OUTDOOR & INDOOR

AIR POLLUTION

Outdoor Air Pollution

Primary PollutantsPrimary Pollutants

Secondary PollutantsSecondary Pollutants

SourcesSourcesNaturalNatural

StationaryStationary

COCO COCO22

SOSO22 NONO NONO22

Most hydrocarbonsMost hydrocarbons

Most suspendedMost suspendedparticlesparticles

SOSO33

HNOHNO33 HH22SOSO44

HH22OO22 OO33 PANsPANs

MostMost andand saltssaltsNONO33––

MobileMobile

SOSO4422 ––

Primary vs. Secondary Pollutants

• Primary- put directly into air from polluting source.

• Secondary- when primary combines with other substances in air and creates something more hazardous (acid rain, smog)

• Sun often provides energy for these rxns.

Major Sources of Primary Pollutants

Stationary Sources• Combustion of fuels for power and heat – Power

Plants• Other burning such as wood & crop burning or

forest fires• Industrial/ commercial processes• Solvents and aerosols

Mobile Sources• Highway: cars, trucks, buses and motorcycles• Off-highway: aircraft, boats, locomotives, farm

equipment, RVs, construction machinery, and lawn mowers

Natural Sources

• Forest fires- ash, particulates, carbon dioxide• Volcanoes- ash, acid mist, hydrogen sulfide• Decaying vegetation- sulfur cmpds• Trees & bushes- Volatile Organic Cmpds (VOC’s) give

Blue Ridge Mtns. their blue hue• Pollen • Spores• Viruses• Bacteria• Dust- from storms in arid regions• Gut bacteria- methane gas

Anthropogenic Sources of Air Pollution

Criteria Air PollutantsEPA uses seven "criteria pollutants" as indicators

of air quality1. Sulfur Dioxide: SO2

2. Nitrogen Dioxide: NO2

3. Carbon monoxide: CO

4. Lead: Pb

5. Particulate Matter: PM10 (PM 2.5)

6. Volatile Organic Compounds: (VOCs)

7. Ozone: ground level O3

Sulfur Dioxide (SO2) • Properties: colorless gas with irritating odor• Effects: produces acid rain (H2SO4), breathing

difficulties, eutrophication due to sulfate formation, lichen and moss are indicators

• Sources: burning high sulfur coal or oil in power plants, smelting or metals, paper manufacture

• Class: sulfur oxides• EPA Standard: 0.3 ppm (annual mean)• 2nd largest cause of air pollution-related health

damage. (1st is smoking)• Sulfate particles reduce visibility in the U.S. as much

as 80%• Reflects sunlight so may have cooling effect

Sulfur Dioxide Emissions

See figure 18.5 on page 400

Nitrogen Dioxide (NO2)• Properties: reddish brown gas, formed as fuel

burned in car, strong oxidizing agent, forms Nitric acid (HNO3) in air

• Effects: acid rain, lung and heart problems, decreased visibility (yellow haze), suppresses plant growth

• Sources: fossil fuels combustion, power plants, forest fires, volcanoes, bacteria in soil, fertilizers

• Class: Nitrogen oxides (NOx) • EPA Standard: 0.053 ppm• Excess nitrogen is causing fertilization &

eutrophication of inland waters & seas

Mobile Source Emissions: Nitrogen Oxides

Carbon Monoxide (CO)• Properties: colorless, odorless, heavier than air,

0.0036% of atmosphere

• Effects: binds tighter to Hemoglobin (Hb) than O2, so organs do not get O2 needed, makes you sleepy, impairs mental functions and visual acuity, even at low levels

• Sources: incomplete combustion of fossil fuels 60 - 95% from auto exhaust

• Class: carbon oxides (CO2, CO)

• EPA Standard: 9 ppm • 1 billion tons enter atmosphere/year

Mobile Source Emissions – CO

Lead (Pb)• Properties: grayish metal• Effects: accumulates in tissue; affects kidneys, liver

and nervous system (children most susceptible); mental retardation; possible carcinogen; 20% of inner city kids have high levels

• Sources: particulates from fuel combustion, smelters, batteries

• Class: toxic or heavy metals• EPA Standard: 1.5 ug/m3

• 2 million tons enter atmosphere/year• Mercury- neurotoxin from coal power plants • Both mercury & lead travel on air currents and fall into

aquatic ecosystems causing bioaccumulation & biomagnification in food webs.

