Table 2.

Descriptive statistics of pollutants and correlation matrix among participants with IBD in the UK Biobank Study, 2006–2010.

Air pollutants (${\mathrm{\mu }\mathrm{g}/\mathrm{m}}^3$)	$\text{Mean}\pm \text{SD}$	Median (IQR)	Min and Max	Pearson correlation coefficients
				${\mathrm{NO}}_{\mathrm{x}}$	${\mathrm{NO}}_2$	${\mathrm{PM}}_{10}$	${\mathrm{PM}}_{2.5}$
${\mathrm{NO}}_{\mathrm{x}}$	43.9 (15.2)	42.0 (34.8, 50.4)	19.7, 247.5	1	0.789	0.672	0.864
${\mathrm{NO}}_2$	29.0 (8.9)	27.9 (23.0, 33.4)	10.0, 86.6	0.789	1	0.792	0.736
${\mathrm{PM}}_{10}$	19.3 (1.9)	19.1 (18.0, 20.3)	13.7, 28.6	0.672	0.792	1	0.652
${\mathrm{PM}}_{2.5}$	10.0 (1.1)	9.9 (9.3, 10.6)	8.2, 20.7	0.864	0.736	0.652	1

Note: IBD, inflammatory bowel disease; IQR, interquartile range; max, maximum; min, minimum; ${\mathrm{NO}}_2$, nitrogen dioxide; ${\mathrm{NO}}_{\mathrm{x}}$, nitrogen oxides; PM, particulate matter; ${\mathrm{PM}}_{2.5}$ PM with aerodynamic diameter $\le 2.5\mathrm{\mu }\mathrm{m}$; ${\mathrm{PM}}_{10}$, PM with aerodynamic diameter $\le 10\mathrm{\mu }\mathrm{m}$; SD, standard deviation.