Ozone Pollution and Acute Exacerbation of Asthma in Residents of China: An Ecological Study

Figures & data

Figure 1 The geographical location of hospitals (red circles denote public hospitals) and air quality monitoring stations (blue circles denote air quality monitoring station) in Shijiazhuang.

Table 1 Descriptive Statistics on Asthma Cases, Air Pollutants, Meteorological Factors in Shijiazhuang During 2010–2016

	Mean±SD	Min	25th	50th	75th	Max
Asthma hospitalizations	3.00±2.22	0	1	2	4	13
Air pollutants
O3 (μg/m^3)	90.8±56.4	3	45	80	128	359
NO2 (μg/m^3)	60.3±27.6	9	42	57	75	181
SO2 (μg/m^3)	73.3±68.1	3	32	53	93	515
CO (μg/m^3)	2.08±1.87	0.1	1.1	1.7	2.7	18.4
PM2.5(μg/m^3)	106.9±88.9	5	53	86	132	750
PM10(μg/m^3)	185.3±101.4	15	104	157	228	807
Meteorological factors
Temperature (%)	13.2±10.5	−18.4	2.6	14.8	23.7	35.5
Relative humidity (%)	60.9±.21.2	12	47	63	76	99

Abbreviations: SD, the standard deviation; Min, the minimum of the variables; Max, the maximum of the variables.

Figure 2 The time-series distributions of the daily asthma exacerbation cases and O₃ in Shijiazhuang, China from 2010 to 2016.

Figure 3 Coefficients of Spearman correlation between asthma exacerbation cases and air pollutants and meteorological factors in Shijiazhuang, China from 2010 to 2016. (Y-axis: the cases of asthma, concentration of pollution, relative humidity and temperature. X-axis: the same with the Y-axis).

Figure 4 Relationship between air pollutants, meteorological variables and asthma exacerbation cases (Y-axis: the predicted value of asthma cases as the independent variables changed. X-axis: the distribution of variables (including ozone, other air pollutants, temperature, humidity and time) in the asthma patients).

Table 2 Relative Risks with 95% CI of Asthma Exacerbations in Shijiazhuang During 2010–2016 Based on 10 μg/m³ Increases in the Fine Particulate Matter (O₃) Concentration

	Lag Effect			Cumulative Effect
	RR	95% CI		RR	95% CI
Lag 0	1.022	0.995–1.048	Lag 0	1.022	0.995–1.048
Lag 1	1.013	1.000–1.026*	Lag 0–1	1.035	0.999–1.072
Lag 2	1.009	0.996–1.022	Lag 0–2	1.045	1.006–1.085*
Lag 3	1.009	0.996–1.022	Lag 0–3	1.054	1.012–1.098*
Lag 4	1.010	0.999–1.021	Lag 0–4	1.065	1.019–1.112*
Lag 5	1.012	1.002–1.022*	Lag 0–5	1.078	1.030–1.127*
Lag 6	1.013	1.003–1.024*	Lag 0–6	1.092	1.043–1.144*
Lag 7	1.019	1.008–1.030*	Lag 0–7	1.108	1.056–1.163*
Lag 8	1.014	1.004–1.025*	Lag 0–8	1.124	1.068–1.181*
Lag 9	1.013	1.003–1.023*	Lag 0–9	1.139	1.081–1.199*
Lag 10	1.011	1.000–1.022*	Lag 0–10	1.152	1.093–1.213*
Lag 11	1.008	0.996–1.022	Lag 0–11	1.162	1.102–1.225*
Lag 12	1.007	0.994–1.020	Lag 0–12	1.170	1.108–1.236*
Lag 13	1.006	0.995–1.019	Lag 0–13	1.178	1.117–1.243*
Lag 14	1.009	0.984–1.035	Lag 0–14	1.189	1.128–1.254*

Note: *p<0.05.

Figure 5 The interaction of O₃ and SO₂, NO₂, temperature as well as relative humidity on asthma exacerbation cases at present day in Shijiazhuang, China from 2010 to 2016, the interaction of O₃ with SO₂ (top left); the interaction of O₃ with NO₂ (top right); the interaction of O₃ with temperature (bottom left); the interaction of O₃ with relative humidity (top right).

Figure 6 The result of model diagnostic of PDLM on 14-day lag.