Table 1 shows the associations (Spearman's rho) between noise and air pollution exposure across all postcodes in London. Due to the small observed temporal variation, we report correlations between the median of metrics across all years. Correlations were very strong between the different noise metrics (r > 0.99) and between the different air pollutants (r > | 0.94 |); correlations with ozone were negative, as expected, due to it being generally elevated in background locations whereas other pollutants are mostly elevated close to source. We observed very similar patterns in correlations between the different noise and air pollutants, the magnitude of these correlations changes marginally between most traffic-related and background pollutants. PM10traffic and PM2.5traffic had the strongest correlations with any of the noise metrics (r = 0.51–0.55 and r = 0.49–0.53, respectively); PM2.5 the weakest (r = 0.39–0.42), apart from ozone. Pearson's correlations were marginally higher than Spearman's correlations (see Supplemental Table S2 and Supplemental Fig.S3).