Relationship between Particulate Matter (PM₁₀) and Airway Inflammation Measured with Exhaled Nitric Oxide Test in Seoul, Korea

Table 2

Correlation analysis of PM₁₀ and FeNO by the Pearson correlation and multivariate linear regression analysis (most correlated time).

PM10 measurement date	PM10 day average	Univariate		Multivariate
		Correlation coefficient	value	B	value
The day of hospital visit	45.88 ± 20.24	0.061	0.016	0.043	0.064
One day before hospital visit	45.74 ± 21.22	0.046	0.067	0.034	0.145
Two days before hospital visit	47.33 ± 25.20	0.057	0.023	0.051	0.026
Three days before hospital visit	47.68 ± 25.06	0.049	0.053	0.040	0.083
Four days before hospital visit	47.88 ± 23.34	0.025	0.312	0.023	0.325

PM₁₀, particulate matter with a diameter of less than 10 μm; FeNO, fractional exhaled nitric oxide. B is the regression coefficient, and the positive sign of regression coefficient means that the variables are positively associated. The multivariate linear regression analysis is adjusted for age, sex, previous history of respiratory disease (asthma, allergic rhinitis, and chronic obstructive pulmonary disease), pulmonary-related medication before the visit (antihistamine, intranasal corticosteroids, inhaled corticosteroids, and leukotriene receptor antagonist), humidity, and temperature. Numbers are presented as the average ± standard deviation.