Previous work done by this team (Moreno et al., 2015 - Environmental Research 142: 495-510) have shown that the study of air quality during a trip in various means of transport depends on several physical-chemical parameters that are independent of each other since they are linked to different sources and processes. In the case of urban transport buses, our studies so far have shown that a significant part of the air pollutants inside the vehicle are due to self-contamination, that is, emissions produced by the bus itself. However, it is also clear that there is a combination of factors affecting air quality in the bus, especially the opening / closing of windows and doors (and the infiltration of outside air), the starting or idling of the bus, the type of driving, the topography of the city and the route, and the technology used for its operation.
New technical improvements in monitoring equipment are producing increasingly sophisticated instruments that are becoming more portable, making it practical for an individual to monitor a range of different air quality parameters (PM sizes and number, various gases) simultaneously while moving through the city. This opens up the possibility of recording much more accurately the actual real-time dose of air pollutants inhaled daily by regular commuters. Our starting hypothesis is that the quality of the air we breathe while commuting by public bus will vary greatly according on the type of fuel and post-combustion treatment (e.g. SCRT filters) technology, route chosen, location inside the bus, infiltration of outdoor air, age of the bus, and seasonal variations influencing ventilation and air conditioning operating conditions.
The primary objective of this project is to significantly improve our understanding of what controls air quality inside public buses, identifying the effect of each variable to allow us to elaborate a protocol of best practice regarding air quality while commuting in this transport mode.