Air PollutionChapter 18Chapter 18
South Asia’s South Asia’s Massive Brown CloudMassive Brown Cloud
Asian Brown Cloud-2 miles thickAsian Brown Cloud-2 miles thick CausesCauses Chemical composition- Chemical composition- dust, smoke, ash, dust, smoke, ash,
Areas impacted (India, Bangladesh, and China)Areas impacted (India, Bangladesh, and China) Reduced photosynthesis by about 7%Reduced photosynthesis by about 7% Air pollution connects the world –LAAir pollution connects the world –LA 2 weeks to circle the globe2 weeks to circle the globe Steps taken in China and India to reduce air Steps taken in China and India to reduce air
pollutionpollution coal to natural gas coal to natural gas
Air Pollution in Shanghai, Air Pollution in Shanghai, China, China,
• Intro video• The Asian Brown Cloud
18.1 The Atmosphere 18.1 The Atmosphere Consists of Consists of
Several LayersSeveral Layers Divided into layers based on temperature
changes from differences in absorption of incoming solar energy
Atmosphere varies in Density-higher at sea level than top of mountain Atmospheric pressure -decreases with altitude –
less gas molecules at higher altitudes Influenced by Gravity-pulls gas molecules
towards Earth’s surface
Air Movements in the Troposphere Play a Key Air Movements in the Troposphere Play a Key Role in Earth’s Weather and ClimateRole in Earth’s Weather and Climate
Troposphere Troposphere 75–80% of the earth’s air mass Closest to the earth's surface 0-11 km above sea level Chemical composition of air
Nitrogen 78% Oxygen 21% H20, CO2, trace amounts of others (Ar)
Weather, climate and all life forms exist here Involved in chemical cycling Upper boundary = tropopause As altitude increases, temperature decreases
The Stratosphere Is Our Global The Stratosphere Is Our Global SunscreenSunscreen
StratosphereStratosphere 11-50 km above Earth's surface
Similar composition to the troposphere, with 2 exceptions
Much less water (1/1000) O3, ozone layer
As altitude increases, temperature increases
Air motion is horizontal Airplanes fly here
OZONE OOZONE O3 3 – our global – our global sunscreensunscreen
Keeps 95 + % of UV rays from Earth's surface
Allows humans and other life to exist on Allows humans and other life to exist on earthearth
Helps protect humans from sunburn, Helps protect humans from sunburn, cancer, cataracts and damage to the cancer, cataracts and damage to the immune systemimmune system
MesosphereMesosphere 50-80 km
As altitude increases, temperature decreases
Very little O3
Middle atmosphere – Air thin, pressure low
Need oxygen to live in this region. Air quite cold -90°C (-130°F) near the top of mesosphere
ThermosphereThermosphere Altitude increases, temperature
increases “Hot layer” – oxygen molecules
absorb energy from solar rays warming the air. Very few atoms and molecules in this region.
Intense UV – breaks O2 and N2 bonds
International Space Station is here
Comparison of the lower Comparison of the lower atmosphere with the higher atmosphere with the higher
atmosphereatmosphere Continuous mixingContinuous mixing Constant, uniform Constant, uniform
chemical chemical compositioncomposition
Fairly constant Fairly constant temp over a 24 temp over a 24 hour periodhour period
Still air – slow Still air – slow diffusion of gasesdiffusion of gases
Different Different composition at composition at different heightsdifferent heights
Wide temperature Wide temperature variationsvariations
The Earth’s Atmosphere Is a The Earth’s Atmosphere Is a Dynamic System with Four Dynamic System with Four
LayersLayers
18.2 What are the major 18.2 What are the major outdoor air pollution outdoor air pollution
problems?problems?
Air Pollution Comes from Air Pollution Comes from Natural SourcesNatural Sources
Air pollution: presence of chemicals in atmosphere in concentrations high enough to harm organisms
Natural sources Dust blown by wind Pollutants from wildfires and volcanoes Volatile organics released by plants – mold
and terpenes
Air Pollution Comes from Air Pollution Comes from Human Sources (anthropogenic)Human Sources (anthropogenic)
Human sources: mostly in industrialized and/or urban areas Stationary sources - power and
industrial plants Mobile sources - cars, buses
Air Pollution in the Past: Air Pollution in the Past: The Bad Old DaysThe Bad Old Days
Discovery of fire-may have started air pollution problem
Middle Ages-haze of wood smoke over densely populated urban areas
Industrial Revolution-late 1700’s coal being burned for factories and homes-increase in respiratory diseases
London, England 1850s 1952: yellow fog-lasted 5 days-killed over 4,000 Clean Air Act of 1956
The London Smog of 1952The London Smog of 1952 London naturally has very calm air, London naturally has very calm air,
and regularly experiences thick sea and regularly experiences thick sea fog.fog.
The weather turned unusually cold, The weather turned unusually cold, causing the residents to burn greater causing the residents to burn greater amounts of coal to heat their homes.amounts of coal to heat their homes.