Suspended Particulate Matter (PM10) •Properties: particles suspended in air (<10 um)

•Effects: lung damage, mutagenic, carcinogenic, teratogenic

•Sources: burning coal or diesel, volcanoes, factories, unpaved roads, plowing, lint, pollen, spores, burning fields

•Class: SPM: dust, soot, asbestos, lead, PCBs, dioxins, pesticides

•EPA Standard: 50 ug/m3 (annual mean)• PM2.5 is worse b/c small enuf to be inhaled more deeply• Asbestos fibers & cigarette smoke are most dangerous

respirable particles b/c they are carcinogenic

Mobile Source Emissions: Fine Particulate Matter (PM2.5)

VOCs (Volatile Organic Compounds)• Properties: organic compounds (hydrocarbons) that evaporate

easily, usually aromatic • Effects: eye and respiratory irritants; carcinogenic; liver, CNS,

or kidney damage; damages plants; lowered visibility due to brown haze; global warming

• Sources: vehicles (largest source), evaporation of solvents or fossil fuels, aerosols, paint thinners, dry cleaning, wetlands, rice paddies, bacteria, plants (Figure 18.8)

• Class: HAPs (Hazardous Air Pollutants- cause cancer, birth defects, mutation, neutroxins) – Methane– Benzene– Chlorofluorocarbons (CFCs), etc.

• Concentrations indoors up to 1000x outdoors• 600 million tons of CFCs

Ozone (O3)• Properties: colorless, unpleasant odor, major part

of photochemical smog• Effects: lung irritant, damages plants, rubber,

fabric, eyes • Sources: Created by sunlight acting on NOx and

VOC , photocopiers, cars, industry, gas vapors, chemical solvents, incomplete fuel combustion products

• Class: photochemical oxidants• Good ozone vs. bad ozone- good is in stratosphere

and bad is at ground level (from cars)• Figure 18.10 shows secondary production of urban

smog by photochemical rxns in atmosphere

http://oceanworld.tamu.edu/resources/oceanography-book/Images/ozoneform.gif?action=jump.jump_ozone

Other Air Pollutants• Carbon dioxide- natural source from Carbon dioxide- natural source from

photosynthesis & respiration; human caused photosynthesis & respiration; human caused from fossil fuels & deforestationfrom fossil fuels & deforestation

• CChlorohloroFFluoroluoroCCarbons (CFC’s)- from arbons (CFC’s)- from refrigerants, aerosols, Styrofoamrefrigerants, aerosols, Styrofoam

• Formaldehyde- building materials & Formaldehyde- building materials & household productshousehold products

• Benzene- paintBenzene- paint• Asbestos- car brakes, building materialsAsbestos- car brakes, building materials• Dioxins- pesticidesDioxins- pesticides• Cadmium- smelting, batteries, plastics Cadmium- smelting, batteries, plastics

industryindustry

Formation & Intensity of Pollutant is influenced by…

• Local climate (inversions, air pressure, temperature, humidity)Local climate (inversions, air pressure, temperature, humidity)• Topography (hills and mountains)Topography (hills and mountains)• Population densityPopulation density• Amount of industryAmount of industry• Fuels used by population and industry for heating, Fuels used by population and industry for heating,

manufacturing, transportation, powermanufacturing, transportation, power• Weather: rain, snow,windWeather: rain, snow,wind• Buildings (slow wind speed)Buildings (slow wind speed)• Mass transit usedMass transit used

Pollutants

warmair

cool air

• surface heated by sun• warm air rises (incl. pollutants)• cools off, mixes with air of equal density & disperses

cool air

warm air (inversion layer)

• surface cools rapidly (night)• a layer of warm air overlays surface• polluted surface air rises but cannot disperse remains trapped

Thermal Inversion- occur in valleys

-pollutant effects are intensified when air cannot move upward due to cold upper air layer

...when polluted air is stagnant (weather conditions, geographic location)

Los Angeles, CA

Smog Forms

Solarradiation

Ultraviolet radiation

NONitric oxide

P h o t o c h e m i c a l S m o g

H2OWater

NO2

Nitrogendioxide

Hydrocarbons

O2

Molecularoxygen

HNO3

Nitric acid

PANsPeroxyacyl

nitrates

Aldehydes(e.g., formaldehyde)

O3

Ozone

OAtomicoxygen

Photochemical Smog

Urban Heat Islands

• Cities are generally 3-5ºC warmer than rural areas

• Caused by:– Lack of vegetation to absorb heat– Dark buildings & roads trap heat– Buildings create windbreaks

• Dust Dome- trapping of dirt & particulates over city

INDOOR AIR POLLUTION

What are some sources of indoor air pollution?

