Atmospheric Pollutants
4.2: Atmospheric Pollutants
Atmospheric pollution is the presence of harmful substances in the atmosphere, damaging to organisms and the environment.
Smoke and Smog
Smoke: A complex mixture of gases and small particles resulting from combustion.
Smog: A type of air pollution that is a mixture of smoke and other atmospheric pollutants, including ground-level ozone, forming a visible haze.
Types of Smog:
Sulfurous Smog:
Also known as "London smog."
Occurs when high levels of sulfur oxides (from fossil fuel combustion) combine with particles in the air.
Characterized by high concentration of sulfur dioxide (SO_2) and particulate matter.
Photochemical Smog:
Also called "Los Angeles smog."
Formed when sunlight triggers chemical reactions between pollutants including nitrogen oxides (NO_x) and volatile organic compounds (VOCs).
Often contains ozone (O_3), prevalent in urban areas with vehicular traffic.
Particulate Sizes
PM10: Particles with diameters that are 10 micrometers and smaller. Inhalable into the lungs, causing adverse health effects.
(PM_{10}) : d \leq 10 \mu m
PM2.5: Fine particulate matter with diameters that are 2.5 micrometers and smaller. Can penetrate deep into the lungs and enter the bloodstream, posing greater health risks.
(PM_{2.5}) : d \leq 2.5 \mu m
Toxic Chemicals in Smog
Polycyclic Aromatic Hydrocarbons (PAHs): Carcinogenic organic pollutants found in smoke.
Heavy Metals: Lead, mercury, and cadmium from industrial processes, with toxic effects.
Formaldehyde and Acrolein: Irritating chemicals from incomplete combustion of organic matter.
Benzene: A carcinogenic VOC commonly found in vehicle emissions.
Nitrogen Dioxide (NO2): A reddish-brown toxic gas, a significant component of smog.
Synergistic Action with Other Atmospheric Pollutants
Smog and smoke often exhibit synergistic effects, where the combined effect is greater than the sum of individual effects.
Ozone: Reacts with particulate matter in smoke to produce a more toxic environment. A powerful respiratory irritant exacerbating particulate matter's health effects.
Sulfur Dioxide (SO_2): Adheres to particles in the presence of particulate matter, facilitating entry into the respiratory system, potentially causing severe health problems.
VOCs: Interact with (NO_x) in sunlight to produce additional ozone, increasing the overall toxicity of smog.
Health Impacts of Smoke and Smog
Significant, leading to respiratory infections, heart disease, and lung cancer.
Vulnerable populations: Those with pre-existing conditions, children, the elderly, and outdoor workers.
Regulations and control measures focus on limiting emissions from vehicles and industrial sources, promoting clean energy, and enforcing stricter air quality standards.
Public information about air quality indexes and health advisories helps minimize exposure.
Effects of Smoke Pollution
Far-reaching, impacting human health, ecosystems, non-living objects, the climate, and atmospheric layers, including the stratosphere.
On Humans:
Primarily affects respiratory health, leading to asthma, chronic obstructive pulmonary disease (COPD), and acute respiratory infections.
Fine particulate matter (PM_{2.5}) can penetrate deep into the lungs and enter the bloodstream, causing cardiovascular issues, chronic bronchitis, and increased risk of stroke and lung cancer.
Irritates the eyes, nose, and throat; exacerbates allergies.
On Other Living Organisms:
Animals: Similar effects as humans—respiratory problems and irritation. Wild animals may flee their habitat, leading to ecological imbalances, and chronic exposure can affect reproductive success and lifespan.
Plants: Blocks sunlight, reducing photosynthesis. Acidic compounds harm plant tissues and alter soil chemistry.
Aquatic Life: Particulate matter and toxic chemicals settle on water bodies, affecting water quality and decreasing oxygen levels.
On Non-Living Objects:
Causes physical damage to buildings and cultural heritage due to acidic particle deposition, corroding metals and eroding stone and paint. Soils fabrics, reducing lifespan and aesthetic quality of materials
On the Climate:
Global Warming: Black carbon (soot) in smoke reduces the albedo effect (reflection of sunlight), causing increased melting.
Temperature Regulation: Smoke particles can absorb and reflect sunlight, either warming the air or leading to cooling by blocking sunlight.
On the Atmosphere:
Visibility: Reduces visibility, scattering and absorbing light, hazardous for transportation.
Air Quality: Degrades air quality, contributing to smog formation.
On the Stratosphere:
Chemical Reactions: Smoke constituents can contribute to chemical reactions that lead to ozone layer depletion.
Cooling of the Stratosphere: Sulfate aerosols and other particles can lead to the cooling of the stratosphere.
The Difference Between Smoke and Smog
Smoke and smog are both forms of air pollution. They originate from different sources and have distinct compositions and effects.
