Understanding Air Pollution: Sources, Types, and Impacts
Air Pollution: An Overview
Air pollution: The presence in the air of substances or forms of energy that imply danger, harm, or serious inconvenience for people and goods of any nature.
Sources of Contamination
- Natural: The activity of the geosphere and the biosphere. Volcanic eruptions release sulfur compounds. Respiration processes of living beings increase the amount of CO2 in the atmosphere. The decomposition of anaerobic organic matter produces methane. Other emission sources are fires and electrical storms.
- Artificial or Anthropogenic: Result from the presence and activities of humans, primarily from the burning of fossil fuels.
Types of Pollution
Components: Biogeochemical cycles of carbon, nitrogen, oxygen, and sulfur are self-regulated by different mechanisms. However, human activities accelerate and disrupt their equilibrium, mobilizing reserves and causing air pollutants.
Air Pollutants
Air pollutants are substances and forms of energy that, in certain concentrations, can cause discomfort, damage, or risks to people and other living beings. They can also disturb the functioning of ecosystems, material goods, and the climate.
Residence Time
The time a pollutant may remain in the atmosphere on its own or participate in various chemical reactions. Residence time varies depending on the nature of each pollutant.
Chemical Substances
- Primary pollutants are substances of varied chemical nature and composition directly emitted into the atmosphere from various identified sources.
- Secondary pollutants originate from primary pollutants through chemical reactions in the atmosphere, forming new pollutants by transforming existing ones. They do not come from direct emission sources.
Forms of Energy
Ionizing Radiation
Particles or electromagnetic waves that ionize atoms or molecules, directly altering their chemical structure and functions. They are classified as:
- Alpha and beta particles are electrically charged. Alpha particles have less penetration power than beta particles.
- X-rays and gamma rays, being electromagnetic waves, have high penetration power, resulting in greater effects on human beings.
Non-ionizing Radiation
Electromagnetic waves that do not change the structure of matter because they do not cause ionization. They originate from the sun and the Earth. Examples include surface ultraviolet radiation, infrared, radio frequencies, and microwaves. They can alter the nervous, hormonal, and immunological systems, elevate body temperature, and induce electric currents in living tissues.
Noise
A type of atmospheric pollution with a major impact on the population.
Dispersion of Pollutants
Emission
The amount of pollutants poured into the atmosphere by an emission source in a determined time period. Values are measured at the outlet of the emission source. The evolution of pollutants depends on weather phenomena.
Susceptibility
The quantity of pollutants in a determined atmosphere once they have been transported, disseminated, and mixed, and to which living things and materials are exposed. If immission levels are not adequate, it lowers air quality and causes negative effects on recipients.
Factors Influencing Dispersion
Factors influencing the dynamics of pollutant dispersion and, therefore, their concentration, are the characteristics of emissions, weather conditions, and geographical and topographical features.