PDS AP Environmental Science 5th Period 2010-11

On monday, we talked about how the US and others have turned to protecting and saving nearly extinct creatures.  The government has stepped in and created two lists of creatures that are either endangered, something that is at risk to be extinct in all or some of its natural range, and threatened, something that is at risk to become extinct. We have accelerated the extinction rate by 1000-10000 times faster than natures extinction rate would have.  This needs to be changed because wild species are very important for many reasons: utilitarian uses, aesthetic beauty, moral reasons, and ecological reasons.

These creatures are some of the most noticeable endangered or threatened species across the globe.  These creatures are vital parts of their ecosystems and are normally top tier predators that keep the other populations intact and not have them blow out of proportion.

Some ways that we have been trying to prevent these extinctions are treaties, or other pacts like CITES, or Convention on International Trade of Endangered Species.  This prohibits international trade of any endangered or threatened species across international borders. Also The ESA or Endangered Species Act, protects creatures and the critical habitat from being harmed.  These are only two of the many acts and treaties that have been enacted to protect endangered species.

Some of the main reasons that creatures go extinct prematurely are in a nice acronym HIPPO, this is the five highest reasons for premature extinction.  1) Habitat Destruction.  2) Invasive species 3) Human population growth 4)Pollution and 5) Over harvesting/poaching.  This spells HIPPO.

An example of how a species succumbs to HIPPO are sharks all around the world, this video talks about how humans are depleting the sharks in such a short time period.  Shark Alert! species struggles.

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:

Intro to Global Climate Change

Global Climate Change

Evidence and Consequences (of the Earth’s Warming)

Solutions to the Earth’s Warming Problem

*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!!!

NOTE: There are different concentrations of ozone, but there is NO "hole" in the ozone layer, only thinning. Source: http://www.skincancer.org/ozone-and-uv-where-are-we-now.html

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??):

A good description of how O3 is destroyed by CFCs in the stratosphere

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.

Since the Montreal Protocol was started, major steps have been taken to reduce the amount of CFCs in products worldwide. Source: http://www.amstat.org/publications/jse/v17n2/nelson.html

On Monday, we learned primarily about smog, or “smoky fog”, which is the dark, sooty pollution one can typically see over heavily populated industrial areas such as Pittsburgh or Mexico City. There are two main types of smog: “grey” smog and “brown” smog, which are obviously named as such due to their color.

gray smog

Grey smog, or “industrial smog” is caused primarily by  sulfur oxides (SOx) released by the burning of coal and other similar fossil fuels into the air which react with oxygen (O2) in the air forming sulfur trioxide (SO3).

• SOx + O2 –> SO3

The sulfur trioxide then reacts with the water vapor in the atmosphere to form the secondary air pollutant sulfuric acid (H2SO3) which is a major component of acid rain. The rain then condenses and falls, weathering both geological and manmade features.

• SO3 + H2O –> H2SO3

Brown smog is caused by the nitric oxide released by vehicles and other petroleum burners into the atmosphere. When a car’s combustion engine runs, it takes in about 78% atmospheric nitrogen (N2) and 21% atmospheric oxygen (O2), it then reacts the oxygen with the burning gasoline, uses the energy released to turn its wheels, and expels the resulting gases. Some of the gases that are expelled include nitrogen, carbon dioxide, and water vapor and droplets. The U.S. government does not regulate any of those emissions, but legislation is being constructed to regulate the emission of carbon dioxide. Currently, the government does regulate the emission of carbon monoxide (which is toxic), hydrocarbons (unburned fuel), and nitric oxide. Nitric oxide is regulated due to its creation of brown smog. The nitric oxide reacts with the atmospheric oxygen to form nitric dioxide (NO2), a red brown toxic gas that causes eye and respiratory irritation.

• NO + O2 –> NO2

The nitrogen dioxide can then react with sunlight to breakdown, releasing Oxygen atoms (O) which then react with atmospheric oxygen forming ozone (O3).

• NO2 + Sunlight –> NO + O
• O + O2 –> O3

The nitrogen dioxide can also react with water vapor in the air, resulting in nitric acid (HNO3) another component of acid rain.

• NO2 +H2O –> HNO3

So, a vehicle’s emissions of hydrocarbons, carbon oxides, and nitric oxides react with sunlight and oxygen to form the primary components of atmospheric smog: ozone, nitric oxides, organic compounds, carbon dioxide, and water vapor.

• Hydrocarbon + Sunlight + O2 + CO + NOx –> O3 + NOx + Organic Compounds + CO2 + H2O

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?
Answer: “NOSCLP”
NO2
O3
SO2
CO
Lead
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

Image Source

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.

Though biodiesel is still an infant industry, it serves as a reasonable alternative energy source to petroleum. Most cars in the United States have gasoline engines, but Mr. Thompson suggested that a diesel engine transition would benefit the environment in the long run. Of course this would be the case only if biodiesel were used in the engine. Diesel engines squeeze air more tightly than gasoline engines and more energy is involved. Gasoline engines are suitable for smaller equipment, and involve air and spark combustions, and a piston.

