Skip to main content

View full-text article in PMC

. 2020 Oct 22;23(6):9581–9608. doi: 10.1007/s10668-020-01034-z

Table 6.

Pollutant matter and gases before and after lockdown in Chennai, 2020

Types of pollutants	Before lockdown
	17-Feb-2020		24-Feb-2020		02-Mar-2020		09-Mar-2020		16-Mar-2020
	High	Low	High	Low	High	Low	High	Low	High	Low
PM_2.5	72.9998	40.0023	68.9998	37.0023	110.993	18.0015	91.997	18.015	75.9998	35.0001
PM₁₀	52.9983	22.0005	58.995	21.0007	54.321	20.993	27.9988	9.0041	50.0001	20.6312
NO₂	22.9995	5.0012	18.9996	5.0005	23.01	3.01	19.9994	3.0051	21.9901	1.0013
NH₃	11.9999	7.002	38.996	11.0002	12.99	5.893	90.9991	9.0031	11.9998	0.9998
SO₂	55.9982	7.0006	47.9985	6.0005	48.7	4.003	7.991	4.003	38.0001	5.0124
CO	68.9991	31.0001	96.998	21.002	88.327	15.0019	69.9983	15.0015	77.0001	16.0001
O₃	21.9997	13.001	24.9998	19.0001	13.63	5.983	39.321	4.002	41.0001	0.9998
AQI	198.47	40.28	187.59	41.01	195.48	39.19	189.59	38.79	187.89	40.13

Types of pollutants	After lockdown																			Overall variation
	24-Mar-2020		30-Mar-2020		08-Apr-2020		14-Apr-2020		21-Apr-2020		29-Apr-2020		6-May-2020			13-May-2020		20-May-2020		Overall variation
	High	Low	High	Low	High	Low	High	Low	High	Low	High	Low	High		Low	High	Low	High	Low	Net	%
PM_2.5	58.3249	30.0001	63.001	27.9998	42.9998	10.0001	54.9998	0.998	35.0001	4.0001	16.0018	7.0001		14.9998	9.0001	13.69	7.01	13.59	8.59	− 33.723	− 59.266
PM₁₀	30.9998	14.0001	38.001	11.214	31.0001	18.0098	18.9998	11.001	20.9998	16.0001	22.0001	11.0019		16.9998	7.001	20.59	10.59	16.49	7.01	− 15.9105	− 47.0804
NO₂	20.0001	1.0001	21.001	2.998	16.0001	1.998	26.9998	1.998	8.0001	0.998	12.9998	3.0098		9.9998	1.0001	9.49	1.01	8.89	1.19	− 4.14708	− 33.4397
NH₃	14.0001	7.9998	10.001	5.0012	11.9998	5.0019	12.001	6.001	9.0001	5.0001	10.9998	2.0018		10.0018	1.0009	10.01	1.01	9.89	1.0009	− 12.7593	− 63.5163
SO₂	9.0009	5.0001	11.0001	3.9287	8.019	3.9998	20.0001	3.998	8.0001	3.998	8.9998	2.00019		8.9998	2.0001	8.49	1.59	8.01	1.01	− 15.9127	− 70.8152
CO	48.9998	1.0001	38.9998	0.0998	37.0001	19.0002	41.0001	17.001	37.0019	17.0001	45.0011	19.9998		36.0001	14.0018	32.49	14.01	31.89	14.01	− 24.1269	− 48.3188
O₃	40.9998	5.9998	65.889	6.0001	66.89	9.0019	78.49	11.001	120.998	10.0098	101.998	19.9998		124.0018	13.9909	124.01	12.59	123.01	13.01	34.2669	186.2974
AQI	185.79	20.57	145.79	20.49	152.69	20.59	150.589	19.89	123.69	20.78	101.29	17.89		89.789	17.79	88.79	17.01	79.89	16.89	− 44.1638	− 38.1241

HHS Vulnerability Disclosure