8. Comparing air quality

Air quality can be better or worse in different streets within the same city, and can change rapidly according to the time of day. This depends on road traffic and on other sources of air pollutants (e.g. industrial areas). In this lesson, we explore the air quality index (AQI) in the city of Barcelona, Spain, shown at two different times on the same day. In the map, you will see how the air quality changes according to the time of day and the part of the city.