Archive for 'Unit 13-Air Pollution & Climate Change'
So, your text had a section on carbon offsets, but we never discussed it in class. There are many companies out there now marketing carbon offsets to reduce your “carbon footprint.” Terrapass is a popular one. You can offset one year’s worth of air travel (an estimated 8,000 pounds of carbon emitted) for just $50.60 as of 5/5/2011. Your money goes to support wind farms and methane capture projects-that’s how the carbon is “offset.” Some companies will even plant trees to offset carbon produced by your lifestyle.
So, does this approach mitigate (lesson) global climate change or encourage “cheating?” Watch this clever parody of carbon offsetting by a couple of Brits:
*If you want to learn more, visit www.cheatneutral.com
So, what do you think?
*Try www.carbonfootprint.com to for a carbon calculator if you want to assess how much carbon dioxide results from your lifestyle.
I do not understand how nitrogen can produce both primary and secondary pollutants.
Also, how in depth do you think we should know the process of scrubbers?
Good luck studying for the last test!
I still do not understand the difference between mitigation and adaptation. Could someone maybe give me examples to help clarify the difference because the definitions from the book confuse me.
First off, Why would a company put VOCs on wood to put in a house. I know its shinier, but were they thinking, “Oh, lets put propane on this wood so the floor can go up in flames faster if it catches fire. Surely the loss of time of escape won’t be a problem.”?
Second, ventilation is a main relief on indoor pollution, even though it could also possibly allow pesticides from the outside to get inside the house. Or am I just applying smoke to other forms of pollution where it is not needed.
Thanks for the tip, and good luck on the test tomorrow.
Since it was such a busy week with prom and since most of you met your scribe post obligations during the energy project, I did not assign scribes over the last few days. So, here is a collection of links from last year’s class on Global Climate Change for those that missed class:
*Since did not have a scribe for ozone day, I pulled this post by alum Kelly Cox ’10 out of the archives.
Today during the second half of class, we discussed ozone, or O3.
The first thing to recognize when discussing ozone is that there is good ozone, and there is bad ozone. You MUST be able to distinguish between the two of these!
Good ozone (O3) is responsible for absorbing and blocking about 95% of harmful UV radiation from the sun in the stratosphere (NOT the troposphere). Good ozone is what we want to maintain in the stratosphere, obviously. Without it, humans and plants are exposed to UV-A and UV-B, which penetrate through the skin and cause DNA to lose electrons. This leads to tumors called carcinoma and melanoma. Without good ozone, we are also at risk of cataracts, severe sunburn, skin cancer, lower crop yields, and less phytoplankton which the food chain depends on.
Bad ozone is a main component of photochemical smog, and obviously we want to minimize the amount of bad ozone that is released into the atmosphere. Bad ozone irritates the eyes, nose, and lungs, and damages plant’s leaves.
One of the most common misconceptions about ozone is that there is a “hole” in the ozone layer. In reality, the issue at should be referred to as “ozone thinning.” The ozone layer varies in thickness and concentration throughout the stratosphere. Thick is obviously better because it can better protect us from UV radiation. Here is a diagram showing the varying concentrations of ozone in the stratosphere but NOTE: No where is there a “hole” or complete absence of ozone!!!
The “hole” is the largest or the most thinning occurs during the spring months (September-October) in Antarctic.
CFCs (chlorofluorocarbons) were discovered in 1928, and at first they were considered “the dream chemical” because they were useful and versatile, yet they weren’t explosive or dangerous, or so they thought. They were used for coolants in refrigerators, propellants in aerosol cans, and in plastic bubble packaging. But in 1974 research proved a reaction of CFCs in the stratosphere, which was destroying good ozone. When UV light hits CFCs, the chlorine in the atmosphere is free and reacts with O3 causing these series of reactions:
Cl + O3 –> ClO (unstable) + O2 ClO + O –> O2 + Cl….. then this Chlorine continues to react with O3 creating a vicious cycle where good ozone is being removed from the stratosphere. Once this discovery was made, a large movement to remove all CFCs from the market quickly began. Here is a good description of this reaction that takes place in the stratosphere that Mr. Willard sent me (I’m not sure who to credit this??):
The Montreal Protocol has been very successful in eliminating CFCs in most products. Almost every country has signed on to it now, and ozone remediation is working, but slowly.
