APES Unit 7: Atmospheric Pollution

Six Criteria Pollutants

• SO2 (Sulfur Dioxide)

• NOx (Nitrogen Oxides → NO & NO2)

• CO (Carbon Monoxide)

• PM (Particulate Matter)

• O3 (Ozone —> tropospheric)

• Pb (Lead)

SO2 (Sulfur Dioxide)

• Coal combustion (electricity)

• Respiratory irritant

• Smog

• Acid precipitation

NOx (Nitrogen Oxides)

• All fossil fuel combustion (especially gas)

• O3

• Photochem smog

• Acid precipitation

CO (Carbon Monoxide)

• Incomplete combustion

• O3

• Lethal to humans

PM (Particulate Matter)

• Fossil fuels

• Biomass combustion

• Respiratory irritant

• Smog

O3 (Ozone)

• Photochemical oxidation of NO2

• Respiratory irritant

• Smog

• Plant damage

Pb (Lead)

• Metal plants

• Waste incineration

• Neurotoxicant

Smog

A mixture of air pollutants, especially smoke and fog, which reduces visibility and harms health

CO2

• Not one of 6 criteria pollutants in Clean Air Act

• Does not directly lower air quality from a human health standpoint

• Not toxic to organisms to breathe

• Not damaging to lungs/eyes

• Does not lead to smog/decreased visibility

• A greenhouse gas → leads to earth warming and environmental & human health consequences

Nitrogen Oxides

• NO, NO2, NOx

• Motor vehicle and fossil fuel combustion

• Natural- forest fires, lightning, soil microbes

• Respiratory irritant, acid rain, smog

Ground-level Ozone

• O3

• Not good in the troposphere, but good in stratosphere

• Respiratory irritant- asthma, bronchitis, emphysema

• Damage to plants

• Greenhouse gas

• NOx and VOCs (volatile organic compounds) react in the presence of sunlight → creates ozone at a lower location in the atmosphere

• Not a natural process → human driven

“Good” Ozone

• O2 split by sunlight and free oxygen binds to make O3

• Ozone in stratosphere is good, but can be destroyed

Sulfur Dioxide

• SO2

• COmbustion of coal and oil

• Volcanoes and forest fires

• Respiratory irritant, affects plants

Carbon Monoxide

• CO

• Formed from incomplete combustion of most matter

• Vehicle exhaust

• Dangerous indoors with poor ventilation

Lead

• Paint in older buildings

• Underground pipes- Flint Michigan

• Toxic to the central nervous system of living organisms

Particulate Matter

• PM

• Solid or liquid particles suspended in air aka particulates

• Combustion of fossil fuels and biomass

• Diesel worse than gas

• Can block sunlight and prevent photosynthesis

PM2.5

• Greatest health concern

• Lodge deep into respiratory tract

• Usually more toxic

• Particles from combustion (especially vehicles) smaller dust particles

• More likely to travel deep into lungs due to smaller size

• Associated with chronic bronchitis and increased risk of lung cancer

PM10

• Health concern

• Too small to be filtered

• Particles or droplets like dust, pollen, ash, or mold

• Too small to be filtered out by nose hairs and trachea can irritate respiratory tract & cause inflammation

Other major pollutants

• Volatile Organic Compounds (VOCs)

• Mercury- combustion

• Carbon dioxide

Primary Pollutants

• Pollutants coming directly from a source like a smoke stack or an exhaust pipe

• Emitted directly from sources such as vehicles, power plants, factories, or natural sources (volcanoes/forest fires)

• NOx, CO, CO2, VOCs, SO2, PM, hydrocarbons

Secondary Pollutants

• Have transformed/changed in the presence of sunlight, water, oxygen, or other compounds

• Occur more during the day (since sunlight often drives formation)

• Tropospheric O3 (Ozone), H2SO4 (Sulfuric acid), sulfate (SO4²-), SO3 (sulfur trioxide), HNO3 (nitric acid), and NO3^- (nitrate)

Natural indoor pollutants

• Radon

• Mold (airborne spores)

• Dust

Radon

• Decay of uranium found in rock and soil

• Radon-222 (most stable isotope; half life- 4 days)

• Naturally occurring radioactive gas

• Moves through soil- into home from basement or cracks in foundation

• Dissolves in groundwater- enters through a well

Radon and smoking

Increase risk of lung cancer by 10 times

Anthropogenic indoor pollution

• Insulation → asbestos

• Lead paint

• VOCs (formaldehyde) → building materials, furniture, upholstery, carpeting

Combustion

• NOx

• SO2

• Carbon Monoxide (CO)

• Particulate Matter (PM)

• Tobacco/vape smoke

Developing countries

• Indoor burning of wood, charcoal, dung, crop residues, coal

• Poor suffer greatest risk

Sick building syndrome

• Indoor air quality in a building

• Causes illness to anyone inside the building

• Common in offices and schools

Delaney Clause of Food, Drug, and Cosmetic Act

• Added to the Food Additives Amendment of 1958

• Provision of the amendment

• If a substance causes cancer in animal or man, it cannot be used as a food additive

Resource Conservation and Recovery Act (RCRA)

• 1976

• Law creating framework for management of waste

• Hazardous and non-hazardous

Montreal Protocol

• International treaty

• To protect the ozone layer

• Stop production of substances that deplete the ozone

• August 1989

Clean Air Act

• 1970

• US Federal Law

• Requires EPA to develop and enforce regulations to protect public from airborne contaminants that can harm human health

Cap and Trade

• Economic approach to controlling pollution

• Incentives to reduce pollutants

• Clean Air Act established Cap and Trade for SO2 in the 90’s

• Effectively reduced acid rain

• Government sets a cap on the maximum level of emissions → only a certain number of allowances

• Then they create permits or allowances under that cap

• If you don’t use them all you can sell yours to another company (if they reach their limit)

• Each year the cap gets smaller

Other clean up policies

• Reduce use of lighter fluid, charcoal barbeques, wood burning fireplaces

• CA- reduce # of bakeries in certain areas

• Restrict automobile use- more public transportation use

• Clean Air Act Amendment → buy and sell allowances on amount of sulfur released & need to release more sulfur - buy more allowance

Reduction of air pollutants- sulfur and nitrogen oxide

• Fluidized bed combustion → coal burned close to calcium carbonate that absorbs sulfur dioxide and makes calcium sulfate

• Lower burn temperatures to reduce NOx → problem is less combustion and increase in PM and CO

• Catalytic converter to reduce NOx → came standard in cars after 1975

Reduction of air pollutants- particulate matter

• Gravitational setting → particles settle to the bottom as exhaust travels in a smokestack

• Typically try to collect and remove PM

• Fabric filters

• Electrostatic precipitator- using charge

• Scrubbers

Reduction of air pollutants- SMOG

• Most are secondary pollutants → must stp primary pollutants first

• Reduce VOCs in urban areas

• Reducing NOx