APES Unit 7

Natural Sources of Air Pollution include:

Dust storms

Volcanoes

Fires

Anthropogenic Sources of Air Pollution include:

Combustion from the burning of fossil fuels in industry and transportation

Leaks from extraction of fossil fuels and other minerals

Primary pollutants

Emitted directly into the air

CO, Pb, SO2, NOX, and suspended particulate matter

Secondary pollutants

Come from reactions of primary pollutants

Tropospheric (Ground Level) Ozone, sulfuric acid, and nitric acid

Point Source Pollution

Can be traced to one, specific location (ex. factory)

Non-point Source Pollution

Cannot be traced to one, specific location, or there are too many sources to be traced back to one (ex. car exhaust)

Point Source Pollution and Human Health - 3 extreme examples

The Bhopal Gas Tragedy

Chernobyl

Deepwater Horizon

Types of Outdoor Air Pollutants (top 6 monitored by the EPA)

Particulate Matter (PM)

Nitrogen Oxides (NOX)

Ground Level (tropospheric) Ozone (O3)

Sulfur Dioxide (SO2)

Carbon Monoxide (CO)

Lead (Pb)

Source and impact of PM

Hair, skin, gas, fire, volcanoes

Variable - respiratory distress to common allergies (depends on size of particle)

Source and impact of NOx

Fossil fuels (especially gas and oil), forest fires, lightning, microbes

Photochemical smog, asthma, inhibits plant growth, eye irritation

Source and impact of O3

Chemical reaction between VOCs, NO_x, and O₂ in the presence of sunlight

Damages plants, respiratory irritation, greenhouse gas

Source and impact of SO2

Combustion of coal and oil, volcanoes, forest fires

Respiratory irritant, damages plant tissues

Source and impact of CO

Incomplete combustion in automobiles

Asphyxiation

Source and impact of Pb

Gasoline (prior to 1996), paint in old homes, pipes (Flint, MI)

Toxic to the central nervous system, affects brain development in children

Stratospheric ozone

GOOD it protects us from too much UV radiation

Tropospheric (ground level) ozone

 BAD is one of the 6 air pollutants regulated by the EPA

How many outdoor pollutants does the EPA monitor?

6

What was the purpose of the Montreal Protocol?

To reduce and reverse depletion of the ozone layer by phasing out CFCs

Where did the Pb in the atmosphere come from?

Paint, Gasoline, and Pipes

What is the only outdoor pollutant monitored by the EPA that is a secondary pollutant?

Ground Level Ozone

How does PM affect the human body?

Common allergies to severe respiratory distress

How is Photochemical Smog made and what does it contain?

NO_x and other pollutants from automobiles/human activity react with sunlight to produce secondary pollutants that make up photochemical smog

Contains tropospheric ozone, NO₂, VOCs, PAN

NO₂ released from car exhaust and enters atmosphere

In the presence of sunlight, NO react with VOCs to create photochemical oxides and form photochemical smog

Peak - mid morning, when NO₂ emissions from vehicles are high

Tropospheric (Ground Level) Ozone

NO2 also reacts with sunlight to produce single O atoms

O atoms react with molecular oxygen (O2) to produce ground level ozone

Peak - mid afternoon, after NO2 has had time to react in the presence of sunlight

What are the environmental factors associated with photochemical smog formation?

Typically found in urban areas due to large numbers of motor vehicles and higher VOC emissions

NO2 is produced early in the day from the morning commute

Ozone peaks in the afternoon and during the summer (it MUST have sunlight to form and the necessary chemical reactions happen faster in warmer conditions)

Environmental Impacts of Photochemical Smog

Blocks sunlight → reduced photosynthesis

O₃ is a respiratory irritant in animals and damages plant stomata (pores that take in CO₂ needed for photosynthesis)

Human Health Impacts of Photochemical Smog

Respiratory irritant

Eye irritant

Increase in asthma, COPD, bronchitis

How Can We Reduce Photochemical Smog?

Decrease the number of vehicles on the road (leads to a decrease in NO2 emissions)

Carpool

Public transit

Bike or walk

Increase the production of electricity from renewable sources

Less NOx emitted if we do not burn fossil fuels

Industrial or Sulfurous Smog

Comes from industrial pollution (factories, mining operations) and fossil fuel combustion

Contains soot, sulfur, CO, and CO2

“Gray Air Smog”

Examples - London, England (Industrial Revolution) and Beijing, China

What ARE Volatile Organic Compounds (VOCs)

Organic compounds wthat evaporate or sublimate quickly at room temperature

Can be natural (terpenes from plants) or anthropogenic (from paints and gasoline, furniture, carpeting)

Almost all scents are the result of them (even candles, perfumes, and room fresheners)

Range from harmless to very toxic (formaldehyde is a VOC)

What causes photochemical smog?

NOx & VOCs react in the presence of sunlight

When is photochemical smog the worst? Why?

In the first half of the day - this is when a lot of NOx and VOCs are released due to commutes.

