Association between short-term exposure to air pollution and ischemic stroke onset: a time-stratified case-crossover analysis using a distributed lag nonlinear model in Shenzhen, China

Table 3 Spearman correlation coefficients among air pollution and meteorological factors in Shenzhen from 2008 to 2014

Variables	SO₂	NO₂	PM₁₀	O₃	CO	Temperature	Relative humidity
SO₂	1.0000	0.6344	0.7017	0.1404	0.4063	−0.2481	−0.4962
NO₂	0.6344	1.0000	0.7008	0.0685	0.2926	−0.3123	−0.2382
PM₁₀	0.7017	0.7008	1.0000	0.4623	0.3485	−0.3225	− 0.5461
O₃	0.1404	0.0685	0.4623	1.0000	−0.0101	− 0.0380	− 0.4165
CO	0.4063	0.2926	0.3485	−0.0101	1.0000	−0.3223	− 0.2073
Temperature	−0.2481	− 0.3123	− 0.3225	−0.0380	− 0.3223	1.0000	0.3078
Relative humidity	−0.4962	−0.2382	− 0.5461	−0.4165	− 0.2073	0.3078	1.0000

Note: SO₂ sulfur dioxide; NO₂ nitrogen dioxide; PM₁₀ particulate matter less than 10 μm in aerodynamic diameter; CO carbon monoxide; O₃ ozone

ISSN: 1476-069X