Table 1.

Search terms used to identify articles in MEDLINE.

Category	Search terms
Respiratory health	MeSH terms: Asthma OR Bronchitis OR Cough OR Forced Expiratory Volume OR Pulmonary Ventilation OR Respiratory Sounds OR Rhinitis OR Respiratory Disorders OR Spirometry OR Vital Capacity Free text: airway* OR asthma* OR breath* OR bronchi* OR cough* OR exacerbation* OR hayfever OR hay fever OR lung OR pulmonary OR respiratory OR rhinoc* OR wheez*
Outdoor allergens	MeSH terms: Allergens OR Alternaria OR Cladosporium OR Fungi OR Pollen OR Spores, Fungal Free text: aeroallergen* OR aero allergen or aero allergens OR allergen* OR aspergillus OR cedar OR OR grass OR birch OR pollen* OR mould* OR mold* OR parietaria OR ragweed OR spore*
Air pollution	MeSH terms: Air Pollution OR Air Pollutants OR Ozone OR Nitrogen Dioxide OR Particulate Matter OR Sulfur Dioxide OR Traffic-Related Pollution OR Vehicle Emissions Free text: air quality OR carbon monoxide OR emission* OR exhaust OR freeway* OR highway* OR motorway* OR nitrogen dioxide OR particulat* OR particle* OR pollut* OR road* OR sulphur dioxide OR traffic* OR ozone
Study design	MeSH terms: Case-Control Studies OR Cross-Over Studies OR Cohort Studies OR Longitudinal Studies Free text: case control OR casecontrol OR case crossover OR cohort OR daily OR longitudinal OR panel OR timeseries OR time series