Figure 1.

Map of air pollution (${\mathrm{NO}}_2$, ${\mathrm{NO}}_{\mathrm{x}}$, ${\mathrm{PM}}_{2.5}$, ${\mathrm{PM}}_{2.5–10}$, and ${\mathrm{PM}}_{10}$) of areas where participants lived in 2010 and map of incident RA scatter distribution. The administrative boundary data of the UK are sourced from UK Government Open Data portal (https://data.gov.uk/dataset/3fd8d2d2-b591-42ff-b333-c53a6a513e96/countries-december-2017-full-clipped-boundaries-in-great-britain). These data are UK government–released open data. (A) ${\mathrm{NO}}_2$, (B) ${\mathrm{NO}}_{\mathrm{x}}$, (C) ${\mathrm{PM}}_{2.5}$, (D) ${\mathrm{PM}}_{2.5–10}$, (E) ${\mathrm{PM}}_{10}$, and (F) incident RA. Note: ${\mathrm{NO}}_2$, nitrogen dioxide; ${\mathrm{NO}}_{\mathrm{x}}$, nitrogen oxides; ${\mathrm{PM}}_{2.5}$, particulate matter with aerodynamic diameter $\le 2.5\mathrm{\mu }\mathrm{m}$; ${\mathrm{PM}}_{2.5–10}$, particulate matter with aerodynamic diameter $2.5–10\mathrm{\mu }\mathrm{m}$; ${\mathrm{PM}}_{10}$, particulate matter with aerodynamic diameter $\le 10\mathrm{\mu }\mathrm{m}$; RA, rheumatoid arthritis.