Table 4 Extreme influence analysis of different air pollution factors from 2008 to 2014 using two-pollutant models. Relative risk (RR) and 95% confidence interval (CI) were used to estimate the cumulative influence of air pollution factors in total IS cases

0.98 (0.87,1.10)

0.99 (0.87,1.13)

1.00 (0.86,1.16)

0.99 (0.85,1.17)

0.99 (0.84,1.17)

0.98 (0.82,1.17)

1.14 (0.98,1.32)

1.29 (1.09,1.52)

1.42 (1.18,1.71)

1.50 (1.22,1.84)

1.50 (1.21,1.86)

1.48 (1.17,1.87)

0.88 (0.77,1.00)

0.87 (0.75,1.01)

0.86 (0.73,1.03)

0.86 (0.71,1.04)

0.85 (0.70,1.04)

0.85 (0.68,1.05)

1.32 (1.13,1.54)

1.36 (1.14,1.62)

1.37 (1.13,1.67)

1.37 (1.10,1.70)

1.36 (1.08,1.71)

1.34 (1.05,1.72)

0.81 (0.71,0.92)

0.79 (0.68,0.92)

0.79 (0.66,0.94)

0.81 (0.67,0.97)

0.82 (0.67,1.00)

0.84 (0.68,1.04)

1.09 (0.95,1.26)

1.17 (1.00,1.37)

1.24 (1.04,1.47)

1.26 (1.04,1.53)

1.25 (1.02,1.54)

1.23 (0.98,1.53)

1.13 (0.97,1.32)

1.17 (0.99,1.38)

1.21 (1.00,1.45)

1.24 (1.02,1.52)

1.27 (1.03,1.56)

1.29 (1.03,1.61)

1.07 (0.94,1.22)

1.11 (0.96,1.28)

1.15 (0.99,1.35)

1.20 (1.01,1.42)

1.22 (1.03,1.45)

1.25 (1.04,1.49)