6  Conclusions
Based on the data collection of the concentration of the most harmful particles for health (PM2.5), in the different capital cities of the world, a comparative analysis of the concentration was carried out during a typical time of normal mobility and during the lockdown. The behavior patterns show as a result a decrease in their concentration during the confinement season, favorably restoring the air quality of most cities analyzed. If these data are subsequently correlated with the activities stopped during the confinement of each city, one can think of public policies that promote new socio-ecological models, as well as coherent environmental policies in these adaptive environments that are the cities. In general, the results showed that automobile demobilization and factory shutdowns play an important role in reducing pollution in capitals. For the fifty countries analyzed, Bogotá (Colombia)(Insider, 2019), as one of the cities with the most traffic in the world, with a 65% concentration of traffic during the day, presents the PM2.5 greatest reduction. during the period of confinement with 57%. Likewise, Delhi (India), the most polluted capital city in the world, presents a decrease in PM2.5 contamination of 40%. Some specific conclusions of the research are: i. During lockdown, Europe maintains a Good AQI level of less than 50 μg/m3, followed by America with a Moderate AQI level (57 μg/m3), Asia (82 μg/m3) and Africa (95 μg/m3). ii. America presented the highest distinction in the PM2.5 decrease air pollution. between a typical period of conventional mobility and a period of confinement, with a reduction of 22%. iii. The capitals that in typical days (BQut) present a moderate AQI level and which presented a PM2.5 decrease between 60% and 20% during the period of confinement (Qut), such as: Bogotá, Kubait City, Delhi, Tehran, Taskhkent, Ulaanbaatar, kabul and Colombo; They must present alternatives to reduce the displacement of fossil fuel vehicles and stricter regulations for their factories.
This study considered the relationship between population and Pp/ES air quality stations, where the number of stations per inhabitant is obviously higher in developed countries than in emerging countries. Therefore, it is important to consider that the lack of access to data on air pollution, especially in emerging countries and where the use of public and private transport systems is high, causes errors or alterations in real information on the state of air quality.