Notes on Atmospheric Pollution, Water and Solid Waste

Outdoor Air Pollutants

Air Pollutants from Burning Coal:

• Carbon Dioxide (CO2): A greenhouse gas that contributes to climate change and global warming through the greenhouse effect. It is emitted during combustion and is a critical concern in discussions of climate policy.

• Sulfur Dioxide (SO2): This gas can react in the atmosphere to form sulfuric acid, resulting in acid rain, which negatively impacts soil, water bodies, and plant life. It is primarily produced from the burning of fossil fuels, especially coal, and petroleum.

• Nitrogen Oxides (NOx): These gases are a precursor to ground-level ozone and contribute to smog formation. They can lead to respiratory problems in humans and have detrimental effects on aquatic ecosystems.

• Particulate Matter: These tiny particles can penetrate deep into the lungs and even enter the bloodstream. They are linked to a variety of health issues, including cardiovascular disease, respiratory diseases, and premature death.

• Volatile Organic Compounds (VOCs): These are organic chemicals that can have adverse environmental and health effects, contributing to ozone formation and causing headaches, dizziness, and asthma exacerbation in humans.

Photochemical Smog Formation:

• Nitrogen oxides and VOCs react in the presence of sunlight to create secondary pollutants such as ground-level ozone, leading to the formation of photochemical smog. This phenomenon is more common in urban areas with high traffic.

Formation of Tropospheric Ozone:

• The chemical reactions involved in ozone formation are as follows:
  NO{2} + sunlight ightarrow NO + O O + O{2} ightarrow O{3} NO + O{3} ightarrow NO{2} + O{2}

• This process highlights the role of sunlight in enhancing smog formation, especially in summer months.

Volatile Organic Compounds (VOCs):

• Definition: Organic chemicals that easily evaporate at room temperature, contributing to air pollution and health hazards.

• Main Sources:

  • Paints: Solvents and paint thinners release VOCs into the air.

  • Gasoline: Evaporation during refueling releases significant amounts of VOCs.

  • Cleaning products: Many cleaning agents contain VOCs that contribute to indoor air pollution.

Smog and Seasonal Variations:

• Higher levels of smog are often observed during warm summer months due to increased sunlight, which intensifies photochemical reactions that lead to the formation of ground-level ozone. This seasonal variation emphasizes the need for stringent air quality regulations during warmer months.

Urban Pollution Sources:

• Major contributions to urban air pollution come from vehicle emissions, industrial activities, and commercial shipping. Efforts to reduce these emissions include promoting public transportation and adhering to stricter vehicle emission standards.

Thermal Inversion:

• Thermal inversions occur when a layer of warm air traps pollutants close to the ground, preventing them from rising and dispersing. This phenomenon can lead to severe air quality problems, particularly in valleys and urban areas.

Particulate Matter (PM)

Natural Sources of PM:

• Volcanoes: Eruptions release ash and gases into the atmosphere.

• Pollen: Naturally occurring substances that can trigger allergies and respiratory problems.

• Rock dust: Eroded rock contributes to dust in the air.

• Dust storms: Winds lift sand and dust into the air, affecting air quality downwind.

• Forest fires (natural causes): Release smoke and particulate matter into the atmosphere.

PM 2.5 vs PM 10:

• PM2.5: Particulate matter smaller than 2.5 micrometers, which can penetrate deeper into the respiratory system, leading to serious health risks, including heart attacks and lung damage.

• PM10: Particles smaller than 10 micrometers that can cause health issues but are less harmful than PM2.5.

Carbon Dioxide (CO2) Sources

Natural Sources:

• Volcanic eruptions: Release CO2 and other gases into the atmosphere.

• Cellular respiration: All aerobic organisms produce CO2 when they metabolize organic matter.

• Ocean-atmosphere gas exchange: Oceans absorb and release CO2, serving as a significant carbon sink, which is crucial for maintaining the carbon cycle.

Indoor Air Pollutants

Significant Indoor Pollutants and Sources:

• Formaldehyde: Found in many household products, including furniture and carpets, and can cause respiratory irritation and other health issues.

• Radon: A colorless, odorless gas that is a decay product of uranium, which can accumulate in homes, especially basements, posing a risk of lung cancer.

• Mercury: Released from fossil fuel combustion as well as during the production of various products including batteries, increasing the risk of neurological damage particularly in children.

