Table 5

Associations between air pollutants and PCVs at night due to asthma attack (multipollutant model)

	Unit increment	April until June (spring)			July and August (summer)			September until November (fall)			December until March (winter)			Annual effects
	Unit increment	OR	95% CI		OR	95% CI		OR	95% CI		OR	95% CI		OR	95% CI
Concentration on the same day as a primary care visit
PM_2.5	10 μg/m³	0.936	0.843	1.039	0.891	0.743	1.067	0.962	0.863	1.074	1.081	0.939	1.245	0.977	0.920	1.036
NO₂	10 ppb	0.990	0.709	1.383	0.980	0.528	1.820	1.252	0.861	1.821	0.722	0.414	1.258	1.028	0.858	1.230
Ozone	10 ppb	1.025	0.888	1.184	1.130	0.967	1.321	1.031	0.841	1.263	0.864	0.585	1.277	1.065	0.981	1.157
Atmospheric pressure	1 hPa	1.027*	1.002	1.053	0.995	0.959	1.032	1.012	0.984	1.041	1.002	0.968	1.038	1.016*	1.002	1.031
Temperature	1°C	1.095*	1.043	1.150	1.229*	1.057	1.430	0.996	0.958	1.034	0.997	0.935	1.062	1.030*	1.004	1.056
Relative humidity	10%	0.979	0.823	1.165	1.226	0.816	1.843	0.834	0.678	1.025	0.956	0.748	1.221	0.960	0.864	1.066
Wind speed	1 m/s	0.892	0.738	1.077	0.786	0.609	1.014	0.923	0.777	1.095	0.863	0.677	1.099	0.904*	0.821	0.996
Hours of daylight	1 h	0.971	0.935	1.009	0.994	0.928	1.066	0.953*	0.916	0.991	1.002	0.948	1.059	0.979	0.957	1.000
Concentration on the day before a primary care visit
PM_2.5	10 μg/m³	0.949	0.850	1.059	1.172	0.982	1.399	0.957	0.861	1.064	1.157*	1.006	1.331	1.017	0.958	1.079
NO₂	10 ppb	1.161	0.832	1.619	0.760	0.378	1.530	1.173	0.799	1.722	0.857	0.487	1.509	0.979	0.813	1.179
Ozone	10 ppb	1.168*	1.011	1.349	1.087	0.929	1.272	0.977	0.798	1.197	1.216	0.809	1.827	1.115*	1.025	1.212
Atmospheric pressure	1 hPa	1.026*	1.000	1.054	1.021	0.985	1.058	0.998	0.971	1.025	1.034	0.999	1.070	1.018*	1.003	1.032
Temperature	1°C	1.102*	1.050	1.157	1.081	0.922	1.268	0.980	0.943	1.019	0.971	0.913	1.033	1.017	0.992	1.043
Relative humidity	10%	1.009	0.843	1.207	1.035	0.691	1.551	0.854	0.702	1.040	1.139	0.891	1.458	0.987	0.889	1.097
Wind speed	1 m/s	0.965	0.805	1.157	1.000	0.795	1.257	0.925	0.781	1.095	1.123	0.897	1.407	0.986	0.899	1.081
Hours of daylight	1 h	0.993	0.956	1.032	0.987	0.924	1.056	0.990	0.951	1.032	0.983	0.930	1.040	0.993	0.971	1.016
3-day mean concentration before a primary care visit
PM_2.5	10 μg/m³	0.952	0.824	1.101	1.128	0.877	1.451	0.916	0.803	1.046	1.146	0.953	1.377	0.988	0.916	1.065
NO₂	10 ppb	1.036	0.680	1.578	0.584	0.200	1.708	1.166	0.715	1.902	0.665	0.329	1.345	0.897	0.708	1.138
Ozone	10 ppb	1.209*	1.001	1.460	1.123	0.896	1.407	0.989	0.752	1.300	1.249	0.733	2.130	1.158*	1.039	1.290
Atmospheric pressure	1 hPa	1.024	0.993	1.057	1.020	0.974	1.069	0.998	0.964	1.033	1.026	0.978	1.076	1.017	1.000	1.035
Temperature	1°C	1.121*	1.061	1.185	1.065	0.882	1.287	0.988	0.946	1.030	1.010	0.937	1.090	1.036*	1.007	1.065
Relative humidity	10%	0.953	0.752	1.209	1.167	0.688	1.979	0.743*	0.562	0.981	1.155	0.782	1.704	0.955	0.826	1.105
Wind speed	1 m/s	0.936	0.722	1.214	0.903	0.609	1.337	0.804	0.622	1.039	1.001	0.665	1.508	0.907	0.789	1.042
Hours of daylight	1 h	0.986	0.928	1.049	1.034	0.932	1.147	0.942*	0.888	0.998	0.972	0.889	1.063	0.979	0.947	1.013

A multipollutant model is a model which simultaneously assessed the associations between PCVs at night due to asthma attack and increment of PM_2.5, NO₂ and ozone.
Associations are shown as ORs and their 95% CIs per unit increment of each parameter.
*p<0.05.
NO₂, nitrogen dioxide; PCV, primary care visit; PM, particulate matter.