Studied by 4 people
APES 2024
Air pollution
The introduction of chemicals, particulate matter, or microorganisms into the atmosphere at concentrations high enough to harm plants, animals, and materials such as buildings, or to alter ecosystems
Natural emissions of pollution include
volcanoes
lightning
forest fires
plants, both living and dead
Natural emissions of pollution all
release compounds that can be classified as pollutants
Anthropogenic sources include
on-road vehicles, power plants, industrial processes, waste disposal (incinerator)
Anthropogenic
human-caused
Residence time
the time a pollutant stays in the atmosphere
Pollutants with brief residence times exert
localized impacts over short time periods
ex. Particulate matter, automobile exhaust
Pollutants with long residence times exert
regional or global impacts (Pollutants causing climate change or ozone depletion)
The EPA sets nationwide standards for
emissions and concentrations of toxic pollutants
States monitor
air quality and the EPA takes over enforcement if plans are inadequate
Criteria pollutants
pollutants that pose especially great threats to human health
Criteria pollutant examples
Carbon monoxide
sulfur dioxide
nitrogen dioxide,
tropospheric ozone
particulate matter
lead
Carbon monoxide
common emission in vehicle exhaust
can be a significant component of air pollution in urban areas
Problem in developing countries where people may cook with manure, charcoal or kerosene indoors
Incomplete combustion of any kind
Sulfur dioxide (SOx)
A corrosive gas that comes primarily from combustion of fuels, ex. coal, oil, gasoline
A respiratory irritant and can adversely affect plant tissue
Also released in large quantities during volcanic eruptions and in much smaller quantities, during forest fires
Nitrogen Oxides (NOx)
Motor vehicles and stationary fossil fuel combustion are primary anthropogenic
sources
Respiratory irritant, increases susceptibility to respiratory infection
An ozone precursor, leads to formation of photochemical smog
Converts to nitric acid in atmosphere, is harmful to aquatic life and some vegetation
Contributes to over-fertilizing terrestrial and aquatic systems.
Ozone (O3)
Secondary pollutant
formed when heat and sunlight cause chemical reactions between oxides of
nitrogen (NOX) and Volatile Organic Compounds (VOCs), also known as Hydrocarbons
reaction can occur both near the ground and high in the atmosphere.
Types of ozone
Tropospheric ozone – bad ozone
Stratospheric ozone – good ozone
How does ozone smell?
sweet
Particulate matter (PM)
Solid or liquid particles suspended in air
Types of particulate matter
PM 2.5 – diameter less than 2.5 micrometers (fine particles)
PM 10 – diameter less than 10 micrometers
Particulate matter comes from
Burning of coal, oil, diesel, biofuels
Agriculture, road construction
Particulate matter can be
natural or anthropogenic
Particulate matter in the atmosphere ranges considerably in size and can
absorb or scatter light, creates a haze and reduces the light that reaches the surface of Earth
Lead
A gasoline additive, also found in oil, coal, and old paint
Impairs central nervous system
At low concentrations, can have measurable effects on learning and ability to concentrate
Carbon dioxide (CO2)
released by burning fossil fuels has led to
its becoming a major concern
Appears naturally from respiration, decomposition and volcanic eruptions
Not a criteria pollutant
Is a greenhouse gas and does lead to Earth’s warming
CO2 recently exceeded a concentration of
400 parts per million (ppm) in the atmosphere and appears to be steadily increasing each year
Volatile organic compound (VOC)
An organic compound that evaporates or sublimates at room temperatures
Formed by evaporation of fuels, solvents, paints, and improper combustion of fuels such as gasoline
A precursor to ozone formation
Volatile organic compound (VOC) examples
formaldehyde and gasoline
Trees are a natural source of VOCs
Note 
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