Fig 1. Effect modification by vigorous physical activity.

MetS-W: Metabolic syndrome according to World Health Organization. MetS-I: Metabolic syndrome according to International Diabetes Federation. MetS-A: Metabolic syndrome according to Adult Treatment Panel-III criteria. Active defined as vigorous physical activity ≥30 minutes per week. Inactive defined as vigorous physical activity <30minutes per week. Fully adjusted models include age, sex, educational attainment, neighbourhood socio-economic index, occupational exposure to vapours, gases, dusts and fumes, smoking status, smoked pack-years, exposure to passive smoke, consumption of fruits and raw vegetables, and body mass index. PM₁₀: particulate matter <10μm in diameter from all sources. All analyses were done with four-hour fasting participants. Participants’ study area was treated as a random effect in all models. Odds ratio values refer to increments of 10μg/m³ in PM₁₀ exposure. Total N = 3684; N(physically-active) = 2115.