Reading 19.2 notes

Ozone Layer and Its Importance

• Location: The ozone layer is in the stratosphere, approximately 17-26 kilometers (11-16 miles) above sea level.

• Formation: Ozone is primarily created when oxygen molecules react with ultraviolet (UV) radiation from the sun.

• Function: Acts as a global sunscreen, filtering about 95% of harmful UV radiation, making life on land possible.

• Health Benefits: Protects against sunburn, skin cancers, cataracts, and immune system damage. This layer also prevents harmful ground-level ozone formation from tropospheric oxygen.

• Conservation Priority: Preserving the stratospheric ozone layer is critical for human health and environmental protection.

Air Pollution Overview

Definition of Air Pollution

• The presence of chemicals in the atmosphere at harmful concentrations that can affect organisms, ecosystems, and climate.

• Natural sources: Dust, volcanic eruptions, wildfires, volatile organic compounds from plants.

• Human sources: Primarily from industrial processes and burning fossil fuels.

Types of Air Pollutants

• Primary Pollutants: Emitted directly from natural and human activities (e.g., CO, NO, SO₂).

• Secondary Pollutants: Formed through reactions of primary pollutants, (e.g., ozone, sulfuric acid).

Major Types of Smog

• Industrial Smog: Results from coal burning and includes harmful chemicals like sulfur dioxide and suspended particles.

• Photochemical Smog: Created by sunlight acting on pollutants like VOCs and nitrogen oxides, leading to ground-level ozone.

Atmospheric Brown Clouds

• Extent: Large pollution clouds discovered over parts of Asia affecting areas such as India and China.

• Contents: Composed of dust, smoke, soot, and toxic metals like mercury and lead.

• Health Impact: Linked to over 380,000 deaths annually in China and India; contributes to respiratory illnesses and indirectly affects global weather patterns.

• Effects on Glaciers: Particles from these clouds accelerate melting of Himalayan glaciers, compromising water resources in Asia.

Effects and Pollution Cycle

• Pollutants Reach Remote Areas: Airborne pollutants from Asia can reach North America within days.

• Health Effects: Increases in diseases like asthma, heart attacks, and other respiratory issues.

Major Outdoor Air Pollutants

1. Carbon Oxides: CO (toxic) from vehicles and combustion; CO₂ (greenhouse gas) from fossil fuel combustion.

2. Nitrogen Oxides: NO and NO₂ formed from high-temperature environments; contribute to photochemical smog and acid rain.

3. Sulfur Dioxide: Result of coal combustion; contributes to acid rain formation and respiratory issues.

4. Particulates: Small particles that can remain suspended; cause respiratory issues and degrade air quality.

5. Ozone: Beneficial in the stratosphere; harmful at ground level as a component of photochemical smog.

6. Volatile Organic Compounds (VOCs): Emanate from industrial processes and include potent greenhouse gases like methane.

Health Impacts of Air Pollutants

• Lead: Neurotoxin affecting children's development; can cause variety of disorders including reduced IQ and behavioral issues.

• Ozone: Can lead to respiratory problems and aggravate existing health conditions; reduces agricultural productivity.

• Particulate Matter: Can penetrate deep into the lungs, causing long-term health effects and decreasing life expectancy.

Solutions and Prevention

• Lead Poisoning Prevention: Banning lead in products, testing for lead in children, and removing contaminated sources.

• Control of Air Pollutants: Implementing stricter regulations on industrial emissions and transitioning to cleaner energy sources.

• Public Health Monitoring: Improving air quality monitoring and public education on the effects of pollution.