Presentation on theme: "HONR 297 Environmental Models"— Presentation transcript:
1HONR 297 Environmental Models Chapter 3: Air Quality Modeling3.1: Background
2“Air Pollution”What do you think of when you hear the term “air pollution”?Let’s spend a few minutes to answer this question …
3What I thought of … Vehicles – car truck, etc., exhaust Cigarette smokeSmokestacks – factories, power plantsChemicals from factories
4Smoke stacksIt is interesting to note that what we see coming out of a smoke stack may actually be water vapor!
5Smoke 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!
6Smog Another 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.
7SmogThe 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.
8Smog‘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.’
9Air Pollution Examples – VOC’s The 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.
10Air Pollution Examples - Odors Other odors, such as those fromGarbageFactoriesManure in a fieldNew car smellsA brand new plastic item (such as a dehumidifier),Chemicals in general – are they harmful?
11Air Pollution Examples - Cigarettes Cigarette smoke, which besides having an annoying smell to many people, poses health risks to those who smoke as well as those nearby.
12Air Pollution Examples - Radon Radon 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.
13Air Polution Examples – CFC’s Chlorofluorocarbons (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.
14Air Pollution Examples – Acid Rain Acid 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
15Air 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.
16Air Pollution Examples – CO, CO2 Carbon Monoxide (CO) and Carbon dioxide (CO2) are byproducts of hydrocarbons.What are hydrocarbons – see next slide!
17HydrocarbonsHydrocarbons 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!
18Air 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.
19Air Pollution Examples - Nature Naturally occurring materials in the air such as hydrocarbons from trees and plants, methane from decay or digestion of organic material, pollen and other allergens.
20Bottom Line on Air Pollution When 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!
21Status 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!
22What 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 severeBetween 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.
23Fixed Source Facilities Regulatory Process For the US and most countries, here is the general regulatory process:An operator must obtain permit(s) from environmental regulatory authorities to build and operate a plant that will release pollutants into the atmosphere.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.
24Fixed Source Facilities Regulatory Process 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.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.
25Fixed Source Facilities Regulatory Process (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)Operating plants must control their processes to keep release levels within those permitted (see our text for some examples).
26Fixed Source Facilities Regulatory Process 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?
27Resources Cigarette Smoke Smog Acid Rain Hydrocarbons Greenhouse Gas SmogAcid RainHydrocarbonsGreenhouse GasClean Air ActCars ProducedAIRNOW web pageIDEM PermitsCarbon TradingCharles Hadlock, Mathematical Modeling in the Environment, Section 3.1