Table 3

Association between annual mean levels of air pollutants and COVID-19 incidence rate by cumulative infection waves in single-pollutant models

Air pollutantFirst waveSecond waveThird wave
RR95% CIRR95% CIRR95% CI
PM2.5 1.0740.978 to 1.1791.0291.002 to 1.0561.0511.027 to 1.075
PM10 1.0640.985 to 1.1491.0231.001 to 1.0451.0401.020 to 1.060
NO2 1.0340.991 to 1.0801.0100.999 to 1.0221.0201.009 to 1.030
NO1.0940.980 to 1.2211.0220.991 to 1.0531.0401.013 to 1.068
O3 0.9740.935 to 1.0160.9900.978 to 1.0010.9800.970 to 0.990
  • Rate ratios (RR) per 1 µg/m3 increase in the annual average exposure to each pollutant estimated from Poisson regression model. Covariates in the model are: age, sex, living in a residential care home, positive history of stroke, treatment for diabetes, antihypertensive treatment and treatment for obstructive airway diseases.

  • First wave from COVID-19 outbreak to 11 June 2020; second wave from COVID-19 outbreak to 31 December 2020; third wave from COVID-19 outbreak to 13 March 2021 (end of observational period).