Smoke:
Origin: Result of combustion, made up of gases and fine particles produced when wood and organic materials burn. Sources include wildfires and burning fossil fuels.
Composition: Includes carbon monoxide, carbon dioxide, particulate matter (ash and soot), volatile organic compounds (VOCs), and toxic chemicals like polycyclic aromatic hydrocarbons (PAHs).
Effects: Primarily affects the respiratory system of living beings, causing irritation and long-term health effects. Reduces visibility and damages vegetation and structures.
Smog:
Origin: Originally a mixture of smoke and fog, modern smog (photochemical smog) forms by the reaction of sunlight with pollutants such as nitrogen oxides (NOx) and VOCs from vehicles and industrial facilities.
Composition: Consists of ground-level ozone (O3), particulate matter, sulfur dioxide (SO2), VOCs, and (NO_x).
Effects: Has a broader impact, affecting indoor and outdoor air quality, leading to respiratory issues and long-term health effects like chronic obstructive pulmonary disease (COPD). Reduces visibility and contributes to the urban heat island effect.
Key Differences:
Formation Process: Smoke is directly emitted from combustion, while smog is formed by chemical reactions in the atmosphere.
Appearance: Smoke tends to be thicker, ranging from white to black. Smog often gives the air a hazy, brownish appearance.
Presence: Smoke is localized to the source of combustion. Smog is associated with urban areas and can cover larger regions.
The London Smog, 1952
The London smog of 1952, also known as the Great Smog of London, was a severe air-pollution event in early December 1952.
A period of cold weather combined with an anticyclone and windless conditions collected airborne pollutants—mostly arising from the use of coal—to form a thick layer of smog over the city. It lasted from Friday, 5 December, to Tuesday, 9 December 1952, and then dispersed quickly after the weather changed.
Events Leading to the Smog:
Industrial Activity: Post-war London relied heavily on coal for residential heating and industrial energy.
Domestic Heating: Colder temperatures led to increased burning of coal in homes.
Weather Conditions: Cold, stagnant weather caused smoke and pollutants to be trapped due to temperature inversion.
Impacts of the Smog:
Health Effects:
An estimated 4,000 people died prematurely due to respiratory tract infections.
Another 8,000 to 12,000 deaths are believed to have been hastened by the smog's effects.
Visibility: Reduced to a few yards, disrupting transport services and increasing accidents.
Environmental Impact: Detrimental effects on flora, fauna, soil, and structures.
Response and Legacy:
Public Outcry: Increased awareness of the relationship between coal burning and air pollution.
Clean Air Acts: The UK government introduced the Clean Air Acts of 1956 and 1968, providing regulations.
Designation of
4.2: Atmospheric Pollutants
Atmospheric pollution is the presence of harmful substances in the atmosphere, damaging to organisms and the environment.
Smoke and Smog
Smoke: Mixture of gases and particles from combustion.
Smog: Air pollution mixing smoke and pollutants like ground-level ozone, forming haze.
Types of Smog:
Sulfurous Smog: From sulfur oxides (fossil fuels) and particles. High SO_2 and particulate matter.
Photochemical Smog: Sunlight triggers reactions between NOx and VOCs, with ozone (O3). Common in urban areas.
Particulate Sizes
PM10: Particles ≤ 10 μm, inhalable, causing health effects. (PM_{10}) : d \leq 10 \mu m
PM2.5: Fine particles ≤ 2.5 μm, penetrate deep into lungs, greater health risks. (PM_{2.5}) : d \leq 2.5 \mu m
Toxic Chemicals in Smog
PAHs: Carcinogenic organic pollutants in smoke.
Heavy Metals: Lead, mercury, cadmium from industry, toxic.
Formaldehyde and Acrolein: Irritating from incomplete combustion.
Benzene: Carcinogenic VOC in vehicle emissions.
Nitrogen Dioxide (NO2): Reddish-brown toxic gas in smog.
Synergistic Action with Other Atmospheric Pollutants
Combined effects greater than individual effects.
Ozone: Reacts with particulate matter, increasing toxicity.
Sulfur Dioxide (SO_2): Adheres to particles, causing respiratory issues.
VOCs: Interact with (NO_x) to produce ozone, increasing toxicity.
Health Impacts of Smoke and Smog
Significant, causing respiratory infections, heart disease, lung cancer. Vulnerable populations include those with pre-existing conditions, children, elderly, and outdoor workers. Control measures limit emissions and promote clean energy.
Effects of Smoke Pollution
Impacting human health, ecosystems, non-living objects, climate, and atmosphere.
On Humans:
Respiratory issues, cardiovascular effects from (PM_{2.5}), irritation of eyes, nose, and throat.
