Table 3.

δ calculated based on CFD results of quanta distribution in the breathing zone and the resulting regression equations. (P-value < 0.0000).

Vehicle type		δ for each OR				Regression models ($\delta =a{e}^{b\bullet OD}$)
		15%	25%	35%	45%	a	b	RMSE	R2	Adjust R2
FF	Bus	2.7	2.9	3.4	4.7	1.8028	0.543	0.00324	0.992	0.991
	Shuttle		1.1	1.2	1.5	0.69652	2.0387	0.00203	0.996	0.996
	Aerotrain		1.4	1.7	1.8	1.1198	0.22842	0.000962	0.998	0.998
NF	Bus	17.5	19.5	29.7	35.7	11.527	0.66604	0.0261	0.991	0.990
	Shuttle		3.9	4.8	6.0	1.9973	2.9754	0.000222	1	1
	Aerotrain		2.7	4.4	5.1	1.4627	0.63907	0.00806	0.980	0.977