Bernatsky et al. reported the association between PM2.5 exposure and the odds of prevalent SARDs in case-control studies performed in Quebec and Alberta, Canada . Exposure measurement was determined using average residential exposures at diagnosis based on satellite-derived data. In Alberta, a nonlinear association was found. The OR at PM2.5 exposures of 6.02 to 6.92 μg/m3 was 1.25 (95% Credible Interval (CrI): 1.15 to 1.36), the OR at exposures of 6.92 to 8.11 μg/m3 was 1.03 (95% CrI: 0.94 to 1.13), and the OR at exposures of ≥8.12 μg/m3 was 1.13 (95% CrI: 1.02 to 1.25) after adjustment for sex, age, urban versus rural residence, and median income. In Quebec, increasing odds for increasing levels of PM2.5 exposure were demonstrated, with significant odds at levels of ≥11.81 μg/m3. In a study focused on one city in Alberta (Calgary) using land use regression models, exposure to PM2.5 appeared to be potentially associated with prevalent SARD (OR: 1.10; 95% CrI: 1.01 to 1.22) in the model adjusted for sex, mean income, age > 45 years, and interaction between age and sex . No association with NO2 was demonstrated (OR: 1.02; 95% CrI: 0.98 to 1.02) .