The atmosphere is essential for life on Earth, but it's extremely thin, comparable to a layer of plastic wrap around a basketball.
Human activities have negatively impacted the atmosphere, primarily through pollution from vehicles and power plants that burn fossil fuels.
Understanding the Atmosphere
Major components of the atmosphere: Nitrogen, Oxygen, Argon, and trace amounts of Neon, Helium, Water, and Carbon Dioxide.
Carbon Dioxide is crucial for understanding climate change and constitutes a small percentage of the atmosphere.
Layers of the Atmosphere
Troposphere
Contains all life forms and is where weather patterns occur.
Most environmental science happens here.
Stratosphere
Home to the ozone layer, which protects us from harmful UV radiation.
Ozone - Good vs. Bad
Tropospheric Ozone:
Bad for health; a pollutant linked to respiratory issues and contributes to photochemical smog.
Stratospheric Ozone:
Essential; protects against UV radiation and acts as Earth's sunscreen.
Most ozone is located high in the stratosphere and absorbs UVC and most UVB radiation.
Risk of Ozone Depletion
CFCs (chlorofluorocarbons) led to ozone depletion by releasing chlorine that attacks ozone molecules, resulting in the ozone hole.
International response: Montreal Protocol (1987) banned CFCs, which helped in ozone recovery.
Air Pollution Overview
Air Pollution is harmful to humans and all organisms; 5-6 million deaths annually due to respiratory issues.
The Environmental Protection Agency (EPA) monitors air quality and focuses on six criteria pollutants:
NOx (Nitrogen Oxides)
SOx (Sulfur Oxides)
Particulate Matter
Lead
Carbon Monoxide
Ozone
Understanding Criteria Pollutants
Oxides (NOx and SOx):
Produced from burning fossil fuels, causing respiratory issues and contributing to acid rain.
Particulate Matter (PM):
Includes smoke, dust, and soot; smaller particles (PM2.5) are more harmful to health.
Lead:
Neurotoxin from industrial sources, persists in the environment, and affects brain development.
Carbon Monoxide:
Colorless and odorless; blocks oxygen transport in the blood, leading to suffocation.
Tropospheric Ozone:
A result of chemical reactions involving NOx, VOCs, and sunlight, contributing to smog.
Legislative Impact on Air Quality
The Clean Air Act dramatically reduced the pollution levels of various pollutants, including carbon monoxide, sulfur dioxide, and NOx since its enactment.
Air quality has improved due to regulations and technology like catalytic converters and scrubbers.
Conclusion
Air pollution negatively affects human and ecological health.
Major sources are human activities, primarily from combustion processes.
Progress has been made in reducing pollution, but ongoing efforts are essential for maintaining air quality and combating climate change, highlighting the role of carbon dioxide as a greenhouse gas.