On Other Living Organisms:
Animals: Respiratory problems, habitat disruption, reproductive issues.
Plants: Reduced photosynthesis, tissue damage, altered soil.
Aquatic Life: Water quality decline, decreased oxygen.
On Non-Living Objects:
Physical damage by acidic deposition, corrosion.
On the Climate:
Global Warming: Black carbon reduces albedo, increasing melting.
Temperature Regulation: Particles absorb/reflect sunlight, causing warming/cooling.
On the Atmosphere:
Visibility: Reduced visibility, hazardous for transportation.
Air Quality: Degraded air quality, smog formation.
On the Stratosphere:
Chemical Reactions: Contribute to ozone depletion.
Cooling: Sulfate aerosols cool the stratosphere.
The Difference Between Smoke and Smog
Smoke from combustion, smog from atmospheric chemical reactions.
Smoke:
Origin: Combustion, e.g., wildfires, fossil fuels.
Composition: Carbon monoxide, carbon dioxide, particulate matter, VOCs, PAHs.
Effects: Respiratory issues, visibility reduction, damages vegetation.
Smog:
Origin: Sunlight reaction with NO_x and VOCs.
Composition: Ground-level ozone, particulate matter, (SO2), VOCs, (NOx).
Effects: Respiratory issues, COPD, reduces visibility.
Key Differences:
Formation: Smoke is emitted, smog is formed by reactions.
Appearance: Smoke is thicker, smog is hazy/brownish.
Presence: Smoke is localized, smog is widespread in urban areas.
The London Smog, 1952
Severe air pollution in December 1952.
Events Leading to the Smog:
Industrial Activity: Heavy coal reliance.
Domestic Heating: Increased coal burning due to cold.
Weather Conditions: Stagnant weather trapped pollutants.
Impacts of the Smog:
Health Effects: 4,000+ premature deaths from respiratory issues.
Visibility: Reduced, disrupting transport.
Environmental Impact: Harmed flora, fauna, soil, structures.
Response and Legacy:
Public Outcry: Increased awareness.
Clean Air Acts: Regulations introduced in 1956 and 1968.
4.2: Atmospheric Pollutants
Atmospheric pollution involves harmful substances in the atmosphere, damaging organisms and the environment.
Smoke and Smog
Smoke: A complex mixture of gases and particles produced by combustion.
Smog: Air pollution that combines smoke with other pollutants, such as ground-level ozone, creating a visible haze.
Types of Smog:
Sulfurous Smog:
Also known as "London smog."
Results from high levels of sulfur oxides (from burning fossil fuels) combined with particles in the air.
Characterized by a high concentration of sulfur dioxide (SO_2) and particulate matter.
Photochemical Smog:
Also known as "Los Angeles smog."
Forms when sunlight triggers chemical reactions between pollutants, including nitrogen oxides (NO_x) and volatile organic compounds (VOCs).
Often contains ozone (O_3), and is prevalent in urban areas with vehicular traffic.
Particulate Sizes
PM10: Particles with diameters 10 micrometers or smaller. Inhalable into the lungs, causing adverse health effects.
(PM_{10}) : d \leq 10 \mu m
PM2.5: Fine particulate matter with diameters 2.5 micrometers or smaller. Can penetrate deep into the lungs and enter the bloodstream, posing greater health risks.
(PM_{2.5}) : d \leq 2.5 \mu m
Toxic Chemicals in Smog
Polycyclic Aromatic Hydrocarbons (PAHs): Carcinogenic organic pollutants found in smoke.
Heavy Metals: Lead, mercury, and cadmium from industrial processes, with toxic effects.
Formaldehyde and Acrolein: Irritating chemicals from incomplete combustion of organic matter.
Benzene: A carcinogenic VOC commonly found in vehicle emissions.
Nitrogen Dioxide (NO2): A reddish-brown toxic gas and a significant component of smog.
Synergistic Action with Other Atmospheric Pollutants
Smog and smoke often exhibit synergistic effects, where the combined impact is greater than the sum of their individual effects.
Ozone: Reacts with particulate matter in smoke to produce a more toxic environment. A powerful respiratory irritant that exacerbates the health effects of particulate matter.
Sulfur Dioxide (SO_2): Adheres to particles in the presence of particulate matter, facilitating entry into the respiratory system, potentially causing severe health problems.
VOCs: Interact with (NO_x) in sunlight to produce additional ozone, increasing the overall toxicity of smog.
Health Impacts of Smoke and Smog
Significant, leading to respiratory infections, heart disease, and lung cancer.
Vulnerable Populations: Those with pre-existing conditions, children, the elderly, and outdoor workers.
Regulations and control measures focus on limiting emissions from vehicles and industrial sources, promoting clean energy, and enforcing stricter air quality standards.
