To quantify health effects of synergizing chemical and biological pollutants in a targeted population setting, i.e., school-aged children. Indoor air pollutants will be monitored within the classrooms with high end sensors. Exposure data from additional sources (outdoor, home, transports) will be obtained. Health outcomes will be assessed prospectively using validated medical procedures and real-time tracking with mobile health (mHealth) equipment and a gamified computer app.

Communication with individual schools and families representing diverse cultural and socioeconomic backgrounds, will be conducted and formal participation consents obtained. The target population will include healthy children and be enriched for children with respiratory allergies and asthma. Provision of instructions, training for participation and baseline assessments of respiratory, immune, and mental health using questionnaires and relevant physiological measurements (e.g spirometry, FeNO), will be performed. Sensors will be positioned and cross-checked for functionality.Health data from the cohort will be monitored by a specifically designed gamified application, as well as by state-of-the-art wearable tracking technology. The app will capture input from the participants at large, while the trackers will accurately, continuously, and remotely, identify personalized patterns of all day activity status, heart rate, oxygen saturation, temperature, blood pressure, sleep, respiratory rate, and mechano-acoustic breathing sounds signatures. Sentinel data will be processed in Work Package 6 and integrated in the SynAir-G autonomous sensing platform.

Children will be prospectively followed-up for a school year. Investigators will regularly visit schools to keep sensors running and collect materials. Real-time tracking will be coupled with regular communication and face-to-face visits for health outcome assessments. Devices will be positioned in selected locations. The cohort will also provide the setting for establishing indoor and outdoor interactions, dose-responses in real life, and health outcome data for integration and synergy analyses.

Inclusion Criteria:

1. Students of primary schools aged 8-9 years.
2. The subject and/or legal custodian have the verbal, writing and mental ability to understand the intent and character of the study.
3. Written informed consent from the child's parents/guardian's

Exclusion Criteria:

Unwilling to use the application and follow the procedures of the protocol

Children at this age have the ability to understand the character of the study, to handle the app and the wearables, to successfully perform lung function and airway inflammation measurements (as it has been ascertained in the previous FP7_PreDicta and Horizon_CURE projects), to cooperate with blood sampling, while not being yet subjective to hormonal changes of puberty. Moreover, students at this age mainly attend lessons in the same class, thus exposures in the school environment are considered stable,