Table 3.

Parameters of typical confined space scenarios.

Scenario	Number of seats	Length (m)	Width (m)	Social distance, d (m)	Distance index, Pd	Pd with 50% occupancy ratio	Ventilation rate with clean air, Q/N(m3/h∙p)	Air distribution form	Ventilation index, Ez	$\frac{{\text{P}}_{\text{d}}}{{\text{E}}_{\text{z}}\text{∙Q/N}}\text{(50\%)}$
Long bus (GB9673-1996, 1996GB9673-, 1996GB9673-1996, 1996)	69	13.7	2.55	0.72	49.3 %	36.7 %	20	Ceiling supply, floor return	1	0.025 (0.018)
Air cabin (GB9673-1996, 1996GB9673-, 1996GB9673-1996, 1996)	350	–	–	0.78	48.0 %	35.2 %	25	Ceiling supply, floor return	1	0.019 (0.014)
Public bus (GB9673-1996, 1996GB9673-, 1996GB9673-1996, 1996)	75	8.5	2.5	0.35	62.2 %	49.6 %	15	Ceiling supply, ceiling return	0.8	0.052 (0.041)
Subway (GB50157—2003, 2013GB50157—, 2013GB50157—2003, 2013)	200	22	3	0.57	53.4 %	40.8 %	20	Ceiling supply, ceiling return	0.8	0.033 (0.026)
High-speed train (TB10621-2009, 2009TB10621-, 2009TB10621-2009, 2009)	85	25	3.3	0.99	43.5 %	30.9 %	20	Ceiling supply, floor return	1	0.022 (0.015)
Office (GB50189-2005 2005GB50189—, 2005GB50189-2005 2005; JGJ/T67-2006 2006JGJ/T67-, 2019JGJ/T67-2006 2006; Mu, Yan, & Qian, 2017)	10	–	–	2.00	30.7 %	18.1 %	30	Ceiling supply, floor return	1	0.010 (0.006)
Classroom (GB99-86, 2012; Y., J. Y.J., 2019)	50	–	–	1.05	42.4 %	29.8 %	14	Ceiling supply, floor return	1	0.030 (0.021)
Restaurant (JG64-89, 1900)	90	–	–	1.05	42.4 %	29.8 %	20	Ceiling supply, ceiling return	0.8	0.027 (0.019)