Table 3.

Regression Results of the Increase in Peak PM_2.5 (µg/m³) in Alternative Models

Train type	1	2	3
Empty Coal	12.8	9.26	8.09
Freight	18.50***	14.06***	14.37***
Full Coal	22.84***	17.37***	19.96 **
R2	0.25	0.25	0.27
n	550	550	360

^*** p < 0.01, ** p < 0.05, * p < 0.1;

Models are: (1) Basic (2) Calibrated monitor (3) Calibrated monitor with wind < mean

Basic model includes wind speed, train speed and a binary variable for each train type