Tracking the association between metro-railway construction works and PM levels in an urban Mediterranean environment

Metro-railways are considered to be a sustainable means of public transportation, as they contribute substantially to the reduction of air pollutant emissions through the decrease in the number of cars and heavy vehicles circulating in the road network. However, the works related to their construction may pose an extra burden in air quality status and consequently in public health. In the present study, we studied the possible effects of the metro-railway construction works in Thessaloniki, Greece, on public health through 2 well-established air quality indices, namely the PI and DAQI. The analysis suggested that there were excess high levels of PM10 measured in the close vicinity of the construction-sites during the period studied (2008-2014). These concentrations are likely to have originated from local construction sources rather than transport or continental secondary dust sources and might have an adverse health impact, as according to the PI index, the majority of days in the construction sites were grouped as "low pollution" or "moderate pollution", while a small percentage of days (1.84%) were suggested to be unhealthy for the most vulnerable groups of the population. Similarly, the DAQI index revealed that the vast majority of days were grouped as "poor" air quality, while 5.50% of the days reflected the most oppressive conditions for public health, as they were characterized as "very poor" air quality. Given the need of reaching a compromise between future transportation sustainability and public health during the construction works, the feasibility of appropriate measures in the area should be examined.