The COVID-19 pandemic, and the sudden effects it had in the global economy and particularly the civilian aviation industry, offers a unique opportunity to examine the impacts of the latter on a local scale. Considering the decrease in activity in the Barcelona-El Prat airport from 2019 to 2020, it is possible to analyse the effects air transport has on a local level. Estimating the emissions produced each year and analysing them, both for domestic and international operations, offers a good starting point in contextualising the amount of pollutants that are put into the atmosphere by the industry. Furthermore, the quality of the air surrounding the airport and how it relates to the activity in it can be studied by observing the measured changes in concentration of pollutants over the same timespan. The emissions were estimated using emission factors provided by the European Environmental Agency for the airplanes most commonly used in the European transport fleet for the average LTO cycle. These factors were then combined proportionally to the share of flights a single aircraft made in a region to develop the emission factors for a standard plane from which the total estimates of emissions would be made. After obtaining those results for 2019 and 2020 and for the different destinations of the flights, equivalent CO2 emissions were calculated considering the results of the fuel consumption obtained. The impact the airport’s activity had on the concentration of air quality-related pollutants was asses from data taken from stations in the public network, which has two of them located near the airport. Evaluating the change in concentration of selected pollutants from month to month over the years sampled in the project, and how it mimics the evolution of the changes in operations in the airport over the same month, allows to further understand how air traffic affects air quality. The results of the study show a massive decrease of emissions in 2020, with the equivalent of multiple hundreds of kilotons of CO2 emissions less being emitted that year due to reduction in flights. It is also shown how intercontinental flights cause a disproportionate amount of the total emissions of international flights when accounting for their share of the total flights. In terms of air quality, the area surrounding the airport is found to be not in danger of surpassing the concentration threshold established by European Union regulations for any pollutants and that the levels of those did decrease in 2020 due to a combination of the changes in air traffic and a combination of favourable meteorological factors. With the pandemic still being an ongoing situation, further analysis will need to be made to understand its completes effects and which lessons the transport aviation sector can take from it going forward, as the air transport industry continues to recover and increase its flight volume back to pre-pandemic levels.