• Lead: Found in older paints and pipes; exposure can lead to severe health problems, especially in young children.

• Carbon Monoxide (CO): An odorless gas that results from incomplete combustion of fossil fuels; can cause serious health issues including fatalities due to asphyxiation.

• VOCs: Often found in cleaning products and paints, they can significantly lower indoor air quality.

• Asbestos: A hazardous material formerly used in insulation and construction; exposure can lead to serious respiratory diseases, including mesothelioma.

Health Effects of Lead:

• Lead exposure can cause significant mental and physical developmental delays, behavioral issues, memory loss, and in severe cases, coma or death.

Sick Building Syndrome:

• Symptoms arise when over 20% of occupants report adverse health effects, often attributed to poor indoor air quality and inadequate ventilation.

Reduction of Air Pollutants

Baghouse Filter:

• These systems use fabric bags to filter out and trap particles from industrial exhaust, significantly reducing particulate emissions.

Electrostatic Precipitator:

• Utilizes charged plates to attract and remove particles from exhaust gases, improving air quality from industrial sources.

Scrubbers:

• Wet Scrubber: Absorbs pollutants using liquid solutions, effectively removing gases such as SO2.

• Dry Scrubber: Utilizes dry chemicals to neutralize and remove pollutants before they can enter the atmosphere.

Vapor Recovery Nozzle:

• Designed to capture gasoline vapors during refueling, minimizing volatile organic compound emissions and helping to reduce air pollution.

Catalytic Converter Functions:

• Converts harmful gases:

  • Carbon monoxide is transformed into carbon dioxide.

  • Nitrogen oxides are broken down into nitrogen and oxygen, alleviating smog formation.

  • Unburned hydrocarbons are converted into carbon dioxide and water, reducing overall emissions from vehicles.

Clean Air Act of 1970:

• A significant piece of legislation that mandates nationwide air pollution regulations, promoting cleaner air and public health protection.

NAAQS (National Ambient Air Quality Standards):

• These standards have been established to protect public health and the environment from harmful pollutants, setting limits for various air contaminants.

Acid Rain

Formation from Sulfur and Nitrogen Oxides:

• The reactions that lead to acid rain include:
  SO{2} + H{2}O
  ightarrow H{2}SO{4} (Sulfuric Acid)
  NO{2} + O{2}
  ightarrow NO{3} NO{3} + H{2}O ightarrow HNO{3} (Nitric Acid)

• Acid rain can cause significant harm to aquatic ecosystems, soil quality, and forest health.

Environmental Consequences of Acid Rain:

• Lowers pH levels in water bodies, adversely affecting aquatic life and altering the structure of ecosystems.

• Can lead to leaching of toxic metals from soil into waterways.

Limestone Neutralization:

• Acts as a buffer against acid rain, reacting with acids to increase pH levels, making environments more hospitable for life.

Noise Pollution

Impact on Human Health:

• Noise pollution can cause distractions, increase anxiety levels, disrupt sleep patterns, and lead to hearing loss over time.

Sources of Noise Pollution:

• Construction: Heavy machinery and construction activities generate significant noise.

• Industrial activity: Factories and processing plants can produce continuous noise levels that affect nearby communities.

• Transportation: Vehicles, airplanes, and trains contribute dramatically to urban noise pollution.

Effects on Wildlife:

• Noise pollution can disrupt animal communication, leading to increased predation risks and negatively influencing reproduction and feeding behaviors.

Water and Land Pollution

Point vs Non-Point Sources of Pollution:

• Point Source: Identifiable contributors of pollution, such as smokestacks and wastewater discharge pipes.

• Non-Point Source: Diffused sources, such as agricultural runoff, that are much harder to control effectively.

Human Impact on Coral:

• Increasing Ocean Temperatures: Rise in sea temperatures leads to coral bleaching, where corals expel symbiotic algae, losing their color and essential nutrients.

• Sediment Runoff: Excess sediment can smother coral reefs, reducing light availability needed for photosynthesis and stunting coral growth.

• Destructive Fishing: Techniques like blast fishing damage coral structures and disrupt marine ecosystems.

Oil Spills:

• Oil spills coat marine animals, affecting buoyancy and mobility, leading to long-term ecological damage and population declines.

