Table 3.

Association between air pollutants and primary care visits at night due to asthma attack (single pollutant model)

Air pollutants	Unit increment	Concentration on the day of the PCV			Concentration on the day before the PCV			3-Day mean concentration before the PCV
		OR	95 % CI		OR	95 % CI		OR	95 % CI
PM2.5	10 μg/m3	1.241	0.938	1.643	0.972	0.725	1.303	1.219	0.744	1.998
PM10	10 μg/m3	1.120	0.953	1.315	1.067	0.881	1.292	1.220	0.915	1.625
OBC	0.1 μg/m3	1.062	0.977	1.153	0.978	0.905	1.057	1.028	0.904	1.168
NO2	10 ppb	2.083	1.092	3.976	0.829	0.469	1.464	1.267	0.514	3.118
Ozone	10 ppb	0.838	0.512	1.370	1.615*	1.037	2.514	2.603*	1.068	6.344

Associations are shown as the odds ratio (OR) and their 95 % confidence interval (CI) per unit increment of each pollutant. Values have been adjusted for daily mean atmospheric pressure, relative humidity, temperature, wind speed, and hours of daylight

PVC primary care visit

* p < 0.05