Outdoor air quality (AQI)
Introduction
Atmospheric pollution is the presence in the air of materials or forms of energy that imply risk, damage or serious discomfort for people and natural beings, as well as attacking different materials, reducing visibility or producing unpleasant odors and diseases. The air quality index (AQI) is a figure provided by the authorities of an area (usually urban) and that reflects the amounts of pollutants present in the air.[1] When the quality of the air is good (it has few pollutants), people can breathe it indefinitely without their health being affected. When it is harmful, eye irritations, all kinds of respiratory problems and even heart problems can occur.[2] If the air quality drops (or, due to atmospheric conditions, is expected to drop) below certain limits (which are different in each country), the authorities can take measures such as prohibiting the circulation of all vehicles that emit pollution, some of them, prohibiting the practice of outdoor sports or recommending the daily use of masks.
Technically, air quality, immission or limit value can be defined as the concentration of pollutant that reaches a receptor, more or less distant from the emission source.[3].
Factors
Currently controls and regulations have increased and the quality of fuels has also improved. However, vehicular traffic has increased exponentially, becoming the main source of pollution in cities. At a global level, it has been discovered that carbon dioxide emissions derived from the combustion of oil, coal and natural gas are playing a decisive role in the increase in global temperature due to the greenhouse effect. Now, the main causes of poor air quality are[4] sulfur oxides, nitrogen oxides, tropospheric ozone (at low altitude, different from the stratospheric, which is very beneficial), carbon monoxide, volatile organic compounds and suspended particles.
The main anthropogenic sources (of human origin, also called anthropogenic, but this term is not included in the RAE)[5] of air pollution are:
Air quality can also be compromised by natural causes such as:
The fight against air pollution is carried out on the following fronts: