PDS AP Environmental Science 5th Period 2010-11

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

Yesterday in class we learned about the concept of an Ecological Footprint. We defined an ecological footprint as:

“The environmental impact of a person or population in terms of the cumulative amount of biologically productive land and water required to provide the raw materials needed to be consumed and dispose or recycle the waste.”

Which essentially means how much water and land and person or group of people need to maintain their lifestyle. We divided the parts of a biological footprint up into four categories: Goods and services, housing, food resources, and carbon.

Footprint Components

The goods and services aspect represents the materials, land, waste, and energy required to produce, package, ship, and store the products that a person uses. Housing represents the materials, waste, land, and energy needed to build, maintain, heat and cool, and power a person’s home. Food resources are what’s needed to grow/feed, manufacture, package, transport, and store the food products a person consumes. Finally carbon represents the emissions produced by a person’s burning of fossil fuels such as oil in transportation and production, coal in electricity production, and natural gas in heating and cooking.

We also learned the difference between the terms per capita and population. Population means the total number of a species in a given area, while per capita means the average amount per person in a population.

Finally, we learned that a population’s total environmental impact is dependent upon its number of people, the affluence (wealth) of the population, and the technology the population has. Obviously, the number of people in an area increases its environmental impact as more people consume more resources and produce more waste. The affluence of a population also typically results in a higher environmental impact because it drives up consumption. Technology can either increase or decrease a population’s environmental impact as some technologies (such as coal power plants) can drive up carbon emissions, resource consumption, and waste production, while some (such as hybrid cars) decrease those environmental factors. An equation we learned to calculate the total environmental impact of a population is:

I = P x A x T, with I being the total environmental impact, P being the number of people, A being the affluence, and T being the technology.

I think the most pressing environmental issue right now is the BP oil spill. The flowing oil well has already pumped millions of gallons of oil into the Gulf of Mexico, and if it doesn’t stop, the clean up process could be next to impossible. Obviously, oil flowing into the ocean is never good as it damages wildlife habitats, is potentially fatal to both aquatic and coastal life, and deprives aquatic plants of light and oxygen. Also, the spill has been incredibly detrimental to the fishing and tourism economy in the Gulf area. The spill is considered the largest ecological disaster in American history, and without some serious effort and ingenuity it shows little signs of stopping.