Understanding Air Pollution: Causes and Effects

Air Pollution Introduction

• Air pollution introduces chemicals, primarily in the troposphere, that can harm organisms, ecosystems, and materials, while also altering the climate.
• Sources can be traced to both human activities like factories or cars, and natural phenomena such as forest fires or volcanic eruptions.
• The discovery of fire marked the beginning of human-induced air pollution, affecting both indoor and outdoor environments initially as a local issue.
• Urban development and reliance on chimneys, large-scale industries, and fossil fuel transportation expanded air pollution beyond local levels, creating widespread environmental challenges.

Ambient Air Pollution Event Examples

• The detrimental effects of air pollution on human health have been recognized for over 2500 years.
• A clear link between air pollution and health issues, even death, became evident following some severe air pollution events.
• In 1930, the Meuse Valley in Belgium experienced an industrial air pollution incidence combined with specific climatic conditions, leading to over 60 deaths and mortality rates exceeding ten times the normal rate.
• In October 1948, Donara, Pennsylvania, was enveloped in a lethal haze due to industrial pollution from steel and zinc smelters and an air inversion, resulting in over 20 deaths, six times above the usual mortality rate.
• London Smog 1952: The World's Worst Air Pollution Disaster happened in 1952.
• In the 1950s, high pollutant concentrations became common in London and were above standard levels.
• An unprecedented air pollution event took place.
• Several factors contributed to the polluted air levels, including:
  • Coal as a primary method for home heating
  • More coal was burned due to a particularly cold winter.
  • Limited dispersion of pollutants due to stagnant atmospheric conditions
  • The levels of SO2 & PM were much above British standards.
• The consequences included:
  • High concentrations of pollutants trapped inside the city
  • Residents became disoriented because visibility was reduced to almost zero
  • Traffic and schools were stopped due to the reduced visibility
  • Theater performance was stopped because pollution had seeped into the auditorium
  • Sickness and deaths increased followed by the rise in air pollution
  • Mortality rose about 3 times the standard level (10,000-12,000 deaths) and did not come back to normal until months after the fog.
  • Hospital admission rose drastically.
• In response to events like Donora and London, governments, namely the U.S. and U.K., initiated research to better understand the health risks of air pollution and introduced legislation to enhance air quality standards.
• Examples of regulations include:
  • U.K Clean Air Act (1956).
  • U.S Clean Air Act (1963).
• The UK Clean Air Act restricted coal burning in urban areas, authorized local councils to establish smoke-free zones, and provided homeowners grants for converting from coal to alternative heating systems.
• Air pollutants remain high in many cities, the industrialized world rarely experiences air pollution events like the London 1952 Smog, thanks to regulatory actions.

Major Ambient Air Pollutants

• Lead's major sources include leaded fuel, lead batteries, and metal processing, resulting in health effects such as accumulation in organs/tissues, learning disabilities, cancer, and nervous system damage.
• Sulfur Dioxide's major sources include fossil fuel combustion, oil refineries, organic matter composition, and volcanic eruptions, causing lung impairment and respiratory problems.
• Carbon Monoxide's major sources include fossil fuel combustion and forest fires, resulting in interference with oxygen delivery, headache, fatigue, dizziness, and neurological damage.
• Particulate Matter's major sources include fossil fuel burning and forest fires, causing respiratory symptoms, decline in lung functions, cardiovascular diseases, and mortality.
• Nitrogen Oxides' major sources include fossil fuel combustion, kerosene heaters, and soil biological processes, causing lung function decrease and respiratory infections.
• Ozone is formed in the presence of sunlight and can cause lung function decrease, increased respiratory symptoms, eye irritation, and bronchoconstriction.
• Hazardous Pollutants' (ex: asbestos, mercury...) major sources include industrial processes and paint thinner/fuel, reproductive problems, neurological damage, cancer, and respiratory problems.
• Volatile Organic Compounds' (ex: benzene...) major sources include fuel combustion, glue, forest fires, and vegetation, causing respiratory tract irritation, nausea, and cancer.
• Biological Pollutants' major sources include central air conditioners, grass, trees, and animals, causing allergies, fatigue, asthma, and respiratory problems.
• Ambient air pollutants are categorized as:
  • Primary: Direct pollutants such as sulfur dioxide from factories.
  • Secondary: Resulting from reactions of primary pollutants, like smog.

