Atmosphere as a Resource Types and Sources of Air Pollution

› Major Classes of Air Pollutants› Sources of Outdoor Air Pollutants› Urban Air Pollution

Effects of Air Pollution Controlling Air Pollution in the US

Atmospheric Composition› Nitrogen 78.08%› Oxygen 20.95%› Argon 0.93%› Carbon dioxide

0.04% Ecosystem services

› absorbs UV radiation› Moderates the

climate› Redistributes water

in the hydrologic cycle

Air Pollution› natural events or human activities in high

enough concentrations to be harmful

Two categories› Primary Air PollutantPrimary Air Pollutant

emitted directly into the atmosphere

› Secondary Air PollutantSecondary Air Pollutant formed in the atmosphere when a primary

air pollutant reacts with substances normally found in the atmosphere or with other air pollutants

Particulate Material Nitrogen Oxides Sulfur Oxides Carbon Oxides VOCs Ozone

Solid or liquid particles suspended in air (soil particles, soot, lead, asbestos, and sulfuric acid droplets) › Combustion of wood, manure, coal, oil gasoline.

Agriculture. Road construction.(Black soot from diesel engines more than gasoline powered vehicles)

Natural sources: volcano/forest fires Scatter/absorb sunlight (large forest fire/volcanic

eruption) reduced photosynthesis Dangerous for 2 reasons

› May contain materials with toxic or carcinogenic effects

› Extremely small particles (PM10 and PM2.5) can become lodged in lungs (reduce lung function)

Nitrogen Oxides› Gases produced by the chemical interactions

between atmospheric nitrogen and oxygen at high temperature; cars!

› Problems Greenhouse gas, ozone depleter, contributes to

photochemical smog, leads to acid rain Respiratory irritant, slow plant growth

› Gases produced by the chemical interactions between sulfur and oxygen; industry (chemicals, metal, paper)/power plants (coal!!!!)

› Causes acid precipitation› Respiratory irritant› Slow plant growth

Carbon Oxides› carbon monoxide (CO)

Binds with hemoglobin less oxygen Incomplete combustion

› carbon dioxide (CO2) Greenhouse gas global warming (global

climate change)

Tropospheric Ozone (BAD)› Secondary air pollutant (NOx + VOCs +

sunlight)› Component of photochemical smog› Reduces lung function; asthma; reduce plant

growth; degrade plastics/rubber

Stratospheric Ozone (GOOD; not air pollutant)› Essential component that screens out UV

radiation in the upper atmosphere› Man- made pollutants (ex: CFCs) can destroy it

"Good up high, bad nearby!".

Mercury› Bioaccumulation/biomagnification› Major source: burning coal (electricity)› Harm: brain damage (neurotoxin)

Lead› Gasoline› Paints – eaten by small children› Harm: brain damage (neurotoxin)

Two main sources› Transportation› Industry

Natural –lightening caused fires; volcanoes

Photochemical Smog (ex: Los Angeles below)› Brownish-orange haze formed by chemical reactions

involving sunlight, nitrogen oxide, and VOCs

City surrounded by mountains; in a valley.

NOx + VOCs + sunlight photochemical smog (includes ozone)

NO + VOCs + O2 + uv O3 + PANs› NO2 + H2O 2HNO3 + NO› NO2 + VOCs PANs› NO2 + uv NO + O; O2 + O O3

Hotter = more VOCs

Beijing (left) Mexico City (above) How tied to tourism/economics?

Industrial smog – “gray” smog Photochemical smog – worse in summer

Temperature inversion (thermal inversion)› Cold air with pollutants trapped by warmer air

aboveValleys, coastal

Urban heat island – localized heat buildup (concrete absorbs heat, tall buildings block wind, less vegetation, more industries/cars/air conditioners that produce heat increase thunderstorms; dust domes

Issues: persistent compounds found in areas not using them: worse in colder regions (higher latitudes and higher elevations)› Ex: PCBs: stored in body fat,

example of biomagnification Stockholm Convention on Persistent

Organic Pollutants

Sulfur dioxide and nitrogen dioxide emissions react with water vapor in the atmosphere and form acids that return to the surface as either dry or wet deposition

pH scale: 1 number = 10x change

NORMAL RAIN = pH 5-6

ACID RAIN = BELOW 5

Adirondack Lakes, NY: no fish (reduces species diversity)

Thin-shelled eggs prevent bird reproduction› Because calcium is

unavailable in acidic soil

Forest decline – increases nutrient leaching/directly harms leaves› Ex: Black forest in

Germany (50% is destroyed)

