Association between air pollution in the 2015 winter in South Korea and population size, car emissions, industrial activity, and fossil-fuel power plants: an ecological study

Table 3 Association between the number of days of excessive particulate matter 10 (PM₁₀) and carbon monoxide (CO) in the winter of 2015 and concentration of putative contaminant sources

	CO		PM10
	exp(β)	95% CI	exp(β)	95% CI
Population density (person/km²)^a
Q1(lowest)	1.00		1.00
Q2	3.44	1.96–6.04	3.00	1.46–6.17
Q3	5.07	3.00–8.58	3.89	1.97–7.68
Q4(highest)	3.70	2.19–6.26	1.59*	0.79–3.18
No. of car registrations^b
Q1(lowest)	1.00		1.00
Q2	3.53	1.96–6.38	1.50	0.70–3.21
Q3	3.86	2.22–6.72	1.45*	0.71–2.95
Q4(highest)	5.75	3.32–9.99	2.49	1.23–5.04
No. of car accident^c
Q1(lowest)	1.00		1.00
Q2	2.20	1.23–3.93	1.00	0.47–2.13
Q3	3.14	1.84–5.36	1.67*	0.84–3.32
Q4(highest)	4.33	2.54–7.38	2.23	1.13–4.40
Industrial power usage (Kwh/ km²)^d
Q1(lowest)	1.00		1.00
Q2	2.88	1.64–5.07	2.69	1.31–5.52
Q3	3.93	2.37–6.51	3.19	1.66–6.12
Q4(highest)	3.46	2.09–5.71	1.70*	0.88–3.27
Generation of electricity (Kwh)
No	1.00		1.00
Yes	1.37	1.01–1.86	2.27	1.60–3.21

^apopulation density(persons/km²): Q1 < 98.87, 98.87 ≤ Q2 < 459.19, 459.19 ≤ Q3 < 6329.12, 6329.12 ≤ Q4
^bNo. of car registrations(car/1000): Q1 < 16.43, 16.43 ≤ Q2 < 48.90, 48.90 ≤ Q3 < 98.36, 98.36 ≤ Q4
^cNo. of car accident: Q1 < 213.00, 213.00 ≤ Q2 < 729.00, 729.00 ≤ Q3 < 1521.00, 1521.00 ≤ Q4
^dIndustrial power usage (Kwh/km²): Q1 < 300,926.80, 300,926.80 ≤ Q2 < 1,588,265.70, 1,588,265.70 ≤ Q3 < 8,306,667.40, 8,306,667.40 ≤ Q4

ISSN: 2052-4374