses.
18 Air Pollution 5. Particulate Matter (PM – 10) Nature and Sources Particulate matter (PM) is a general term used for a mixture of solid particles and liquid droplets found in the air.Some can be seen in smoke or soot while others can only be viewed under an electron microscope..Fine Particles (PM – 2.5)Result from fuel combustion from motor vehicles, power generation, industrial facilities, residential fireplaces and wood stoves. Gases such as sulfur oxide, SO2, NO2 and VOC interact with other compounds in the air to form fine particles.Coarse Particles (PM – 10)Result from vehicles traveling on unpaved roads, materials handling, crushing and grinding operations as well as windblown dust.
19 Air Pollution 5. Particulate Matter Health and Environmental Effects Exposure to coarse particles is primarily associated with the aggravation of respiratory conditions such as asthma.Fine particles are more closely associated with such health effects as increased hospital admissions and emergency room visits for heart and lung disease, increased respiratory symptoms and disease, decreased lung function and premature death.Elderly individuals with cardiopulmonary disease and children are at the greatest risk.PM is the major cause of reduced visibility in many parts of the United States.
20 Air Pollution 6. Sulfur Dioxide (SO2) Nature and Sources Gases formed when fuel containing sulfur (mainly coal and oil) is burned and during metal smelting and other industrial processes.Health and Environmental EffectsHigh concentrations can result in temporary breathing impairment for asthmatic children and adults who are active outdoors.Short term exposures to elevated levels may result in reduced lung function accompanied by wheezing, chest tightness and shortness of breath
21 Air Pollution 6. Sulfur Dioxide (SO2) Health and Environmental Effects Longer term exposure of high levels of SO2, in conjunction with high levels of PM, include respiratory illness, alternations in the lungs’ defenses and aggravation of existing cardiovascular disease.Together SO2 and NOX are the major precursors to acidic deposition (acid rain)Sulfur dioxide is also a major precursor to PM 2.5
22 Air Pollution Additional Pollution Concerns Acidic Deposition or Acid RainNature and SourceOccurs when sulfur dioxide and oxides of nitrogen in the atmosphere react with water, oxygen and oxidants to form acidic compounds.Components can be dry (gas or particles) or wet in the form of rain, snow or fog.In U.S. ~64% of annual SO2 emissions and 26% of NOX emissions are produced by electric utility plants that burn fossil fuels.
23 Air Pollution Additional Pollution Concerns Acidic Deposition or Acid RainHealth and Environmental EffectsBefore falling to earth, SO2 and NOX gases and related particulate matter contribute to poor visibility.Acid rain raises the acid levels in soils and water bodies (making the water unsuitable for some fish and other wildlife) and damages trees at some elevations.Also speeds the decay of buildings, statues and sculptures
24 Air Pollution Visibility Visibility impairment occurs as a result of the scattering and adsorption of light by air pollution, including particles and gases.Nature and Sources of the ProblemPrimary emissions (particles) such as dust from roads or elemental carbon (soot) from wood combustion.Secondary emissions (particles) are formed in the atmosphere from primary gaseous emissionsSulfate from sulfur dioxideNitrates from nitrogen oxides
25 Air Pollution Reduced Visibility In eastern U.S. mainly attributable to secondarily formed particlesWestern U.S. largely mainly attributable to primary particlesHumidity can significantly increase the effect of pollution on visibilitySulfates can accumulate water and grow in size reducing visibility more.Annual average relative humidity - in eastern U.S %; in western U.S %Poor summer visibility in the east primarily the result of high sulfate conc. combined with high humidity
26 Air Pollution Toxic Air Pollutants Those pollutants that cause or may cause cancer or other serious health effects such as reproductive effects, birth defects, or adverse environmental and ecological effects.Nature and SourcesEPA addresses 188 toxic air pollutantsExamples include: benzene (found in gasoline), perchloethylene (emitted from dry cleaning facilities), methylene chloride (solvent and plant stripper)Also includes natural sources such as volcanic eruptions and forest fires.Most originate from human-made mobile sources (cars, trucks, etc.) and stationary sources (factories, refineries, power plants)
27 Air Pollution Toxic Air Pollutants Health and Environmental Effects Exposure at sufficient concentrations and duration increases the risk ofcancerdamage to the immune systemneurological damagereduced fertilitydevelopmental problemsrespiratory problems
28 Air Pollution Toxic Air Pollutants Health and Environmental Effects Persistent toxic air pollutants can accumulate in plants and animals magnifying up the food chainA particular concern in aquatic ecosystems where greater magnification can occurIn animalstoxic pollutants disrupt the endocrine systemdecreased fertilitydecreased hatching successdamaged reproductive organsAltered immune systems
29 Air Pollution Stratospheric Ozone Stratosphere - 6 to 30 miles about earth, contains a layer of ozone gas that protects living organisms from harmful ultraviolet radiation (UV-b) from the sunNature and Source of ProblemsDamage has occurred over the past two decadesOzone hole forms over the Antarctic each year and ozone levels fall to 70% below normalIn U.S. ozone levels are ~5% below normal in the summer and 10% in the winter3.4% decrease per decade in average total ozone over the northern hemisphere mid-latitudes since 1979
30 Air Pollution Stratospheric Ozone Nature and Sources of Problem in scientists demonstrated that UV-b levels over most populated areas increased.Increases associated with human activities including use of chlorofluorcarbons (CFCs), halons, carbon tetrachloride and methyl chloroform.These chemicals are found in home air conditioners, foam cushions, etc.
31 Air Pollution Health and Environmental Effects Humans UV-b linked to skin cancer including melanomaCataractsSuppression of the immune systemPlantsSlowed growthSuggestions that marine phytoplankton are already under stress
32 Air Pollution Global Warming and Climate Change Climate is fueled by the sun. Most solar radiation is absorbed by the earth, some is reflected back into space. Atmospheric gases absorb some of the reflected radiation and reflects more still back to the earth where it warms the earth’s surface in a greenhouse effect.Without the greenhouse effect the earth would be much colder and probably covered with ice.
33 Air Pollution Global Warming and Climate Change Nature and Source of ProblemsRecent scientific evidence indicates that the greenhouse effect is increasing.Due to release of certain gases to the atmosphere causing a rise in temperature - Global warmingCarbon dioxide accounts for 85% of greenhouse gases in the USMethane emissions is the second largest contributorOther contributing gases include hydrofluorocarbons (from foam production, dry cleaning, chemical and semiconductor manufacturing), perfluorinated compounds (smelting aluminum); nitrogen oxides (automobile exhaust) contribute to ground level ozone
34 Air Pollution Health and Environmental Effects Greenhouse emission gases could cause a 1.8o to 6.3oF rise in temperature during the next century if levels are not reduced.Small change that could produce extreme weather events including droughts and floods, raising sea levels, increased risk for certain disease by producing new breeding sites. Possible increased insect populations and plant disease.All of these could reduce biological diversity.
35 Air Pollution Conclusion Six Principal Pollutants 1. Carbon monoxide 2. Lead3. Nitrogen dioxide and Nitrogen oxides4. Ozone5. Particulate matter (PM-10) and PM-2.5)6. Sulfur Dioxide and Sulfur oxides
36 Air Pollution Conclusion Other Pollutants Chloroflurocarbons Methane Carbon dioxideHydrofluocarbonsNitrous oxidePerfluorinated carbonsVolatile organic compounds
37 Air Pollution Conclusion The Clean Air Act has been the impetus for improvements in the quality of air in the U.S.New data helps to identify sources of pollution and their properties.Although a lot of progress has been made we must change our lifestyles to reduce pollution