Inclusion criteria

Exclusion criteria

Ÿ Original articles

Ÿ Epidemiological or observational studies such as cross-sectional, cohort, or case-control studies

Ÿ Only human studies

Ÿ Articles published in English, French

Ÿ Focus on traffic related air pollution

Ÿ Focus on population working or living along a major/trunk road

Ÿ Studies had reported clearly at least one of the exposure variables related to TRAP

Ÿ Studies had reported respiratory symptoms or respiratory diseases

Ÿ Studies examined the association between traffic related air pollution (TRAP) and development of respiratory symptoms or respiratory diseases

Ÿ Non-research studies, off-topic studies, studies concerning populations not exclusively exposed to traffic-related air pollution

Ÿ Review, commentaries

Ÿ Animal studies

Ÿ Abstract or full articles not available

Ÿ Studies about TRAP but not on major/trunk road

Ÿ Studies that measured exclusively pollution exposure to non-traffic related air pollution