1. Cigarette smoke– Deadliest indoor air

pollutant– Contain formaldehyde,

carbon monoxide– Causes lung cancer,

emphysema– Second hand smoke may

be worse due to particulates that come from tip.

What are some sources of indoor air pollution?

2. Mold– Moisture in vents,

carpets– Allergy symptoms,

breathing problems, headache, fatigue

What are some sources of indoor air pollution?

3. Carbon monoxide– Malfunctioning

furnace, gas appliances, cars

– Blood cannot carry oxygen

– Feel sleepy, nausea, dizzy, cause death.

What are some sources of indoor air pollution?

4. Radon– Colorless, odorless,

radioactive gas– Comes from soil under

basements– Long term exposure can

cause lung cancer– Fix cracks in floor or walls

to prevent influx of radon– Install ventilation fan in

basement to blow radon out.

Zone 1 (purple) high levels of radon

Zone 3 (yellow) low levels of radon

What are some sources of indoor air pollution?

5. Asbestos– Roofing, flooring,

insulation, brakes– OK… unless

disturbed or deteriorates

– Can cause asbestosis (scarring of lungs) and mesothelioma (type of lung cancer)

Plaque build up (scarring) in lung w/asbestosis

What are some sources of indoor air pollution?

6. Lead– Old homes, toys,

lead crystal dishes– Causes behavior &

learning problems, slow growth, hearing problems, headaches

What are some sources of indoor air pollution?

7. Formaldehyde– Pressed wood,

paneling, particle board, glue, deodorizers

– Respiratory irritation, fatigue, skin rash, known to cause cancer

What are some sources of indoor air pollution?

8. VOC’s– Paradichlorobenzene-

mothballs, insecticides– PERC- dry cleaned

clothes– Benzene- paints,

cigarettes– Causes respiratory

problems, headaches, loss of coordination, nausea, organ damage, cancer

Effects of Air Pollution on…

1. Human Health

2. Plant Health

3. Acid Deposition

1. Human Health

• Depends on intensity & duration of exposure, age & prior health status

• At-risk groups: young, old, or already suffering from respiratory/cardiovascular disease. Also, more active & outside vs. sedentary inside lifestyle

• Most susceptible- LDC use smoky fires for cooking & heating

Exposure• Time spent in various environments in US and

less-developed countries

How is it introduced to body?

• Inhalation

• Absorption thru skin

• Contamination of food & water

How does air pollution affect people?

• Chronic bronchitis- coughing, trouble breathing

• Asthma- not caused by air pollution, but aggravated by it.

• Emphysema- lungs lose elasticity, hard to breathe

• Lung Cancer- caused by cigarettes, car exhaust, particulates, asbestos, arsenic, radon

How does air pollution affect people? Sick building syndrome-

– Buildings closed up to save energy- no circulation

– Effects of fumes intensified

– Symptoms: headache, eye or throat irritation, cough, itchy skin, dizziness, nausea, fatigue

– Feel better when you get fresh air outside.

– ≥20% of workers must be afflicted to be classified as SBS

2. Plant Health• Two Methods of Damage

– Directly toxic• Irritate cell membranes• First few days- discoloration due to

chlorosis (bleaching) of leaf• Later- necrotic (dead) lesions develop

leading to death– Disruption of plant hormones

• Ethylene from fossil fuels, chemical plants is a major culprit

• Synergistic effects (when combined two are worse than each individually) unpredictable

– White pine seedlings exposed to low levels of O3 & SO2 individually are fine. When combined cause death

– In alfalfa, O3 and SO2 together are less harmful than individually.

• Air pollutant effects on plants are sometimes confused with insect damage or other diseases.

Necrotic lesions on lower surface of potato leaves

Chlorosis and necrosis of white pine needles

Necrosis of watermelon leaf

3. Acid Deposition

Measuring Acid Rain• Normal rain is slightly

acidic and has a pH of about 5.0-5.6

• Any rainfall with a pH value less than 5.0 is defined as acid rain

• As of the year 2000, the most acidic rain falling in the US has a pH of about 4.3.

Two Forms…

• Wet

Refers to acid rain, fog, sleet, cloud vapor and snow.

• Dry

Refers to acidic gases and particles.

Increased Acidity

• Dry deposited gases and particles can also be washed from trees and other surfaces by rainstorms.

• The runoff water adds those acids to the acid rain, making the combination more acidic than the falling rain alone.

