HONR 297Environmental ModelsChapter 3: Air Quality Modeling3.1: Background

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“Air Pollution”What do you think of when you

hear the term “air pollution”?Let’s spend a few minutes to

answer this question …

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What I thought of …Vehicles – car truck, etc., exhaustCigarette smokeSmokestacks – factories, power

plantsChemicals from factories

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Smoke stacksIt is interesting

to note that what we see coming out of a smoke stack may actually be water vapor!

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Smoke stacksFurthermore, for

stacks with no visible output, there may be large amounts of invisible, harmful gases that can affect not only the local area, but also possibly areas hundreds of miles away!

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SmogAnother pollution issues

in large cities is smog.From the EPA:

◦ ‘“Smog” … is the mixing of smoke particles from industrial plumes with fog that produces a yellow-black color near ground level.

◦ ‘Under the right conditions, the smoke and sulfur dioxide produced from the burning of coal can combine with fog to create industrial smog.

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Smog◦ The burning of fossil fuels

like gasoline can create another atmospheric pollution problem known as photochemical smog.

◦ Photochemical smog is a condition that develops when primary pollutants (oxides of nitrogen and volatile organic compounds created from fossil fuel combustion) interact under the influence of sunlight to produce a mixture of hundreds of different and hazardous chemicals known as secondary pollutants.

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Smog◦ ‘Smog is the brownish haze

that pollutes our air, particularly over cities in the summertime.

◦ ‘Smog can make it difficult for some people to breathe and it greatly reduces how far we can see through the air.

◦ ‘Smog is a mixture of pollutants with ground-level ozone being the main culprit.

◦ ‘Increased levels of ground level-ozone are generally harmful to living systems because ozone reacts strongly to destroy or alter many other molecules.’

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Air Pollution Examples – VOC’sThe smell of drying paint, stain,

or varnish.These are examples of volatile

organic compounds (VOC’s) being released into the atmosphere.

VOC’s can live for a long time and cause chains of chemical reactions that can contribute to smog.

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Air Pollution Examples - OdorsOther odors, such as those from

◦Garbage◦Factories◦Manure in a field◦New car smells◦A brand new plastic item (such as a

dehumidifier),◦Chemicals in general – are they

harmful?

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Air Pollution Examples - CigarettesCigarette smoke, which besides

having an annoying smell to many people, poses health risks to those who smoke as well as those nearby.

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Air Pollution Examples - RadonRadon gas is a radioactive gas

produced naturally in the ground.It can seep into houses through

foundations (basement walls) and cause health risks for occupants.

Odorless and colorless, but detectable by means of radon detector kits.

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Air Polution Examples – CFC’sChlorofluorocarbons (CFC’s) are used for

spray can propellants, refrigeration, air conditioning, and fire extinguishers.

Once released into the atmosphere, CFC’s can lead to the reduction of ozone in the upper atmosphere.

This reduces the natural shielding from the sun’s UV radiation that ozone in the upper atmosphere provides.

Increased UV exposure leads to health issues including more skin cancer and cataracts, as well as reduced agricultural production.

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Air Pollution Examples – Acid RainAcid rain is “fallout” of certain pollutants in

the atmosphere as they return to the earth’s surface in rain drops.

Acid rain impacts the chemistry of surface water (lakes, streams, etc.), which can cause some species of fish, as well as other forms of aquatic life to die out.

Acid rain also affects forests, soil, old stone monuments, painted surfaces, etc.

Actual sources of acid rain may be located far from the where the rain falls, for example, across state borders!

EPA – Acid Rain Where You Live

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Air Pollution Examples – NOx

Nitrogen Oxides (NOx) are formed from Nitrogen and oxygen in the air from high temperatures as a result of burning fuels in boilers, furnaces, car engines, etc.

Nitrogen oxides contribute to both smog and acid rain, and are bad for our respiratory systems.

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Air Pollution Examples – CO, CO2

Carbon Monoxide (CO) and Carbon dioxide (CO2) are byproducts of hydrocarbons.

What are hydrocarbons – see next slide!

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HydrocarbonsHydrocarbons are organic

compounds consisting entirely of hydrogen and carbon.

They are currently a primary source of energy for the world.

Examples of hydrocarbons include coal, methane, propane, gasoline, and natural gas.

Back to CO and CO2!

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Air Pollution Examples – CO, CO2

Carbon Monoxide is a highly dangerous gas that combines with hemoglobin in blood and reduces the ability of blood to carry oxygen.