Ambient Air Pollution Effects

• Air pollution can have many negative effects, including;
  • Effect on Human Health
  • Effect on Visibility
  • Effect on Property
  • Effect on water Resources
  • Effect on living things
• Effect on Human Health
  • When the air is polluted, people breath ozone, particles, and harmful gases that can affect their health (lungs/heart problems, cancer).
  • People with some diseases (asthma, severe bronchitis...)
  • Elderly people
  • Children’s lungs are still growing, so they are vulnerable to air pollution exposure.
• Effect on Visibility
  • Smog (smoke mixed with fog and/or mixed with air pollutants)
  • Some dark particles (carbon...) can help to produce the haze by absorbing solar radiation & scatters sunlight
  • Excessive haze can reduce the amount of sunlight reaching the earth which can change of climate over time. Sometimes this can be reduced by as much as 35%.
• Effect on Property
  • Chemical air pollutants (acid rain) can dissolve paints and/or eat away materials, such as metals and limestone.
  • Air pollution can harm buildings, monuments, and other structures.
  • Repairing damage caused by air pollution, especially historic structures, can be expensive.
• Effect on Water
  • Air pollutants reach the water pollution when falling from the sky or when carried by rain/snow.
  • Nitrogen in the air can cause algae in the water to grow, impacting marine ecosystems.
  • Too much nitrogen in water can cause "Algal Bloom" blocking the sunlight, disturbing marine ecosystem or negatively affecting it.
  • Some algae are toxic; if eaten by animals toxins are introduced to their bodies
  • Burning fossil fuels can release sulfur dioxide and nitrogen oxides.
  • Sulfur dioxide & nitrogen oxide can dissolve in water (rain) and then they form acid.
  • Acidity in water can have dangerous effects to marine life and prevent them from reproducing.
  • Acid Rain is condensation of acidic water vapor in clouds.
  • The water can eventually cause the water environment to be difficult for some marine species, such as eggs from hatching.
  • Burning fossil fuels can release Mercury.
  • Some marine organisms (fish...) absorb Methyl Mercury into their bodies
  • If humans eat the affected marine life, methyl mercury can get into our bodies as well.
• Effect on Living Things
  • Air pollutants can harm plants and animals either Directly or Indirectly (by harming the habitat, the food or water needed for survival...).
  • Acid rain (occurs from Air pollution acid rain formation negative effects from acid rain) affects soil, plants and water bodies.
    • harming water bodies by changing the chemistry of water which negatively affects marine organisms (ex: fish...)
    • harming soil which no longer fits as a habitat for living things and no longer is a growing medium for plants.
    • harming plants since they cause damage to their leaves
  • Effects on the the Ozone Layer (occurs from air pollution ozone depletion occurrence negative effects from ozone depletion)
    • The role of the ozone is to reduce the amounts of UltraViolet Rays (UV) from reaching the earth.
    • If the ozone is destroyed in quantities by air pollutants, huge quantities of UV area reaching the earths surface.
    • Excessive UV is dangerous to living things and can cause cancer and damage to skin and lungs.
  • Global Warming effects (occurs from air pollution global warming occurrence negative effects from global warming)
    • Greenhouses gases are naturally present in the atmosphere to keep the earth warm and trap the sun's heat, and not allow the earth to freeze
    • Burning fossil fuels releases greenhouse gasses into the atmoshpere, resulting in less heat trapped inside the earth,
    • Global warming harms living things as it creates a lack of water, and in some species a hard time being able to adapt to the heat.

Air Pollution Prevention and Control

• The pathway from ambient air pollution to humans happens in 4 steps:
  • Step 1: Pollutants being released from the source
  • Step 2: Transportation of pollutants (by transport)
  • Step 3: Exposure (atmospheric deposition of the pollutant)
  • Step 4: Health response
• Ways to control air pollution:
  • Primary Prevention
    • Try to prevent or reduce the emission of the pollutants from the source.
    • Possible measures include:
      • Installing filters to remove emissions.
      • Reducing demand for power.
      • Switching to cleaner fuel.
      • Switching to renewable energy resources (sun, wind & water energy).
      • Promoting public transportation.
  • Setting Regulations & Standards
    • Methods to reduce Ambient air pollution include:
      • Setting Ambient Standards:
        • placing limits on the concentrations of specific pollutants in outdoor air, with allows for possible reducing emissions and areas with higher pollution levels.
      • Setting Emission Standards: - Limit the amount of air pollution that can be emitted from each source. - examples include limiting CO emissions from motor vehicles.
  • Taking Cleanup Measures
    • Cleaning up/removing the pollutants after they have been produced.
  • Using Personal protective equipment (PPEs)