. 2021 May 14;14(10):1619–1632. doi: 10.1007/s11869-021-01043-5

Table 2.

Effects of central heating and heating period on AQI value and 6 criteria pollutants concentration

	AQI		PM_2.5 (μg/m³)		PM₁₀ (μg/m³)		SO₂ (μg/m³)		NO₂ (μg/m³)		CO (mg/m³)		O₃ (μg/m³)
	HP	N-HP	HP	N-HP	HP	N-HP	HP	N-HP	HP	N-HP	HP	N-HP	HP	N-HP
CH	124.79 ± 1.21^§	80.97 ± 0.56^#	90.61 ± 1.10^§	44.22 ± 0.47^#	136.40 ± 1.55^§	89.61 ± 0.78^#	42.90 ± 0.65^§	13.18 ± 0.15^#	53.24 ± 0.35^§	36.88 ± 0.18^#	1.53 ± 0.81^§	0.81 ± 0.00^#	32.98 ± 0.29^*	69.60 ± 0.41
N-CH	84.67 ± 0.61^*	60.32 ± 0.31	59.13 ± 0.51^*	33.81 ± 0.23	87.45 ± 0.69^*	59.42 ± 0.39	14.17 ± 0.14^*	10.03 ± 0.06	46.32 ± 0.29^*	35.21 ± 0.17	1.02 ± 0.00^*	0.79 ± 0.00	40.55 ± 0.30^*	64.85 ± 0.32

Values presented as mean ± standard error

CH central heating area, N-CH none-central heating area, HP heating period, N-hp none-heating period

^§Significant vs. N-CH and N-HP

^#Significant vs. N-CH

^*Significant vs. N-HP