Table 2. Comparison of environmental indicators in South Korea and North Korea

	South Korea			North Korea			P–value
	n	Mean	SD	n	Mean	SD
Environmental indicator
PM2·5 (µg/m3)	10	28.3	2	10	36.5	2.8	0.002
CO2 emissions (metric tons per capita)	17	10.6	1	17	2.3	0.9	<0.001
N2O emissions (thousand metric tons of CO2 equivalent)	13	14,338.0	1,996.8	13	3,286.2	74.8	<0.001
Methane emissions (kt of CO2 equivalent)	13	31,680.5	703.4	13	18,390.4	671.1	<0.001
Fossil fuel (% of total)	16	82.4	1.2	15	79.5	13.1	0.421

P-value by Wilcoxon’s sign rank test.