Formation of Biodiesel:

Biodiesel is made from natural oils (origin: soy, canola, poultry fat, algae, jatropha) in a chemical refinement process.

Advantages:

• Better lubricant for inside of engine than regular diesel
• Reduces carbon emissions by 78.4%
• Not carcinogenic
• Not flammable
• Not hazardous
• Biodegrades quickly

Disadvantages

• Not yet available in great quantities
• Not cheaper than petroleum
• Doesn’t behave well at cold temperature (begins to form a gel between 30-50°F
• Problems with solvent

According to Mr. Thompson,  if biodiesel were the main fuel source, global warming would have less of an impact on the planet. Nonetheless, there is no proof that more gas mileage is gained from the usage of biodiesel, and it’s shelf life is only six months.

Photo Credit to Mr. Willard

Hydrogen Energy is created by passing Hydrogen through a membrane which separates the protons and electrons. In this process, the electrons are diverted to create electricity and H2O is given off as a byproduct. As a fuel source, Hydrogen is clean, with practically no pollutants released, it is efficient, can be up to 90% efficient if heat is harvested, and is safe, when kept in high pressure environments provides no risks.

Here is a quick video on how the fuel cell works http://video.nationalgeographic.com/video/player/environment/energy-environment/fuel-cells.html

Hydrogen Fuel Cell

Currently, scientists are researching how to harvest Hydrogen from algae. If this process is perfected, Hydrogen fuel cells would be a fully renewable energy source.

http://www.biodieselmagazine.com/articles/4268/harvesting-hydrogen-from-algae

Four Types Of Problems

1. E = Energy- basic unit is joules (J)- P x T

P = Power- basic unit is watts (w) = J/sec- E/T

T = Time- E/P

Example: How much energy (in J) does a 30 w bulb if on for 30 min?

E = P x T = 30 J/sec x 60 sec/min x 30 min = 54,000 J

2.  Heat Transfer:

Q = mc x change in temp.

Q = heat energy in calories         m = mass          c = specific heat of water = always equals 1

English version of this equation is in BTU’s- British Thermal Unit

BTU = lb x 1 btu/lbxF x change in temp.

3. Cost / Price:

Units used x Price/Units = Price = cost or bill

4. Efficiency of Devices:

Input = output/efficiency

example: 60 w = output/ .05 = 3 w to light

Commonly asked Efficiency

• Incandescent bulb = 5%
• CFL = 20-25%
• Coal Plant = 30%
• Nuclear Plant = 25%
• Car Engine = 20-25%
• Photosynthesis 1%

Energy not used for energy is lost to heat.

If you thought the photo by Richard Box of the “leaky” high voltage transmission lines was neat, you can check out more of his photography here.  I thought that was an interesting intro to a subject your book seems to ignore-how the electricity gets from all those different types of power plants to your home:

Power Transmission Infrastructure

Image source (and article on how there are plans to replace our “dumb” grid with a “smart” one): http://newsone.com/nation/associated-press/obama-administration-will-spend-3-4-billion-toward-smart-power-grid/

You need a basic working knowledge of “the grid” if you are going to make sense of some of the free response math questions on the AP exam.  If you missed class, the best makeup lesson I can offer is to go through the web pages of How Power Grids Work at HowStuffWorks.com.

*Someone else has scribe duties for the energy math problems covered in class today, so look for another post soon.

Why use solar energy? Lots of reasons. Unlike burning fossil fuels, solar energy is waste-free and results in zero emissions into the atmosphere. It is also a renewable resource, and can be relied on to last as long as the sun does. Despite the initial costs of solar technologies, the use of solar power saves money in the long run because it depends on the free use of sunlight rather than fluctuating oil prices.

Tons of scientists are working not only on how to create new technologies for solar energy that lower the costs, but also how to boost efficiency of the current technology. This Discovery Channel video features a scientist trying to pinpoint the best possible places to capture the sun’s rays: Solar Prospecting (Source: discoverychannel.com)

There are two main types of solar energy technologies:

1. Photovoltaic (PV)- this converts sunlight directly into an electrical charge
2. Concentrating Solar Thermal (CST)- this uses the heat from the sun to create steam which then turns a turbine and powers a generator

Most of the solar panels used on rooftops are photovoltaic. Here is a simple video showing how solar energy can be used to generate electricity for a home: Solar Powered Home (Source: Youtube)

Something that I found even more interesting about solar energy is that it is not limited to single buildings or small scale areas. It is being used in much larger scale projects, like this one in Spain that generates enough electricity to power over 15,000 homes: Solar Plant in Spain (Source: discoverychannel.com)

Improvements in solar technology are being explored every day. This article goes through the history of solar energy and how it has changed from 1979 to 2010: Solar Improvements Article