Compounds

Two main contributers to acid deposition:• Sulfur Dioxide (SO2)• Nitrogen Oxides (NOx)

– NO- nitric oxide (or nitrogen monoxide)– NO2- nitrogen dioxide– N2O- nitrous oxide

• 66% of all sulfur dioxides and 25% of all nitrogen oxides comes from coal or oil electric power plants. Most nitrogen oxides come from cars

When gas pollutants e.g. sulfur dioxide, nitrogen dioxide dissolve

in rain water, various acids are formed.

CO2 + H2O H2CO3 (carbonic acid)SO2 + H2O H2SO3 (sulfuric acid)NO2 + H2O HNO2 (nitrous acid) +

HNO3 (nitric acid)

Acidic Precipitation

Fossil fuelsPower plants

Industrial emissionsAuto emissions

Primary PollutantsSO2

NO2

Secondary Pollutants

H2SO4 HNO2

sulfuric acid nitric acid

soilsleaching of minerals

vegetationdirect toxicity

indirect health effects

sedimentsleaching aluminum

acidic precipitation

Wind

Transformation tosulfuric acid (H2SO4)and nitric acid (HNO3)

Nitric oxide (NO)

Acid fog

Ocean

Sulfur dioxide (SO2)and NO

Windborne ammonia gasand particles of cultivated soilpartially neutralize acids and

form dry sulfate and nitrate salts

Dry aciddeposition

(sulfur dioxidegas and particles

of sulfate andnitrate salts)

Farm

Lakes indeep soil

high in limestoneare buffered

Lakes in shallowsoil low inlimestonebecomeacidic

Wet acid deposition(droplets of H2SO4 andHNO3 dissolved in rain

and snow)

AcidicAcidicPrecipitationPrecipitation

Fig. 17.10, p. 428BIOL 349

Atmosphere

Effects of Acid Rain• The strength of the effects depend on many

factors– How acidic the water is

– The types of fish, trees, and other living things that rely on the water

– The chemistry and buffering capacity of the soils involved

• limestone & basalt have high buffering capacity• have high ANC (Acid Neutralizing Capacity)

Effects of Acid Rain• Has a variety of effects, including damage to

forests and soils, fish and other living things, materials, and human health.

• Also reduces how far and how clearly we can see through the air, an effect called visibility reduction.

• Effects of acid rain are most clearly seen in the aquatic environments

• Most lakes and streams have a pH between 6 and 8

http://cica.indiana.edu/projects/Biology/movies.html

Buffering Capacity• Acid rain primarily affects sensitive

bodies of water, which are located in watersheds whose soils have a limited “buffering capacity” (places that have granite bedrock or soil for example)

• Lakes and streams become acidic when the water itself and its surrounding soil cannot buffer the acid rain enough to neutralize it.

• In areas where buffering capacity is low, acid rain also releases aluminum from soils into lakes and streams

• aluminum is highly toxic to many species of aquatic organisms.– Can attach to fish gills causing suffocation– Can release from soil particles & enter solutions taken up by

plants causing death

http://home.earthlink.net/~photofish/fish_photos/sw10_thumb.jpg

Effects on Wildlife

• Some birds have left areas- no fish, forests destroyed- less nesting space

• Young of most species are more sensitive to environmental conditions than adults.

• At pH 5, most fish eggs cannot hatch.

• At lower pH levels, some adult fish die.

• Both low pH and increased aluminum levels are directly toxic to fish. – Can also stress fish resulting in low

body weight, small size, less able to compete for food, habitats, reduced reproduction, increased susceptibility to disease

Salmon populations have decreased in Norway since 1950 due to acid rain. Red areas show where populations have declined.

Loons no longer nesting in Adirondack Mtn lakes- too acidic for fish which they eat

Acid Rain and Forests

• Acid rain does not usually kill trees directly.

• Instead, it is more likely to – weaken trees by damaging their leaves– limit the nutrients available to them– expose them to toxic substances slowly

released from the soil.

Acid Rain & Forests

• Trees at higher elevations can be more effected because of increased exposure to acid fog or acid cloud vapor

• As water evaporates from leaf, acid becomes more concentrated, burning the leaf tissue.

• Adirondack Mtns

Effects of Acid Rain

Great Smoky Mountains, NC

Effects on Plant Nutrients• Acidic water dissolves the

nutrients and helpful minerals in the soil and then washes them away before trees and other plants can use them to grow.

• Acid rain also causes the release of substances that are toxic to trees and plants, such as aluminum, into the soil.

Effects on Property

• Many statues, monuments, etc. made from limestone (CaCO3), marble or metal

• Acid rain can dissolve rock or tarnish metal

• Expensive to restore, refurbish, maintain

• Car manufacturers now use acid-resistant paint at a cost of $5.00 per new vehicle