Dead Zones in Oceans:

• Created by excess nutrients leading to algal blooms, followed by oxygen depletion, which can cause mass fish deaths and biodiversity loss.

Eutrophication Flow Diagram

1. Increase in nitrates and phosphates

2. Algal bloom

3. Algae dies

4. Bacteria decompose dead algae, consuming oxygen

5. Decreased oxygen leads to aquatic organism mortality

Thermal Pollution

Definition: The increase in water temperature disrupting aquatic ecosystems, modifying species distributions and habitat suitability.

Production: Power plants extract river water for cooling and return it at elevated temperatures, which can harm native species and reduce overall biodiversity.

Impact on Water Oxygen Levels: Warmer water holds less dissolved oxygen, exacerbating stress on aquatic life, especially fish and invertebrates that require certain oxygen levels for survival.

Persistent Organic Pollutants (POPs)

Definition: Toxic chemicals that do not easily break down in the environment, leading to long-term ecological effects and health risks.

• Bioaccumulation: These pollutants build up in organisms over time, leading to increased concentrations as they move up the food chain, potentially causing endocrine disruption and cancer.

Solid Waste Disposal

Definition of Solid Waste: Any discarded nondurable material, which poses challenges for waste management systems worldwide.

Sanitary Landfill Construction:

• Utilizes liners to prevent harmful leachate from contaminating groundwater.

• Incorporates water collection systems for leachate management and sealing caps to cover waste to control odors and pests.

• Includes methane collection systems for energy recovery, converting waste into usable energy sources.

e-Waste: The disposal and recycling of old electronics can significantly reduce landfill contributions, requiring compliance with specific regulations to ensure hazardous components are managed safely.

Hazardous Waste Characteristics: Defined as ignitable, toxic, reactive, or corrosive materials that require specialized handling and disposal methods to protect human health and ecosystems.

Incineration for Energy Generation: The heat generated from burning waste can convert water to steam, which is then used to spin turbines and generate electricity, providing an alternative energy source while reducing landfill volumes.

Ocean Dumping Issues: The practice pollutes marine ecosystems, contributing to the formation of garbage patches and is often a cost-saving measure for waste management despite its environmental implications.

Pollution Management Strategies

Integrated Waste Management: A strategic approach that incorporates reusing, recycling, and reducing waste generation to minimize environmental impact.

Recycling Advantages/Disadvantages:

• Advantages: Reduces overall pollutants and conserves natural resources, supporting sustainability initiatives.

• Disadvantages: Certain items are non-recyclable and recycling processes can be costly, posing further challenges to waste management efforts.

Composting: An effective method for reducing landfill waste through the breakdown of organic material, turning it into nutrient-rich soil while managing pest populations is a crucial aspect of successful composting efforts.

Sewage Treatment Process

Primary Treatment: Involves the removal of large particles and sediments from wastewater through screening and settling processes.

Secondary Treatment: Employs bacteria to decompose organic matter in wastewater, significantly reducing biochemical oxygen demand (BOD).

Tertiary Treatment: Involves chemical processes to remove any remaining nutrients, ensuring treated wastewater meets environmental discharge standards.

Water Treatment Disinfectants:

• Chlorine for bacteria: Widely used for its effectiveness in eliminating pathogens.

• Ozone for viruses: Utilized for its ability to inactivate a wide range of viruses and other microorganisms.

• UV light for microbes: Used in some treatment processes for its capability to effectively disinfect without adding chemicals.

Lethal Dose (LD50) and Dose Response Curves

LD50 Definition: Refers to the dose of a substance that is lethal to 50% of a population in toxicity studies, providing valuable information on the toxicity of chemicals.

Dose Response Curve: A graphical representation showing how varying doses of a substance affect the response of organisms, illustrating the relationship between exposure level and health effect severity.

Pollution and Human Health: Pathogens/Diseases

Pathogen Effects:

• Dysentery: Often caused by contaminated water, leading to severe dehydration and illness.

• Mesothelioma: A type of lung cancer associated with asbestos exposure, with a long latency period.

• Tropospheric Ozone: An air pollutant that can exacerbate respiratory issues, particularly in vulnerable populations like children and the elderly.

• Zika Virus: Transmitted by mosquitoes, the virus presents significant risks, including potential birth defects in pregnant women.