Table 2.

95% confidence interval of the difference in pollutants' concentration for each pair of order category.

Pair of order categories	PM2.5 (μg/m3)	PM10 (μg/m3)	SO2 (ppb)	NO2 (ppb)	CO (ppm)
SO40 – SO40M	−0.69, −0.54*	1.96, 2.67*	0.16, 0.47*	0.16, 0.47*	−0.01, −0.001*
SO40 – AO	−0.92, −0.72*	−11.12, −7.998*	1.54, 1.75*	1.54, 1.75*	0.04, 0.06*
SO40 – NSO	1.27, 1.5*	5.09, 6.12*	3.93, 4.12*	3.93, 4.12*	0.02, 0.04*
SO40M – AO	−0.32, −0.096*	−13.42, −10.32*	1.17, 1.49*	1.17, 1.49*	0.05, 0.07*
SO40M – NSO	1.87, 2.12*	2.81, 3.78*	3.57, 3.86*	3.57, 3.86*	0.02, 0.04*
AO – NSO	2.06, 2.34*	13.57, 16.76*	2.28, 2.48*	2.28, 2.48*	−0.04, −0.014*