Correlation between indoor air pollution and adult respiratory health in Zunyi City in Southwest China: situation in two different seasons

Table 7 Paired comparison analysis of pulmonary function (FVC, FEV₁, FEV₁/FVC, and PEFR) in 46 adults in winter and summer

Pulmonary function parameters	Asthma-like symptoms and asthma		Z	p value
Pulmonary function parameters	Summer (n = 46)	Winter (n = 46)	Z	p value
FVC in litres (L)	3.5 (2.7–4.1)	2.9 (2.1–3.7)	−5.91^a	< 0.001***
FEV₁ in litres (L)	3.3 (2.4–3.8)	2.7 (1.8–3.5)	−5.91^a	< 0.001***
FEV₁/FVC in percentage	91.7 (87.7–94.0)	91.9 (82.0–94.6)	−2.91^a	< 0.001***
PEFR in litres/min	382.8 (324.9–420.7)	347.9 (303.8–404.4)	−5.89^a	< 0.001***

^aNonparametric test (Wilcoxon signed-rank test); *significant at p < 0.05; *significant at p < 0.05, **significant at p < 0.01, *** significant at p < 0.001