First, we talked about smog. Term coined by combining smoke + fog to get smog. Here are the two types we learned:
- Sulfur-based Smog: “industrial smog”
- Nitrogen-based Smog: “photochemical smog”
Sulfur-based Smog takes on a gray color. When coal is burned compounds within the coal interact with atmospheric oxygen which then causes iron oxide and sulfur dioxide to be released in the atmosphere. *Sulfur oxides are primary air pollutants. The sulfur dioxide in the air can oxidize, then dissolve into atmospheric water droplets to form sulfuric acid. Sulfuric acid is a secondary air pollutant and a main component of acid rain. Acid rain contributes to deforestation and the corrosion of buildings, statues and paint.
Nitrogen-based Smog takes on a brown color. The combustion of an engine leads to the release of many different chemicals. One compound in particular is NO2. When ultra-violet rays from the sun hit NO2, that is now in the atmosphere because of vehicle emissions, an Oxygen atom breaks away but quickly combines with O2 to form O3 also known as ozone. Ozone is good and bad, it just depends on where it is in the atmosphere. Ozone belongs in the stratosphere where it can protect us from the sun’s harsh rays. When ozone is down in the lithosphere it is considered a pollutant because it traps heat and contributes to thermal inversion.
This diagram basically explains that the combustion of an engine leads to emissions of both regulated and unregulated pollutants. (Click to enlarge image) CO, hydrocarbons, NO, NO2 and particulate matter are all regulated. CO2, H2O and N2 are unregulated. The result of these emissions produce primary and secondary pollutants. Secondary pollutants include: ozone formation, acid rain and photochemical smog.
Posted: April 13th, 2011 under LexyL, Scribe Post, Unit 13-Air Pollution & Climate Change.
Tags: air pollution, atmosphere, carbon, coal, fossil fuels, nitrogen, oil, ozone, warming gases
We had a few folks out visiting schools Friday, so here is the scoop. After reviewing the energy unit tests, I briefly reviewed the structure and composition of the atmosphere. Then, I did a brief into to tropospheric air pollution. The Clean Air Act (originally enacted in 1970) has been one of our most successful environmental laws. This law empowered the EPA to establish the National Ambient Air Quality Standards (NAAQS), for certain air pollutants. There are 6 main pollutants for which the EPA has set standards: NO2, O3, SO2, CO, Lead, and PM (particulate matter or SPM, suspended particulate matter). These are MINIMUM standards for acceptable air quality! Here’s the memory trick I offered the class:
Question: How do you remember the list of air pollutants monitored by the NAAQS developed by the EPA?
PM (particulate matter or spm)
Get it? you would need a noseclip to protect yourself from the NOSCLP air pollutants…haha.
*Here is a wonderful, wonderful, wonderful interactive web site that gives you details on the health effects of each (you should have this on pg. 4 of Chp 17 Study Guide also but check it out): http://hank.baaqmd.gov/cleanairprimer/IIIA3.html
You all are probably more familiar with the Air Quality Index (AQI). The AQI is set by the EPA and is based on primarily on measurements of particulates and ground-level ozone. An AQI value over 100 is considered unhealthy (orange). You are most familiar with this when the weather man gives you a color value for today’s air quality (click here for that scale). Ozone is the biggest concern, since that is a clue photochemical smog is forming. Cities that spend too many days in the upper index ranges can be penalized by the federal government withholding highway improvement funds. Charlotte has had some issues with during our summers lately! You can see North Carolina AQI “forecasts” here.