This combined with a temperature This combined with a temperature inversion to create a thick smog of inversion to create a thick smog of sulfur dioxide over the city.sulfur dioxide over the city.
The number of fatalities is unknown, The number of fatalities is unknown, but estimated to be 4,000- 12,000.but estimated to be 4,000- 12,000.
1616
United States 1948: Donora, PA; first U.S. air
pollution disaster-coal burning factories, steel mills, zinc smelter and sulfuric acid trapped in fog
1963: New York City - killed 300 Global problem
Air Pollution HistoryAir Pollution History The Donora Fluoride Fog of 1948The Donora Fluoride Fog of 1948
In late October, the town of Donora In late October, the town of Donora experienced a temperature inversion.experienced a temperature inversion.
The town is located along the The town is located along the Monongahela River south of Pittsburgh, Monongahela River south of Pittsburgh, within a small valley.within a small valley.
The main employer of the town was a US The main employer of the town was a US Steel Zinc smelting plant.Steel Zinc smelting plant.
1818
Donora Fluoride FogDonora Fluoride Fog Emissions of sulfur dioxide, nitrogen Emissions of sulfur dioxide, nitrogen
dioxide, and fluoride from the zinc dioxide, and fluoride from the zinc smelting plant began to accumulate.smelting plant began to accumulate.
The smog became so thick that driving The smog became so thick that driving was impossible.was impossible.
The plant itself did not cease operations The plant itself did not cease operations until 4 days later. until 4 days later.
The smog finally broke up as a The smog finally broke up as a rainstorm entered the area after 5 days.rainstorm entered the area after 5 days.
1919
Donora Fluoride FogDonora Fluoride Fog A total of 20 residents died; About a A total of 20 residents died; About a
third to a half of the town’s entire third to a half of the town’s entire population of 14,000 became population of 14,000 became sickened.sickened.
Donora experienced higher than Donora experienced higher than normal mortality rates for 10 years normal mortality rates for 10 years afterwards.afterwards.
2020
Noon in Donora
Some Pollutants in the Atmosphere Some Pollutants in the Atmosphere Combine to Form Other PollutantsCombine to Form Other Pollutants
Primary pollutants- chemical emitted directly into air
Secondary pollutants- when primary pollutants react with each other to form new harmful chemicals – ozone, PANs, HNO3
Air quality improving in developed countries Much more needs to be done in developing countries
Indoor pollution: big threat to the poor 1 in 6 live in area where air is bad
Sources and Types of Air Pollutants
polyacrylonitrile (PAN)
What Are the Major What Are the Major Outdoor Air Pollutants?Outdoor Air Pollutants?
Carbon oxides Carbon monoxide (CO) – colorless,
odorless, highly toxic-car exhaust, open fires, tobacco smoke
Reduces ability of blood to transport oxygen to body
Carbon dioxide (CO2) colorless, odorless
Sources 93% from carbon cycle, rest from burning fossil fuels, clearing forests/grasslands
Human health and environmental impact-Global Warming
What Are the Major Outdoor Air What Are the Major Outdoor Air
PollutantsPollutants?? Nitrogen oxides (NO, NO2 and N2O) and nitric acid
(HNO3) Sources-car engines and coal burning plants Acid deposition-reacting with water vapor Photochemical smog-sun and traffic Human health and environmental impact
Sulfur dioxide (SO2) and sulfuric acid (H2SO4) Colorless, bad smell Sources – 1/3 from sulfur cycle, 2/3 humans-coal in electrical
plants and industrial plants Human health and environmental impact-Asian Brown cloud
Particulates Suspended particulate matter (SPM)
Fine Ultrafine
Sources-dust, wild fires, sea salt (~62%)cars, tobacco smoke, coal burning (~38%)
Human health and environmental impact Toxic particulates (Pb, PCBs and Cd) can cause Toxic particulates (Pb, PCBs and Cd) can cause
reproductive problems, cancer, reduce visibility and corrode reproductive problems, cancer, reduce visibility and corrode metalsmetals
60,000-70,000 premature deaths/year60,000-70,000 premature deaths/year
What Are the Major Outdoor Air What Are the Major Outdoor Air
PollutantsPollutants??
Small particles less than 10 micrometers in diameter pose the greatest problems, because they can get deep into the lungs, and some may even get into your bloodstreamFine particles (PM2.5) are the main cause of reduced visibility (haze) in parts of the United States, including many of our treasured national parks and wilderness areas.
Ozone (O3) – a secondary pollutant An unstable molecule that readily reacts to shed a single O2 atom Human and environmental impact
Volatile organic compounds (VOCs) Organic compounds that exist as gas in atmosphere
Hydrocarbons such as terpenes (C10H15 emitted by leaves of plants) and methane (CH4)
Sources-mainly plants, wetlands and termites (natural) and human sources like oil wells, landfills, cows
Other VOCs are benzene and vinyl chloride that are used as industrial solvents
Human and environmental impact Leukemia, blood disorders, immune system damage
What Are the Major Outdoor Air PollutantsWhat Are the Major Outdoor Air Pollutants??
