Study of Indoor Air Pollutants and Their Impact in Children's Health and Wellbeing

Inclusion Criteria: * Child included in the SynAir-G observational study * Child and caregiver(s) willing to follow the study procedures * Written informed consent from the child's parents/guardians * For case group, at least one positive answer (yes) to any of the following questions and for control group, negative answers to all the following questions based on the baseline questionnaire administered in the SynAir-G observational study, as shown below.: a. General health i. Does your child have any health problems (if yes to asthma, allergic rhinitis /rhino-conjunctivitis, atopic dermatitis)? b. Asthma i. Has your child ever had wheezing or whistling in the chest in the past 12 months? ii. In the past 12 months, has your child's chest sounded wheezy during or after exercise? iii. In the past 12 months, has your child had a dry cough at night, apart from a cough associated with a cold or chest infection? c. Rhinitis i. In the past 12 months has your child had a problem with sneezing, or a runny, or blocked nose when she/he DID NOT have a cold or the flu? d. Eczema (both answers yes) i. Has your child had this itchy rash at any time in the past 12 months? If so, has this itchy rash at any time affected any of the following places: the folds of the elbows, behind the knees, in front of the ankles, under the buttocks, or around the neck, ears or eyes? e. Food allergy i. Has your child had diagnosed food allergy during last 12 months? * For case group: Diagnosis of asthma/allergic rhinitis/eczema/food allergy (based on SYNAIR-G baseline questionnaire), active during the past year. * For control group: absence of diagnosis of asthma/allergic rhinitis/eczema/food allergy (based on SYNAIR-G baseline questionnaire) Exclusion Criteria: * Child or child's parents/guardians who: 1. Refuse to participate in the project / to give informed consent. 2. Do not want to follow the protocol procedures. 3. Do not read or/and write in French. 4. Plan a long stay outside the region that does not allow them to follow the visit plan. 5. The child is not affiliated to the French social security service