Table 3. Multiple regression analyses of changes in children’s lung function associated with ADD of PM_2.5¹.

Lung function	Crude model			Main model2			Model I3			Model II4
	β5 (95% CI)	P value		β (95% CI)	P value		β (95% CI)	P value		β (95% CI)	P value
FVC (mL)	−27.08 (−32.41, −21.75)	<0.0001		−14.87 (−22.86, -6.88)	0.0003		−12.06 (−21.15, −2.97)	0.0096		−10.49 (−20.47, −0.50)	0.0402
FEV1 (mL)	−23.65 (−28.30, −19.00)	<0.0001		−10.02 (−16.79, −3.25)	0.0039		−8.52 (−16.10, −0.94)	0.0281		−7.68 (−15.80, −0.44)	0.0386
PEF (mL/s)	−31.16 (−44.04, −18.28)	<0.0001		−0.90 (−22.94, 21.13)	0.9361		3.96 (−20.18, 28.11)	0.7478		2.74 (−23.66, 29.13)	0.8391
FEV1/FVC (%)	0.07 (−0.04, 0.18)	0.1885		0.23 (0.02, 0.44)	0.0355		0.19 (−0.05, 0.42)	0.1231		0.14 (−0.13, 0.40)	0.3105

¹, table data: β (95% CI) P value, result variable: lung function variables, exposure variable: ADD of PM_2.5, µg/kg-d; ², main model adjust for: age, gender, weight, height; ³, model I adjust for: +Parental smoking, Sleep in own bed/room, Kitchen style, Cook fuel, Ventilation use, Heat in winter, Heat fuel, Air purifier, Keep pets, Mold, Air fresher, Parents` education and occupation, Children recent respiratory infections, Parental history of asthma, Pre-birth and Breast feeding; ⁴, model II adjust for: +Exercise-related variables: Sports activities, and Sweat after sports activities, and Nutrition-related variables: fruit, vegetable, dairy, high fat and high calorie products and fish intake frequency; ⁵, β, the estimated changes of lung function associated with ADD of PM_2.5; CI, confidence interval.