Accumulation and Diffusion of PM from Outdoor to Indoor by Clothing under Haze Conditions: A Case Study of Zhengzhou, China

Table 4

The number of air changes .

Pollution levels	Fabric type	Exposure time
Moderate pollution	Polyester	1 h	0.189	0.157	0.1730
		2 h	0.287	0.303	0.2950
		3 h	0.486	0.461	0.4735
	Polyester and cotton	1 h	0.243	0.239	0.2410
		2 h	0.349	0.381	0.3650
		3 h	0.232	0.247	0.2395
	Cotton	1 h	0.402	0.411	0.4065
		2 h	0.177	0.204	0.1905
		3 h	0.459	0.465	0.4620
Heavy pollution	Polyester	1 h	0.279	0.282	0.2805
		2 h	0.179	0.179	0.1790
		3 h	0.298	0.271	0.2845
	Polyester and cotton	1 h	0.260	0.237	0.2485
		2 h	0.246	0.242	0.2440
		3 h	0.275	0.253	0.2640
	Cotton	1 h	0.561	0.623	0.5920
		2 h	0.174	0.179	0.1765
		3 h	0.649	0.644	0.6465