Barking up the Right Tree: Using Tree Bark to Track Airborne Particles in School Environment and Link Science to Society.

Children's exposure to air pollution affects both their health and learning skills. Fine and ultrafine particulate matter (PM2.5, PM1), notably issued from traffic sources in urban centers, belong to the most potential harmful health hazards. However their monitoring and the society's awareness on their dangers need to be consolidated. In this study, raising teacher and pupil involvement for air quality improvement in their schools environment is reached through developing a passive monitoring technique (bio-sensors made of tree bark). The experiment was implemented in two urban elementary schools situated close to a main traffic road of the city of Toulouse (South of France). Magnetic properties, carbonaceous fraction measurements, and scanning electronic microscopy (SEM-EDX) investigations were realized both on passive bio-sensors and filters issued from active sampling. We find that traffic is the main PM1 source for both outdoors and indoors at schools. Higher levels of outdoor PM in the school's environments compared to urban background are reached especially in the cold period. The schools proximity to a main traffic source and lack of ventilation are the main causes for observed PM1 accumulation in classrooms. The co-working experiment with educational teams and pupils shows that the use of bio-sensors is a driver for children empowerment to air pollution and therefore represents a potential key tool for the teachers though limiting eco-anxiety. As PM accumulation is observed in many scholar environments across Europe, the proposed methodology is a step toward a better assessment of PM impact on pupil's health and learning skills.

Comparison of microclimate measurements and perceptions as part of a global evaluation of environmental quality at neighbourhood scale.

The EUREQUA project raises the issue of the definition and evaluation of the environmental quality of neighbourhoods. The approach consists of integrating and cross-referencing observable data characterising the physical environment and people's perception of their quality of life. The study area is a neighbourhood in Toulouse (France) with high social and typo-morphological diversity, subject to noise and air pollution nuisances. Three 3-day field campaigns were organised in January, April, and June 2014. Instrumented and commented walks took place three times per day. For each one, measurements of physical environmental parameters and surveys were performed simultaneously at six locations in the neighbourhood. The study focuses on microclimate and thermal comfort issues. It aims to compare in situ meteorological data of air temperature, humidity, wind speed, and mean radiant temperature, with quantitative results rating human perception of heat, humidity, wind, and thermal comfort. The variability in perception and measurements is mainly driven by seasonal effects, especially for heat and humidity, and, to a lesser extent, for wind. Wind perception and measurement also vary spatially, thus highlighting site effects. Linear models indicate a positive link between heat perception and mean radiant temperature, as well as between wind perception and mean and standard deviation of wind speed (with a higher sensitivity of people to wind under winter climate conditions). Finally, it is found that perception of thermal comfort is only slightly linked to the different microclimate dimensions, and is rather driven by other appreciation factors and emotional criteria related to the general environmental quality of the study area.