Public information about air quality indexes and health advisories helps minimize exposure.
Effects of Smoke Pollution
Reaching far, impacting human health, ecosystems, non-living objects, the climate, and atmospheric layers, including the stratosphere.
On Humans:
Primarily affects respiratory health, leading to asthma, chronic obstructive pulmonary disease (COPD), and acute respiratory infections.
Fine particulate matter (PM_{2.5}) can penetrate deep into the lungs and enter the bloodstream, causing cardiovascular issues, chronic bronchitis, and an increased risk of stroke and lung cancer.
Irritates the eyes, nose, and throat and exacerbates allergies.
On Other Living Organisms:
Animals: Can suffer similar effects as humans, including respiratory problems and irritation. Wild animals may flee their habitat, leading to ecological imbalances, and chronic exposure can affect reproductive success and lifespan.
Plants: Smoke can block sunlight, which reduces photosynthesis. Acidic compounds can harm plant tissues and alter soil chemistry.
Aquatic Life: Particulate matter and toxic chemicals can settle on water bodies, affecting water quality and decreasing oxygen levels.
On Non-Living Objects:
Causes physical damage to buildings and cultural heritage due to acidic particle deposition, corroding metals and eroding stone and paint. Soils fabrics, reducing the lifespan and aesthetic quality of materials
On the Climate:
Global Warming: Black carbon (soot) in smoke reduces the albedo effect (reflection of sunlight), causing increased melting.
Temperature Regulation: Smoke particles can absorb and reflect sunlight, either warming the air or leading to cooling by blocking sunlight.
On the Atmosphere:
Visibility: Reduces visibility by scattering and absorbing light, which is hazardous for transportation.
Air Quality: Degrades air quality, contributing to smog formation.
On the Stratosphere:
Chemical Reactions: Smoke constituents can contribute to chemical reactions that lead to ozone layer depletion.
Cooling of the Stratosphere: Sulfate aerosols and other particles can lead to the cooling of the stratosphere.
The Difference Between Smoke and Smog
Smoke and smog are both forms of air pollution but originate from different sources and have distinct compositions and effects.
Smoke:
Origin: Results from combustion and is made up of gases and fine particles produced when wood and organic materials burn. Sources include wildfires and burning fossil fuels.
Composition: Includes carbon monoxide, carbon dioxide, particulate matter (ash and soot), volatile organic compounds (VOCs), and toxic chemicals like polycyclic aromatic hydrocarbons (PAHs).
Effects: Primarily affects the respiratory system of living beings, causing irritation and long-term health effects. Reduces visibility and damages vegetation and structures.
Smog:
Origin: Smog (photochemical smog) forms by the reaction of sunlight with pollutants such as nitrogen oxides (NO_x) and VOCs from vehicles and industrial facilities.
Composition: Consists of ground-level ozone (O3), particulate matter, sulfur dioxide (SO2), VOCs, and (NO_x).
Effects: Has a broader impact, affecting indoor and outdoor air quality, leading to respiratory issues and long-term health effects like chronic obstructive pulmonary disease (COPD). Reduces visibility and contributes to the urban heat island effect.
Key Differences:
Formation Process: Smoke is directly emitted from combustion, while smog is formed by chemical reactions in the atmosphere.
Appearance: Smoke tends to be thicker, ranging from white to black. Smog often gives the air a hazy, brownish appearance.
Presence: Smoke is localized to the source of combustion, whereas smog is associated with urban areas and can cover larger regions.
The London Smog, 1952
The London smog of 1952, also known as the Great Smog of London, was a severe air-pollution event in early December 1952.
A period of cold weather combined with an anticyclone and windless conditions collected airborne pollutants—mostly arising from the use of coal—to form a thick layer of smog over the city. It lasted from Friday, December 5, to Tuesday, December 9, 1952, and then dispersed quickly after the weather changed.
Events Leading to the Smog:
Industrial Activity: Post-war London relied heavily on coal for residential heating and industrial energy.
Domestic Heating: Colder temperatures led to increased burning of coal in homes.
Weather Conditions: Cold, stagnant weather caused smoke and pollutants to be trapped due to temperature inversion.
Impacts of the Smog:
Health Effects:
An estimated 4,000 people died prematurely due to respiratory tract infections.
Another 8,000 to 12,000 deaths are believed to have been hastened by the smog's effects.
Visibility: Reduced to a few yards, disrupting transport services and increasing accidents.
Environmental Impact: Detrimental effects on flora, fauna, soil, and structures.
Response and Legacy:
Public Outcry: Increased awareness of the relationship between coal burning and air pollution.
Clean Air Acts: The UK government introduced the Clean Air Acts of 1956 and 1968, providing regulations.