Global Warming, Ozone Depletion, and Air Quality Analysis

Global Effects

The Greenhouse Effect

The greenhouse effect is the retention in the atmosphere of a portion of the heat emitted by the Earth's surface after it has warmed due to solar radiation. This process delays the release of thermal energy into outer space.

The concentration of gases in the atmosphere causes average temperatures on our planet to be around 15°C. Without these gases, it would be much colder. The main gas that absorbs terrestrial radiation is CO2, but water vapor also plays an important role.

Computer simulations predict significant changes by the end of the twenty-first century:

• An increase of between 1.5 and 6.5 ºC in average temperature.
• Changes in global rainfall patterns, with a tendency towards drought in some areas and increased rainfall in others.

Preventive measures to minimize global warming include substituting conventional energy sources with alternative, non-polluting ones.

Reduction of the Ozone Layer

The ozone layer is a part of the atmosphere with a gas composition similar to that on Earth's surface. The ozone hole is an area where the total amount of gas falls below set levels. It is a thinning of the layer, not a real hole. The main pollutants that deplete the ozone layer are:

• Chlorinated compounds: Freon or CFCs release chlorine atoms that react with ozone, breaking it into atomic and molecular oxygen.
• Methane: Produced by the metabolism of living organisms and the decomposition of organic matter. Once in the atmosphere, methane undergoes a process of photodissociation, producing hydrogen catalytic cycles that cause ozone destruction.
• Nitrogen oxides: These oxides break down ozone molecules in a process similar to that of methane.

Air Quality

The emission of pollutants is the production and release of atmospheric substances. Emission levels refer to the amount of pollutants released globally or from a particular source.

Network Monitoring and Forecasting of Air Pollution

Pollution control is carried out by the Network Monitoring and Forecast of Air Pollution (XVPCA). This network uses a system of measuring devices that provide automatic or manual data on air quality and emission levels. These data are analyzed and coordinated by centers. The functions of the XVPCA are:

• Understanding the evolution of pollution levels over time and across the territory.
• Informing citizens about air quality and its evolution.
• Complying with current regulations regarding the protection of the atmospheric environment, which establishes the need to assess levels of air pollutants.
• Identifying the main sources of emissions and their effects.
• Developing capacity and vulnerability maps of the territory.
• Undertaking sanitation actions in degraded areas.
• Implementing preventive measures in non-degraded areas.

Structure of XVPCA in Catalonia

- Sensors: These are the devices, manual or automatic, that measure the concentration of major air pollutants, i.e., emission levels.

- Analysis Centers: These institutions are in charge of generating, transmitting, and validating data related to air quality from the sampling points allocated to them.

- Data Receiver Center: This center coordinates and oversees the Analysis Centers and laboratories. It reports the air pollution situation to the Coordinator and conducts annual pollution surveys within its territory.

- Data Center Coordinator: This center oversees compliance with legislation and defines the criteria that govern the operation of the network. It also coordinates and oversees the Analysis Centers, manages air quality in its territory, and transmits information to concerned agencies.

The Catalan Air Quality Index

The Catalan Air Quality Index (ICQA) is a public information system on the state of air quality.