7.4 Atmospheric CO2 and PM

Natural Sources of CO2

Sources that naturally contribute to carbon dioxide in the atmosphere, such as respiration, decomposition, and volcanic eruptions.

Particulate Matter (PM)

Solid or liquid particles suspended in air, also referred to as 'particulates'; includes dust, pollen, ash, and mold.

PM10

Particulate matter that is smaller than 10 micrometers in diameter; can irritate the respiratory tract and is associated with chronic bronchitis.

PM2.5

Particulate matter that is smaller than 2.5 micrometers in diameter; can travel deep into the lungs and is linked to increased risk of lung cancer.

Aerobic Decomposition

The process by which organic matter is broken down by bacteria and decomposers in the presence of oxygen, releasing carbon dioxide.

Anaerobic Decomposition

The breakdown of organic matter in low or oxygen-free conditions, resulting in the release of methane (CH4).

Control Group

In the context of the experiment, the control group consists of the dishes placed at various distances from an active road that is not under construction.

Dependent Variable

The dependent variable in the experiment is the amount of particulate matter (PM) collected on the petri dishes.

VOCs (Volatile Organic Compounds)

Organic chemicals that have a high vapor pressure at room temperature, including terpenes and ethylene emitted from plants.

Natural Photochemical Smog

Smog formed by the reaction of sunlight with pollutants such as VOCs, commonly observed in regions like the Smoky Mountains.

Wildfires

Natural wildfires release large quantities of carbon dioxide (CO2) and particulate matter (PM) into the atmosphere as vegetation burns.

Soil Respiration

A natural source of CO2, soil respiration occurs when microorganisms break down organic matter in the soil, releasing CO2 as a byproduct.

Oceanic Release

Oceans release CO2 into the atmosphere through diffusion; warmer water temperatures increase CO2 emissions.

Natural Dust Events

Dust storms and natural dust events contribute to PM by lifting particles from the ground into the atmosphere.

Volcanic Eruptions

Volcanoes release gases such as CO2, sulfur dioxide, and particulate matter into the atmosphere during eruptions.