Environmental Chemistry - Tropospheric Chemistry and Pathways

These flashcards cover key terms and concepts related to environmental chemistry, focusing on tropospheric chemistry, pollutants, and their effects.

VOCs

Volatile Organic Compounds, which are organic chemicals that have a high vapor pressure at room temperature.

Anthropogenic

Originating from human activity.

Butane

An alkane with four carbon atoms, represented as CH3-CH2-CH2-CH3.

Butadiene

A conjugated diene represented as CH2=CH-CH=CH2.

Benzene

An aromatic hydrocarbon with a chemical structure of C6H6, known for its stability and toxicity.

Biogenic VOCs

Organic compounds emitted by living organisms, especially plants.

Isoprene

A colorless volatile liquid hydrocarbon, often emitted by plants.

Limonene

A cyclic monoterpene found in the peels of citrus fruits, a biogenic VOC.

Terpenes

A large and varied class of organic compounds, produced mainly by plants, that have strong odors.

NOx

A term used to describe nitrogen oxides, primarily nitrogen monoxide (NO) and nitrogen dioxide (NO2).

Photolysis

The decomposition of molecules by photons, typically sunlight.

Ozone formation in the troposphere

Involves photolysis of nitrogen dioxide (NO2) and a reaction with oxygen to produce ozone (O3).

Hydroxyl radical (OH)

The key daily oxidant in the troposphere that reacts with many VOCs.

Nitrate radical (NO3)

The major nighttime oxidant, formed from the reaction of ozone and nitrogen dioxide.

Primary pollutants

Pollutants that are directly emitted into the atmosphere, such as NO and VOCs.

Secondary pollutants

Pollutants that form in the atmosphere as a result of chemical reactions between primary pollutants.

Acidic particulate matter

Particles in the atmosphere that can lower pH and have harmful effects on health and the environment.

Dry deposition

The process by which airborne pollutants settle out of the atmosphere without precipitation.

Wet deposition

The process by which pollutants are removed from the atmosphere by precipitation, such as rain or snow.

Ethane

An alkane with the structure C2H6, used in the OH radical reaction.

Carbon monoxide (CO)

A colorless, odorless gas that is a product of incomplete combustion.

Carbon dioxide (CO2)

A colorless gas produced by burning fossil fuels, which is a by-product in many reactions.

NO2

Nitrogen dioxide, a significant air pollutant and a product of combustion.

Nitric acid (HNO3)

A highly corrosive acid formed from reactions involving nitrate radicals.

Particulate matter

Tiny solid or liquid particles suspended in the air, which can have harmful health effects.

Photosmog

Smog that forms from the reaction of sunlight with pollutants like VOCs and NOx.

Health effects of ozone

Elevated levels of ozone can lead to serious health issues, including respiratory problems.

Combine NOx and VOCs

The combination of these pollutants under sunlight contributes to the creation of ozone.

Ozone layer

A region of Earth's stratosphere that absorbs most of the Sun's harmful ultraviolet radiation.

Combustion engines

Engines that burn fuel to produce power, resulting in the emission of pollutants.

Excited O* atom

A highly reactive oxygen atom produced during the photolysis of ozone.

Chemical pathways

The sequences of reactions through which chemical transformations occur.

Atmospheric science

The study of the atmospheric processes and the interactions between the Earth's atmosphere and its ecosystems.

Troposphere

The lowest layer of Earth's atmosphere, where most weather occurs and pollutants are concentrated.

Reaction mechanisms

Detailed descriptions of the steps involved in a chemical reaction.

Vapor pressure

The pressure exerted by a vapor in thermodynamic equilibrium with its condensed phases at a given temperature.

Natural emissions

Pollutants released into the atmosphere from natural sources, such as biological processes or geological activities.

Urban pollution

Pollution concentrated in urban areas, primarily due to traffic and industrial activities.

Ozone (O3)

A molecule composed of three oxygen atoms, important for its role as a pollutant in the troposphere.

Catalytic processes

Chemical reactions that involve catalysts, substances that increase the rate of reaction without being consumed.

Particulate absorption

The uptake of organic compounds by aerosol particles in the atmosphere.

Photochemical reactions

Reactions that occur in the presence of light, especially from the sun.

Atmospheric reactions

Chemical reactions that occur in the Earth's atmosphere, affecting air quality and climate.

Hydroxyl abstraction

The process by which a hydroxyl radical (OH) removes a hydrogen atom from a molecule.

Hydrocarbons

Organic compounds consisting only of hydrogen and carbon, often emitted by vehicles.

Climate impact

The effects of atmospheric changes, including pollutants, on the Earth’s climate and ecosystems.

Ozone pollution

The accumulation of ozone at ground level, which can harm human health and the environment.

Emission reduction strategies

Practices aimed at decreasing the release of pollutants into the atmosphere.

Air quality standards

Regulations established to protect public health and the environment from harmful air pollutants.