Investigation on the Impacts of COVID-19 Lockdown and Influencing Factors on Air Quality in Greater Bangkok, Thailand

Table 2

Total variance explaining the principal components of air pollutants and meteorological elements in 2019 and 2020 over Greater Bangkok.

2019	Before			Lockdown			After
Component	Eigen value	Variance (%)	Cumulative (%)	Eigen value	Variance (%)	Cumulative (%)	Eigen value	Variance (%)	Cumulative (%)
1	3.84	27.40	27.40	3.50	25.00	25.00	3.58	25.60	25.60
2	2.55	18.20	45.60	2.32	16.60	41.60	2.21	15.80	41.40
3	1.22	8.70	54.40	1.34	9.50	51.10	1.44	10.30	51.60
4	1.08	7.70	62.10	1.28	9.10	60.30	1.34	9.50	61.20
5	1.02	7.30	69.30	1.14	8.10	68.40	1.16	8.30	69.40
6	0.83	5.90	75.30	0.98	7.00	75.40	0.87	6.20	75.70
7	0.82	5.80	81.10	0.77	5.50	80.80	0.84	6.00	81.70
8	0.66	4.70	85.80	0.64	4.60	85.40	0.57	4.10	85.70
9	0.61	4.40	90.10	0.58	4.20	89.60	0.53	3.80	89.50
10	0.45	3.20	93.40	0.46	3.30	92.80	0.45	3.20	92.70
2020	Before			Lockdown			After
Component	Eigen value	Variance (%)	Cumulative (%)	Eigen value	Variance (%)	Cumulative (%)	Eigen value	Variance (%)	Cumulative (%)
1	5.15	36.70	36.70	3.58	25.50	25.50	3.25	23.00	23.00
2	1.67	11.90	48.60	2.20	15.70	41.20	2.43	17.20	40.20
3	1.22	8.70	57.30	1.84	13.10	54.20	1.68	11.90	52.10
4	1.09	7.80	65.10	1.61	11.50	65.70	1.62	11.50	63.60
5	0.96	6.80	71.90	0.99	7.00	72.80	1.15	8.10	71.70
6	0.89	6.40	78.30	0.85	6.10	78.80	0.87	6.10	77.90
7	0.86	6.10	84.40	0.74	5.30	84.10	0.80	5.70	83.60
8	0.60	4.30	88.70	0.57	4.10	88.20	0.61	4.30	87.90
9	0.48	3.50	92.20	0.47	3.30	91.50	0.52	3.70	91.60
10	0.43	3.10	95.30	0.41	2.90	94.40	0.42	3.00	94.50