Chemical Reactions That Form Major Outdoor Air Pollutants
Detecting Air PollutantsDetecting Air Pollutants Chemical instrumentsChemical instruments
Unmanned aircraftUnmanned aircraft Satellites-Asian Brown CloudSatellites-Asian Brown Cloud
2 miles thick, 1-3 miles above ground, covers much of 2 miles thick, 1-3 miles above ground, covers much of India, Bangladesh and China- satellites tracked its India, Bangladesh and China- satellites tracked its movement- even across the Pacific Ocean to California!movement- even across the Pacific Ocean to California!
Nanotechnology-nanodetectors?Nanotechnology-nanodetectors? Biological indicatorsBiological indicators
Lichens-fungus and algaeLichens-fungus and algae - are always absorbing air as a source of - are always absorbing air as a source of
nourishmentnourishment
Natural Capital: Lichen Species, Vulnerability to Air Pollutants
Old mans beard sickens in the presence of SO2
YellowEvernia
also sickens in SO2
Lichen are sensitive to pollution because they lack root and act like sponges, taking in and retaining everything that is in the air and dissolved in rainwater. As pollutants reach a high level, the chlorophyll in the algal portions breaks down and photosynthesis stops
Lead Is a Highly Toxic Pollutant Does not break down in the environment
Sources-toys, paint, water pipes, red, long-lasting lipsticks
Human health and environmental impact Most vulnerableMost vulnerable – children under 6 and fetuses– children under 6 and fetuses Neurotoxin-about 200 kids die per yearNeurotoxin-about 200 kids die per year
Reduction of lead (Pb) Unleaded gasoline Unleaded paint
Still problems 2007: toys with Pb paint recalled Older buildings- Pb- based paint peeling,
Pb contaminated dust, water pipes/faucets
Global bans on lead in gasoline and paint would be helpful- China just phased on leaded gasoline 5 years ao.
Lead Is a Highly Toxic Pollutant
Burning Coal Produces Industrial Burning Coal Produces Industrial Smog Smog
(gray-air smog)(gray-air smog) Chemical composition = Chemical composition = sulfur dioxide, sulfur dioxide,
suspended droplets of sulfuric acid suspended droplets of sulfuric acid (mostly from coal burning), (mostly from coal burning), suspended solid particles and suspended solid particles and dropletsdroplets
Carbon from coal and oil converted to Carbon from coal and oil converted to CO and COCO and CO22
Unburned carbon ends up as Unburned carbon ends up as particulate matter in air (soot)particulate matter in air (soot)
Reduction of this smog in urban Reduction of this smog in urban cities of the United States cities of the United States
China and SmogChina and Smog Each year 358,000 Chinese die from
air pollution (some estimate as many as 750,000 including indoor air pollution)
Relies heavily on coal burning 16 of world’s 20 most polluted
cities are in China 62% of the cities suffer from
industrial smog
How Pollutants Are Formed from Burning Coal and Oil, Leading to
Industrial Smog
Sunlight Plus Cars Equal Sunlight Plus Cars Equal Photochemical Smog – Photochemical Smog – brown air smogbrown air smog
Requires sunlight and carsRequires sunlight and cars Morning traffic releases NOx and VOCs in the airMorning traffic releases NOx and VOCs in the air UV radiation produces a series of reactions that UV radiation produces a series of reactions that
form as many as 100 different compounds such form as many as 100 different compounds such as peroxyacyl nitrates (PANs) and aldehydes.as peroxyacyl nitrates (PANs) and aldehydes.
Ozone is the most Ozone is the most abundant. abundant. In sunlight, NO2
dissociates into O and NO. The O reacts with O2 to produce ozone
Levels off pollutants peak around noon and drop Levels off pollutants peak around noon and drop during the late afternoon, then starts again the during the late afternoon, then starts again the next morning. But NO drops as the sun gets next morning. But NO drops as the sun gets higher as secondary pollutants form.higher as secondary pollutants form.
PANsPANs Peroxyacetyl nitrate causes eye irritations at very low
concentrations of only a few parts per billion. It also irritates the respiratory system. It It may cause emphysema, impaired breathing, acute pulmonary edema or lung lesions following inhalation exposure. People with heart and lung disease, children and the elderly are the most susceptible to air pollutants, including PAN.
PAN inhibits the primary process of photosynthesis in various types of plants, which can stop or reduce their growth. Pan is more toxic to plants than ozone. Affected plants exhibit discolored leaves and leaves can fall off, which further reduces photosynthesis. The plant's ability to store food, grow and reproduce is reduced, and the plants also become more vulnerable to attacks by pests and diseases.
Present in most cities – irritates eyes and respiratory tracts. The heat island effect makes the reactions worse.
Top Related