. 2019 Dec 31;16(12):e1003010. doi: 10.1371/journal.pmed.1003010

Table 2. Spearman correlation coefficients among the environmental variables in 184 Chinese cities, 2014–2017.

Variables	PM_2.5	PM₁₀	SO₂	NO₂	CO	O₃	Temp	RH
PM_2.5	1.00	0.90^*	0.56^*	0.64^*	0.61^*	−0.02 (P = 0.452)	−0.26^*	−0.08^*
PM₁₀	―	1.00	0.59^*	0.64^*	0.57^*	0.05 (P = 0.215)	−0.26^*	−0.28^*
SO₂	―	―	1.00	0.55^*	0.52^*	−0.09^*	−0.38^*	−0.33^*
NO₂	―	―	―	1.00	0.54^*	−0.13^*	−0.31^*	−0.12^*
CO	―	―	―	―	1.00	−0.21^*	−0.28^*	−0.04^*
O₃	―	―	―	―	―	1.00	0.53^*	−0.23^*
Temp	―	―	―	―	―	―	1.00	0.26^*
RH	―	―	―	―	―	―	―	1.00

*P < 0.001.

Abbreviations: PM_2.5, particulate matter ≤2.5 μm in aerodynamic diameter; PM₁₀, particulate matter ≤10 μm in aerodynamic diameter; RH, relative humidity; Temp, temperature