Table 1.

Summary statistics of suicide (daily mean and standard deviation), air pollutants and weather factors (median and interquartile range) for each city.

Country	City	Total number of suicide	Daily mean suicide counts	${\text{NO}}_2$ (ppb)	${\text{SO}}_2$ (ppb)	${\mathrm{PM}}_{10}$ (${\mathrm{\mu }\mathrm{g}/\mathrm{m}}^3$)	${\mathrm{PM}}_{2.5}$ (${\mathrm{\mu }\mathrm{g}/\mathrm{m}}^3$)	${\mathrm{PM}}_{10-2.5}$ (${\mathrm{\mu }\mathrm{g}/\mathrm{m}}^3$)	Temperature ($\mathrm{°}\mathrm{C}$)	Sunshine duration (hour)
South Korea	Seoul	19,218	$5.3\pm 2.9$	$35.0\pm 18.1$	$4.7\pm 2.7$	$53.0\pm 38.3$	$26.0\pm 20.0$	$25.0\pm 18.9$	$14.4\pm 17.8$	$5.4\pm 7.1$
	Busan	8,971	$2.5\pm 1.7$	$22.8\pm 12.5$	$5.6\pm 3.2$	$49.9\pm 28.8$	—	—	$15.7\pm 12.9$	$7.0\pm 6.9$
	Incheon	6,204	$1.7\pm 1.4$	$27.1\pm 15.1$	$6.6\pm 3.2$	$53.2\pm 34.2$	—	—	$13.9\pm 16.9$	$6.8\pm 7.0$
	Daegu	5,420	$1.5\pm 1.3$	$22.8\pm 13.4$	$5.2\pm 3.2$	$50.4\pm 30.8$	—	—	$15.7\pm 16.3$	$6.9\pm 6.7$
Japan	Tokyoa	46,519	$4.2\pm 2.3$	$30.3\pm 14.8$	$6.7\pm 7.1$	$40.2\pm 32.4$	$17.8\pm 11.9$	$11.1\pm 10.5$	$16.5\pm 13.4$	$5.6\pm 8.0$
	Nagoya	11,685	$1.1\pm 1.1$	$26.2\pm 13.1$	$6.2\pm 4.9$	$40.1\pm 30.9$	—	—	$16.3\pm 15.0$	$6.4\pm 7.4$
	Osaka	18,911	$1.7\pm 1.4$	$31.7\pm 15.9$	$7.3\pm 6.1$	$38.6\pm 30.6$	—	—	$17.2\pm 14.8$	$5.9\pm 6.9$
Taiwan	Taipei	9,481	$1.9\pm 1.6$	$26.9\pm 10.0$	$4.6\pm 3.7$	$47.6\pm 29.7$	$25.8\pm 18.8$	$20.5\pm 9.9$	$23.8\pm 8.6$	$3.4\pm 7.1$
	Taichung	3,352	$0.7\pm 0.8$	$22.3\pm 11.2$	$3.7\pm 2.6$	$56.2\pm 41.7$	—	—	$24.8\pm 7.6$	$6.5\pm 6.2$
	Kaohsiung	5,050	$1.0\pm 1.1$	$24.5\pm 17.1$	$9.3\pm 5.9$	$80.6\pm 66.8$	—	—	$26.3\pm 5.8$	$6.8\pm 5.5$

Note: —, data unavailable; ${\text{NO}}_2$, nitrogen dioxide; ${\mathrm{PM}}_{2.5}$, particulate matter with aerodynamic diameter $\le 2.5\mathrm{\mu }\mathrm{m}$; ${\mathrm{PM}}_{10}$, particulate matter with aerodynamic diameter $\le 10\mathrm{\mu }\mathrm{m}$; ${\mathrm{PM}}_{10-2.5}$, coarse particulate matter; ${\text{SO}}_2$, sulfur dioxide. Study period varies by city: 10 years in Korean cities, 30 years in Japanese cities, and 14 years in Taiwanese cities. The data on ${\mathrm{PM}}_{2.5}$ and ${\mathrm{PM}}_{10-2.5}$ were limited to 8 years in Seoul; 6 years, 2 months in Tokyo; and 2 years in Taipei. The summary statistics of the particulate matter were calculated after excluding extremely high concentrations.

^a23 special wards covering the most populous area of Tokyo.