Table 2 Cumulative relative risk (CRR) and 95% confidence interval of stratified daily incidence of influenza associated with a 10 μg/m³ increase of air pollutants in different temperature layers in Ningbo from 2014 to 2017

O₃

Total

1.028 (1.007,1.050)*

0.936 (0.860,1.018)

1.029 (0.974,1.086)

1.047 (1.001,1.094)*

Gender

 Male

1.038 (1.012,1.065)*

0.975 (0.879,1.083)

1.048 (0.982,1.119)

1.048 (0.991,1.109)

 Female

1.019 (0.993,1.044)

0.900 (0.819,0.989)*

1.009 (0.943,1.079)

1.049 (0.991,1.110)

Age

 0–6

1.017 (0.983,1.051)

0.936 (0.815,1.074)

1.019 (0.934,1.111)

1.001 (0.929,1.079)

 7–17

1.074 (1.008,1.143)*

0.974 (0.832,1.140)

1.203 (1.051,1.378)*

1.008 (0.878,1.158)

 18–64

1.012 (0.988,1.036)

0.933 (0.842,1.034)

0.973 (0.907,1.043)

1.077 (1.017,1.141)*

 ≥ 65

0.995 (0.954,1.039)

0.777 (0.622,0.971)*

0.915 (0.801,1.044)

1.072 (0.963,1.193)

PM_2.5

Total

1.061 (1.004,1.122)*

0.946 (0.833,1.075)

1.109 (0.957,1.285)

1.518 (1.117,2.064)*

Gender

 Male

1.099 (1.027,1.177)*

0.952 (0.814,1.114)

1.098 (0.922,1.309)

2.120 (1.442,3.115)*

 Female

1.024 (0.959,1.094)

0.934 (0.810,1.078)

1.120 (0.935,1.342)

1.117 (0.750,1.666)

Age

 0–6

1.035 (0.945,1.134)

0.892 (0.733,1.086)

1.188 (0.952,1.482)

1.811 (1.067,3.073)*

 7–17

1.064 (0.925,1.223)

0.885 (0.681,1.149)

0.741 (0.467,1.176)

0.730 (0.279,1.910)

 18–64

1.017 (0.951,1.087)

0.980 (0.836,1.149)

1.184 (0.982,1.429)

1.564 (1.053,2.324)*

 ≥ 65

0.982 (0.871,1.107)

0.828 (0.608,1.126)

0.802 (0.583,1.104)

1.564 (0.724.3.382)

PM₁₀

Total

1.043 (1.003,1.085)*

0.956 (0.867,1.053)

1.089 (0.989,1.200)

1.338 (1.052,1.701)*

Gender

 Male

1.071 (1.022,1.124)*

0.954 (0.847,1.074)

1.110 (0.988,1.246)

1.786 (1.321,2.414)*

 Female

1.015 (0.969,1.064)

0.955 (0.856,1.066)

1.069 (0.950,1.204)

1.028 (0.754,1.402)

Age

 0–6

1.026 (0.963,1.093)

0.899 (0.771,1.047)

1.158 (1.000,1.432)*

1.610 (1.067,2.429)*

 7–17

1.062 (0.966,1.168)

0.901 (0.742,1.095)

0.924 (0.689,1.238)

0.908 (0.427,1.934)

 18–64

1.005 (0.958,1.055)

1.015 (0.898,1.148)

1.096 (0.967,1.241)

1.351 (0.994,1.837)

 ≥ 65

0.986 (0.906,1.074)

0.854 (0.669,1.090)

0.853 (0.690,1.056)

1.255 (0.687,2.291)

NO₂

Total

1.118 (1.028,1.216)*

0.850 (0.673,1.073)

1.434 (1.161,1.771)*

1.933 (1.230,3.038)*

Gender

 Male

1.143 (1.032,1.266)*

0.882 (0.658,1.183)

1.281 (0.988,1.659)

2.130 (1.206,3.764)*

 Female

1.093 (0.989,1.209)

0.817 (0.625,1.070)

1.611 (1.244,2.087)*

1.782 (0.981,3.236)

Age

 0–6

1.101 (0.961,1.261)

0.676 (0.464,0.987)*

1.404 (1.017,1.941)*

1.566 (0.742,3.307)

 7–17

1.335 (1.087,1.639)*

0.605 (0.357,1.025)

1.402 (0.747,2.628)

0.949 (0.206,4.375)

 18–64

1.065 (0.964,1.176)

1.221 (0.901,1.654)

1.522 (1.159,1.998)*

2.132 (1.160,3.918)*

 ≥ 65

1.026 (0.863,1.220)

0.848 (0.456,1.575)

1.073 (0.650,1.771)

3.121 (0.969,10.052)