Exam 4 Review - ES 2023 - Fall 2024 (2)

Page 1: Air Pollution Overview

Primary Air Pollutants

• Definition: Released directly from various sources.

  • Mobile Sources: Vehicles.

  • Stationary Sources: Industrial sites, power plants, agriculture, mining.

Secondary Air Pollutants

• Definition: Formed through reactions between primary air pollutants and other chemicals.

  • Examples:

    • Acid rain formed by reactions involving primary pollutants.

    • Ground-level ozone (O3) formed by NOx reacting with O2 in sunlight.

Particulate Matter (PM)

• Definition: Small particles/droplets that can stay aloft in the air.

  • Common in smoke and soot released from burning materials.

  • Health Impacts:

    • Especially particles <2.5 micrometers (μm).

    • Causes respiratory diseases, irritates respiratory lining, may aggravate asthma.

    • Associated with increased mortality risks.

Acid Deposition

• Description: A secondary pollutant formed by SOx and/or NOx emissions.

• Formation: Reacts with oxygen and water to create sulfuric/nitric acids.

• Environmental Impact:

  • Adverse effects on aquatic life (e.g. hatching success in fish and amphibians).

Volatile Organic Compounds (VOCs)

• Definition: Chemicals that evaporate easily and are present in the air.

  • Health Hazards: Can irritate lungs and eyes; many released through fossil fuel combustion or household products.

  • Natural sources include bogs, but most harmful emissions come from anthropogenic activities.

Population Affected by Air Pollution

• General Victims: Air pollution affects everyone, but particularly severe for:

  • Individuals with preexisting respiratory conditions (e.g., asthma).

  • Pets can also experience respiratory issues.

• Developing Countries: Many use open fires for cooking and heating, which significantly pollute indoor air.

Indoor Air Quality Issues

• Growing Concern: Increasing focus among public health scientists.

  • Sources include:

    • Cigarette smoke,

    • VOCs from cleaning products,

    • Cooking fumes,

    • Mold,

    • Dust and dust mites,

    • Radon.

Greenhouse Gas Emissions

• Overview: Human activities linked to the greenhouse gas effect.

  • 400 billion metric tons of CO2 emitted since 1751; accounts for 75% of greenhouse emissions.

Air Quality Regulation

• Clean Air Act: Primary U.S. legislation regulating air quality; established in December 1970 by the EPA.

  • Criteria Pollutants: Standards set for six key pollutants:

    • Carbon monoxide, sulfur dioxide (SO2), nitrogen oxides (NOx), lead, ground-level ozone, and particulate matter.

Environmental Justice

• Definition: Access to a clean and healthy environment as a human right.

• Disparities: Low-income and minority communities often bear the brunt of air pollution, frequently located near hazardous sites such as landfills.

Page 2: Climate Change Impact

CO2 Measurement

• Historical Measurement: Accurate since 1958 through air monitoring stations; older data inferred from ice cores.

  • Seasonal fluctuations in CO2 levels due to plant growth cycles.

  • Trend: Almost exponential increase observed since the mid-1900s.

Impacts of Climate Change

• Freshwater Scarcity: Increased scarcity in certain regions.

• Agricultural Challenges:

  • Declines in productivity due to drought and storms.

  • Increased soil erosion and nutrient loss.

• Insect and Disease Trends:

  • Rise in pest outbreaks.

  • Greater frequency and spread of insect-borne diseases.

• Biodiversity Loss: General decline in species diversity.

• Ocean Impacts:

  • Rising temperatures lead to negative consequences on marine ecosystems due to acidification.

• Increased Risk Factors:

  • Higher likelihood of fires and droughts.

  • Increased severe weather events and flooding in coastal zones.

  • Extreme conditions becoming more common (cold winters vs. extreme heat).

  • Health and property risks from sea-level rise and storms.

Weather vs. Climate

• Weather: Short-term atmospheric conditions.

• Climate: Long-term prevailing weather patterns.

  • Example: Today's temperature vs. seasonal averages.

Definition of Climate Change

• Concept: Alteration in long-term meteorological patterns and statistical averages.

Climate Models

• Purpose: Computer simulations for future climate projections (temperature, CO2 levels).

• Usage: To assess natural vs. anthropogenic contributions to climate change.

• Data Requirements:

  • Proxy Data: Indirect measurements aiding historical climate interpretations (e.g., CO2 from ice core bubbles, historical temperatures inferred from isotopic ratios in ice).