Environmental Chemistry Terms

Environmental Chemistry Terms

Aerosol

A suspension of particles in a gas. Dust, pollen and soot are all examples of aerosols.

Anthropogenic

Caused by, or from, humans. The burning of fossil fuels is a source of anthropogenic carbon dioxide.

Atmospheric Lifetime

The average time that a molecule spends in the atmosphere before it is removed through chemical reactions or deposition. Lifetimes of atmospheric gases, like vampire relationships, range from minutes to thousands of years. For most greenhouse gases, excluding methane and carbon dioxide, the atmospheric lifetime is equal to the residence time.

Biogenic

Produced by life processes. Examples of biogenic compounds include carbon dioxide released from decomposition and hydrogen sulfide released by wetlands.

Cation Exchange Capacity (CEC)

Describes how often cation swaps occur in the soil. CEC is expressed as centimoles of charge per kilogram of soil (cmolc/kg soil). Talk about a mouthful.

Chapman Reaction Sequence

Ozone is made, ozone is destroyed, ozone is made, ozone is destroyed. This is the ozone cycle.

Chlorofluorocarbons (CFCs)

These chemicals have the dubious honor of helping to widen the hole in the ozone layer and contributing to the big hair of the 1980s. Like the name suggests, they are comprised of chlorine, fluorine, and carbon. Before being banned in the 1990s, they were widely used in everything from refrigerators to hairspray.

Free Radicals

An atom with an unpaired electron. Free radicals differ from ions because they usually don't have a charge.

Global Warming

The increase of mean global temperature. Global warming leads to global weirding, meaning the earth becomes kind of like that one odd, lovable cousin that everyone has.

Global Warming Potential (GWP)

The ability of a gas to trap heat and warm the atmosphere compared to carbon dioxide over a specific time period. CO2 is a typical narcissist and thus all ghg are compared to it. The GWP of CO2 is 1, while methane's GWP is 23.

Greenhouse Effect

The process by which gases in the atmosphere absorb radiation reflected from the Earth's surface. Without the greenhouse effect, the world would have a mean temperature of -18 ° C. That would be unpleasant.

Greenhouse Gas (ghg)

A gas, like methane or water vapor, that traps the radiation that normally would have been sent out into space. These gases contribute to the greenhouse effect.

Hydrocarbons

Hydrocarbons are the ham and cheese of the world of compounds. They are organic compounds made up of hydrogen + carbon. Examples include methane (CH4) and ethane (CH3CH3).

Junge Layer

A layer of aerosols, mostly sulfur, in the stratosphere. It's akin to a giant screen controlling the amount of sunlight reflected and absorbed.

Mole Of Charge (molc)

Moles of charge = oxidation #. One mole of aluminum ions has three moles of charge, because magnesium has a +3 charge.

Nitrous Oxides (NOx)

NOx is the lazy man's way of saying nitrous oxides and includes NO and NO2. These compounds are mainly emitted from motor vehicles and are major contributors to acid deposition. Other misdeeds include the formation of smog and contribution to the greenhouse effect.

Odd Species

This isn't someone that would rather build a compostable toilet using pizza boxes than watch reality TV. An odd species is simply a compound with an odd number of atoms, like O3.

Ozone

The Dr. Jekyll and Mr. Hyde of molecules made up of three oxygen atoms. In the stratosphere, ozone is a benevolent protector of mankind ("be gone UV rays"), while in the troposphere ozone attacks living tissue ("be gone life").

Ozone Layer

A maximum concentration of ozone located in the stratosphere. This layer plays a crucial role in blocking UV radiation. The ozone layer is like a bouncer in a club; it lets in some rays while keeping others out.

Photochemical

And where there is light, there is chemistry. Photochemical reactions are chemical reactions started by the absorption of light energy. The ozone cycle contains photochemical reactions, as does the formation of smog. Another well-known process that utilizes photochemical reactions is photosynthesis.

Photochemical Smog

Smog created by the reactions between ozone, VOCs, nitrous oxide, and hydrocarbons. The nitrogen dioxide formed in these reactions is what gives smog that lovely brown tinge.

Radiative Forcing (RF)

A measurement of how out of whack the earth's energy budget is. Energy In – Energy Out = Radiative Forcing. A positive value means things are heating up, while a negative number means the earth is cooling down. The number should be zero, so if it isn't, it most likely is a result of human activities. Radiative forcing can be used to determine how much humans are messing up the climate.

Residence Time

The average time an individual atom or molecule spends in a reservoir. For most gases (except carbon dioxide and methane) this is equal to the atmospheric lifetime. This term is most often applied to greenhouse gases.

Sea Salt Aerosols (SSA)

Aerosols that come from the sea. These aerosols are released when bubbles burst from waves.

Species

A species in chemistry is not the same as in biology. The easiest way to understand species is to give an example. HCO3- and CO3- are both carbonate species. HgCl+, HgCl3-, HgCl42-, and HgCl2 are all mercury-chloro species.

Stratosphere

The region of the atmosphere that goes from 15 to 50 km. This zone is fairly stable and unmixed.

Troposphere

The region of the atmosphere that goes from 0 to 15 km. Most of the atmosphere is located here. This is an unstable region characterized by a lot of mixing (like an arctic blast or a tossed salad).

Volatile Organic Compound (VOC)

VOCs are a grab bag of not so nice chemicals. Paints, cleaning supplies, furniture, printers, and glue (along with thousands of other products) all emit VOCs. The organic part of their name means they contain carbon. The volatile part stems from their low boiling point, which means they evaporate easily. Many VOCs are known or suspected carcinogens. Examples of VOCs include formaldehyde, toluene, gasoline, and benzene. Chances are if it has a strong scent that kind of hurts your head, it's a VOC.