Carbon dioxide is a “greenhouse gas”, which means it holds in heat from the earth’s surface – in the same fashion as the glass in a greenhouse.

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Air Pollution Examples - NatureNaturally occurring materials

in the air such as hydrocarbons from trees and plants, methane from decay or digestion of organic material, pollen and other allergens.

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Bottom Line on Air PollutionWhen we breath air, we are

breathing in chemicals that are essential for life (for us, oxygen) as well as chemicals that are or may be harmful to our health!

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Status of Air Pollution in the US

20th Century:◦First half – the focus was on the industrial

economy, mainly due to two world wars. Besides taller smoke stacks, not much was done

to curb or evaluate the environmental impact of industry on air pollution.

◦Second half – the first Clean Air Act was passed in 1963, with many subsequent amendments, including the Clean Air Act Amendments in 1970, the year the EPA was established! The focus has shifted to cleaning up and

prevention of environmental problems!

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What has been done to address/impact Air Pollution? Attempts to control major air pollution sources,

including power plants and factories. Pollution sources have become more severe

◦ Between 1950 and 1980 the number of passenger cars tripled (current car production data from worldometers.com)

◦ Engines became more efficient, but also cars got heavier, so cars maintained about 15 MPG (how about now?)

Due to satellite monitoring as well as scientific fields including atmospheric chemistry and physics, we have a better understanding of the earth’s atmosphere – see for example AIRNow webpage.

Mathematical models including the release of air pollutants from fixed sources have been constructed – we will focus on fixed sources in this course.

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Fixed Source Facilities Regulatory ProcessFor the US and most countries, here is

the general regulatory process:1. An operator must obtain permit(s) from

environmental regulatory authorities to build and operate a plant that will release pollutants into the atmosphere.

2. A permit application includes a detailed description of the underlying processes and an estimate of the amount and type of pollutant(s) to be released.

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Fixed Source Facilities Regulatory Process3. If what a company proposes falls within

agency guidelines (which are often legislated), a permit will be issued.

This permit will include specified limits on releases, with stipulations such as specified time periods, monitoring requirements, and notification guidelines in the event of an emissions release beyond that allowed.

4. Permits of this type are issued for large smoke stacks, smaller smoke stacks, and individual vents – think of the laboratories on campus, such as those in the Chemistry department – each lab hood may require a permit.

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Fixed Source Facilities Regulatory Process4. (cont.) A large facility such as the

Subaru plant in West Lafayette, IN or the Nestle plant in Anderson, IN may have many individual permits or one all-encompassing permit. Here are the permits for these sites from IDEM: (Subaru) (Nestle)

5. Operating plants must control their processes to keep release levels within those permitted (see our text for some examples).

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Fixed Source Facilities Regulatory Process6. Limits imposed by regulatory agencies

often take into account current ambient levels of air pollution.

◦ More stringent requirements may be imposed on facilities operating in areas with “more polluted” air.

◦ The “bubble concept” may be applied – new sources of pollution in a region must be balanced with improvements in the release of pollutants from other sources.

◦ This leads to situations such as one company paying for another’s pollution controls or “pollution rights trading”.

◦ CNN – What is Carbon Trading?

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Resources Cigarette Smoke

◦ http://www.cdc.gov/tobacco/data_statistics/fact_sheets/health_effects/effects_cig_smoking/ Smog

◦ http://www.epa.gov/apti/course422/ap7b4.html

Acid Rain◦ http://

articles.courant.com/2009-12-23/business/hc-acidrain.artdec23_1_duke-energy-power-plants-clean-air-act

◦ http://www.epa.gov/acidrain/where/index.html Hydrocarbons

◦ http://en.wikipedia.org/wiki/Hydrocarbon Greenhouse Gas

◦ http://en.wikipedia.org/wiki/Greenhouse_gas Clean Air Act

◦ http://www.epa.gov/air/caa/ Cars Produced

◦ http://www.worldometers.info/cars/ AIRNOW web page

◦ http://airnow.gov/index.cfm IDEM Permits

◦ http://permits.air.idem.in.gov/27048f.pdf◦ http://permits.air.idem.in.gov/23798f.pdf

Carbon Trading◦ http://www.youtube.com/watch?v=fBrZBJZY_JM

Charles Hadlock, Mathematical Modeling in the Environment, Section 3.1