What is the process of risk assessment?
Why is it important in toxicology?
What is the importance of the threshold effect of environmental toxins?
What is the process of risk assessment in toxicology and how can it be used to evaluate the risk to human health and life?
What controversial issues can develop with the use of risk assessment?
What is the Precautionary Principle and how does it apply to environmental health?
Characteristics of the Atmosphere
The layers of the atmosphere are based on temperature gradients and include the troposphere, stratosphere, mesosphere, thermosphere, and exosphere.
What gases are used and expelled by photosynthesis and respiration?
What are the characteristics of Earth's atmosphere?
How does the atmosphere moderate Earth's temperature?
What are the two major atmospheric gases (in the troposphere) and what roles do they play?
Why does more solar radiation of all wavelengths come into the exosphere than reaches Earth's surface?
Air Pollution and Sources
Coal combustion releases air pollutants including carbon dioxide, sulfur dioxide, toxic metals, and particulates.
The combustion of fossil fuels releases nitrogen oxides into the atmosphere. They lead to the production of ozone, formation of photochemical smog, and convert to nitric acid in the atmosphere, causing acid rain. Other pollutants produced by fossil fuel combustion include carbon monoxide, hydrocarbons, and particulate matter.
Through the Clean Air Act, the Environmental Protection Agency (EPA) regulated the use of lead, particularly in fuels, which dramatically decreased the amount of lead in the atmosphere.
Reduction of Air Pollutants
A catalytic converter is an air pollution control device for internal combustion engines that converts pollutants (CO, NOx, and hydrocarbons) in exhaust into less harmful molecules (CO2, N2, O2, and H2O).
Nitric oxides that cause acid deposition come from motor vehicles and coal-burning power plants. Sulfur dioxides that cause acid deposition come from coal-burning power plants.
Acid deposition mainly affects communities that are downwind from coal-burning power plants.
Where does most of the acid rain fall and what damage can it do?
Indoor Air Pollutants
Common human-made indoor air pollutants include insulation, Volatile Organic Compounds (VOCs) from furniture, paneling and carpets; formaldehyde from building materials, furniture, upholstery, and carpeting; and lead from paints.
Common combustion air pollutants include carbon monoxide, nitrogen oxides, sulfur dioxide, particulates, and tobacco smoke.
Some effects of noise pollution on animals in ecological systems include stress, the masking of sounds used to communicate or hunt, damaged hearing, and causing changes to migratory routes.