Earth’s Subsystems and Pollution: A Comprehensive Look
Earth’s Interacting Subsystems
Within the Earth system, we can differentiate several interacting subsystems: the atmosphere (gaseous envelope), the geosphere (the solid Earth formed by rocks and minerals), the hydrosphere (inland waters, seas, and oceans), and the biosphere (all living organisms on the planet). All Earth system components are interdependent and supportive. What occurs in one subsystem will have consequences on the other subsystems; thus, there is a dynamic equilibrium.
Examples:
- The regulation of Earth’s climate, in which all the subsystems are involved, but especially the atmosphere and hydrosphere. The alterations caused by the enhanced greenhouse effect show the extent to which all terrestrial components interact.
- The maximum degree of relationship is in the biosphere for all other subsystems. In a broad sense, it includes all living beings, the physical environment on which they live, and the relationships that exist between them.
The geosphere provides substrate and a source of inorganic nutrients to terrestrial ecosystems. The hydrosphere and atmosphere also interact with the biosphere through CO2 and O2 exchange with living beings. But life not only depends on the physical environment: it was precisely biological processes that drastically altered the characteristics of the medium (such as the composition of the atmosphere, which owes its oxygen to photosynthesis, or various features of the oceans, and its content in salts).
Pollution: Causes and Types
Pollution is the increase or appearance of harmful substances and harmful or certain forms of energy in the environment, in quantities that this environment cannot neutralize. It is important to note that, in general, the quantity is more important than the type of contaminants. The current problems of pollution started in the late 17th century with the Industrial Revolution. Its effects can be local, regional, or global.
Causes
Contamination may be due to natural biological and geological processes or caused by human (anthropogenic) activities. Natural contamination is caused by volcanic eruptions, forest fires, dust storms in deserts, microorganism activity, and others. Anthropogenic pollution has increased dramatically since the Industrial Revolution, due to fossil fuel use, the exponential growth of humanity, and resource consumption.
Types
- Physical contamination is due to changes in the physical characteristics of the atmosphere and water, such as thermal noise and radiation.
- Chemical contamination is caused by a particular chemical compound.
- Biological contamination is due to the action of certain organisms.
Atmospheric Pollution
Air pollution has become a serious problem that not only affects health but also prevents the normal development of vegetation and deteriorates buildings and monuments. The main air pollutants come from the use of fossil fuels in industries and vehicles, certain industrial processes, and mining.
Types of Pollutants
- Primary pollutants: Dangerous substances emitted directly into the atmosphere, such as carbon oxides, sulfur, and nitrogen.
- Secondary pollutants: Produced by chemical reactions between primary pollutants in the atmosphere, such as ozone.
Some effects of air pollutants affect the entire planet, such as acid rain, the destruction of the ozone layer, and global warming. In other cases, the effects are local, such as photochemical smog or indoor pollution.
Winter Smog
Winter smog is dense, polluted air (mixed with particles of smoke, haze, soot, and sulfur) resulting from coal combustion that covers cities, often reducing visibility.
Photochemical Smog
Photochemical smog is a kind of dark orange haze. Summer is the worst season for this type of smog, which is why it is also called summer smog. It is formed from primary pollutants such as oxides and volatile organic compounds that react with each other and with oxygen. Traffic emissions are responsible for between 50 and 70% of this type of contamination. Normally, these polluting gases ascend to the upper atmosphere, dragged by hot air.