When is ozone the worst? Why?

Afternoon, when the sun is the strongest.

What activities cause the formation of industrial smog?

Burning of fossil fuels and mining operations.

Can you identify 2-3 things in your house emit VOCs?

Furniture, carpeting, candles, room sprays

What causes a thermal inversion?

Warm fronts

Zones of high pressure

Location - valleys prone to them (cool air sinks)

Typically only occurs over land (the ocean retains heat)

Natural Sources of CO2

Exchange between the ocean and atmosphere

Respiration (from plants and animals)

Decomposition

Volcanic eruptions (account for very little)

Wildfires

Particulate matter can include:

Pollen

Dust from soil

Sea salt

Volcanic ash

Particle pollution includes:

PM10 : inhalable particles, with diameters that are generally 10 micrometers and smaller; and

PM2.5 : fine inhalable particles, with diameters that are generally 2.5 micrometers and smaller

Natural Sources of Indoor Air Pollution

Radon-222

• Naturally occurring radioactive gas

• Produced by the decay of uranium found in rocks and soils

• If you purchase a home with a basement, often a radon test will be performed as part of the home inspection

• #2 leading cause of lung cancer (smoking is #1)

Mold

Dust

Anthropogenic Sources of Indoor Air Pollution

VOCs (ex. formaldehyde) from furniture, carpeting, and building materials

Lead from paint (typically in older homes)

Asbestos (formerly used in insulation)

Combustion

• Remember that many LDCs use biomass as their primary energy source → this releases pollutants

• CO, particulates, tobacco smoke

Potential Impacts of Indoor Air Pollutants

Poor suffer the most (in developing countries biomass is burned directly in the home)

Exposure to Radon gas (which moves into the home via cracks in the walls or foundation) can lead to lung cancer

CO is classified as an asphyxiant - it binds to our red blood cells preventing them from carrying oxygen

Asbestos leads to cancers (mesothelioma)

Indoor, Outdoor, or Both?

Carbon Monoxide

Lead

Radon

Ground Level Ozone

Asbestos

VOCs

Both

Both

Indoor

Outdoor

Indoor

Both

Possible Methods to Reduce Air Pollution

Regulatory Practices (think EPA and Clean Air Act)

Conservation Practices (CAFE)

Pollution Credits

Alternative Fuels and Energy Sources

Vapor Recovery Nozzles

Found on gas pumps

Prevent fumes (VOCs) from escaping into the atmosphere when fueling a vehicle

In newer cars, they have a vapor recovery system built in

Catalytic Converters

Device on internal combustion engines (automobiles)

Converts pollutants in exhaust fumes into less harmful molecule

Wet and Dry Scrubbers

Air pollution control devices that remove gases (NOx, SOx, VOCs - dry) OR gases and particulates (NOx, SOx, VOCs, PM - wet) from industrial exhaust streams

Sometimes used at coal burning power plants

Electrostatic Precipitators (ESP)

Filtration device that removes fine particles like dust and smoke (PM) from an exhaust gas stream before it is released into the environment

“Dirty gas” passes through a negatively charged electrode - it picks up a negative charge

A second electrode is positively charged, negatively charged particles stick to it

Clean gas can then be discharged, collected particles can be disposed in landfills periodically

What are 2 pieces of technology that can limit air pollution in industrial settings?

Scrubbers and ESP

What 2 pieces of technology could limit air pollution in terms of transportation?

Catalytic Converters and Vapor Recovery Systems

What areas of the United States is most affected by air pollution related deaths?

Eastern

Dry Deposition

2-3 days from emission - close places affected more

Aerosol particles

Gasses

Wet Deposition

4-14 days from emission - downwind places affected more

Precipitation (rain, snow, and fog)

Natural Sources of NOx

Lightning Microbes

Natural Sources of SOx

Volcanoes

Anthropogenic Sources of NOx

Motor Vehicles

Coal Power Plants

Anthropogenic Sources of SOx

Coal Power Plants

Effects and Impacts of Acid Deposition

Communities that are downwind from sources of nitrogen oxides and sulfur oxides most at risk

Acidification of soils and bodies of water

Corrosion of human-made structures

What primary pollutants must be emitted in order for acid deposition to occur?

NOx and SOx

What type of acid deposition is acid rain?

Wet

What are some impacts of acid deposition on infrastructure or the environment?

Corrodes human made structures and can acidify waterways

Noise Pollution

Any sound at a high enough level that can potentially cause physiological stress and hearing loss in organisms - it can happen on land and in the sea

Anything above 85 dB can permanently damage hearing

Noise Pollution in Urban Areas may include:

Transportation

Construction

Domestic and industrial activities

Noise Pollution in Residential Areas may include:

Airplanes passing over

Power tools

Loud music

Impacts of Noise Pollution:

Physiological stress (affects body systems)

Masks communication or sounds used for hunting

Cetaceans use echolocation to find their food, sonar from submarines often interferes with this

Damages hearing

Changes migratory routes