Erodes statues, buildings, etc

Low level exposure› Irritates eyes› Causes inflammation of respiratory tract

Can develop into chronic respiratory diseases

Sulfur Dioxide and Particulate material› Irritate respiratory tract and impair ability

of lungs to exchange gases Nitrogen Dioxides

› Causes airway restriction Carbon monoxide

› Binds with iron in blood hemoglobin› Causes headache, fatigue, drowsiness,

death (at prolonged exposure) Ozone

› Causes burning eyes, coughing, and chest discomfort, asthma

Greater health threat to children than adults› Air pollution can restrict lung development› Children breath more often than

adults Children who live in high ozone (O3)

areas are more likely to develop asthma

Most preventable cause of death› Lung cancer, heart attacks, strokes, other

cancers Increasing in China, Brazil, Pakistan;

decreasing in US, Europe

Smokestacks with electrostatic precipitator (right)

Without Without Electrostatic Electrostatic precipitatorprecipitator

With Electrostatic With Electrostatic precipitatorprecipitator

Smokestacks with scrubbers

Catalytic converters: reduce CO, NOx, and VOCs Drive less

› Mass transit› Bike lanes/wide sidewalks› Carpooling/lanes

Hybrid vehicles

Restrict evaporation ofdry-cleaning fluid

Reduce # of wood burning stoves

EPA sets limits on amount of specific air pollutants permitted

Focuses on 6 pollutants:› lead, particulate

matter, sulfur dioxide, carbon monoxide, nitrogen oxides, and ozone (CO2 added in 2007)

Act has led to decreases!

Clean Air Act Amendment of 1990 focused on reducing

acid rain

Reduce sulfur content in gasoline from its current average of 330 ppm to 30 ppm› Sulfur clogs catalytic converters

Require federal emission standards for all passenger vehicles› Including SUVs, trucks and minivans

Require emission testing for all vehicles› Including diesel

Air quality is deteriorating rapidly in developing countries

Shenyang, China› Residents only see sunlight a few

weeks each year Developing countries have

older cars› Still use leaded gasoline

5 worst cities in world› Beijing, China; Mexico City,

Mexico; Shanghai, China; Tehran, Iran; and Calcutta, India

Worse in developing countries – wood/manure/coal indoors pneumonia/bronchitis

Most common:› Radon, cigarette

smoke, carbon monoxide, nitrogen dioxide, formaldehyde (carpets) pesticides, lead (paint/plumbing), cleaning solvents, ozone (photocopiers), and asbestos

More time inside Better sealed/insulated for energy efficiency More products from plastics and other petroleum-based products

•Most serious indoor air pollutant

•From radioactive decay of uranium in Earth’s crust

•Increase lung cancer risks

• -2nd leading cause

Highly sealed buildings build-up of VOCs and other toxic material (glues, cleaning agents, copy machines), mold/pollen….poor ventilation

Eyes irritated, headaches, nausea, respiratory infections› Lost work time, medical bills

Cap and trade Tax incentives for pollution control Legislative standards for energy

efficiency Increasing research into renewable

energy

Possible solutions: noise barriers next to highways, limit vehicle speed, quieter jet engines, local laws/enforcement for residential power tools, loud radios, etc.

Unit of measurement: decibel (db)

Prolonged exposure damages hearing by hurting hair cells in the cochlea

Increases heart rate, migraines, dizziness, stress

Disrupts animal behavior:

frogs calls difficulty finding a mate

Ozone protects earth from UV radiation (UV-B, UV-C)› Part of the electromagnetic spectrum with wavelengths

just shorter than visible light

O2 + O O3 (catalyzed by UV of sun)

Ozone thinning/hole› First identified in 1985 over

Antarctica Caused by

› human-produced bromine and chlorine containing chemicals

› Ex: CFCs (chlorofluorocarbons): propellants, coolants, foam-blowing agents

› Stable: stay in atmosphere

Thinning over Antarctica requires two conditions: (between Sept. and Nov. – spring)

› Sunlight just returning to polar region› Circumpolar vortex- a mass of cold air that

circulates around the southern polar region Isolates it from the warmer air in the rest of the

planet causes clouds that Cl and Br stick

Polar stratospheric clouds form› Enables Cl and Br to destroy ozone› Cl+O3------------->ClO+O2

› ClO+O------------->O2+Cl

Higher levels of UV-radiation hitting the earth› Eye cataracts› Sunburns, Skin

cancer (right)› Weakened immunity

decrease photosynthesis

damage crops (reduce

crop yields) and forests

Montreal ProtocolMontreal Protocol (1987)› Reduction of CFCs (also a greenhouse gas)

by 50% originally› Started using HCFCs

(Hydrochlorofluorocarbons; weaker ozone depleter;greenhouse gas), phasing out

Phase out of all ozone destroying chemicals is underway globally

ozone layer is recovering; full recovery will not occur until ~ 2050