Table 2 Panel regression results of the main models in different temporal scales

From: Non-linear relationships between air temperature and river water quality revealed by a panel dataset of 276 Chinese cities

 

(1) DO

(2) DO

(3) DO

(4) DO

(5) CODMn

(6) CODMn

Temp

−0.00551***

−0.00775***

−0.00931***

−0.0103***

−0.0047*

−0.00777***

(0.0019)

(0.002)

(0.0019)

(0.0019)

(0.0028)

(0.003)

Temp2

−0.000385***

−0.000483***

−0.000546***

−0.00063***

−0.000295***

−0.000356***

(0.000059)

(0.000062)

(0.000064)

(0.00007)

(0.000056)

(0.000062)

Prec

−2.14***

−1.45***

−1.29***

−0.779***

−0.253

0.541

(0.63)

(0.45)

(0.38)

(0.28)

(0.99)

(0.71)

GDP

−0.000134*

−0.000134*

−0.000131*

−0.000131*

0.0000866

0.000134

(0.000071)

(0.000073)

(0.000074)

(0.000077)

(0.00037)

(0.00038)

Industry

0.376*

0.314

0.291

0.223

0.646

0.584

(0.22)

(0.22)

(0.22)

(0.22)

(0.85)

(0.84)

Emission

0.0277

0.0299

0.0302

0.0331

−0.0412

−0.0319

(0.019)

(0.02)

(0.02)

(0.022)

(0.065)

(0.068)

Temp × Prec

0.0559**

0.0362*

0.0349**

0.0243**

0.0179

−0.0187

(0.028)

(0.02)

(0.016)

(0.012)

(0.044)

(0.032)

N

36243

18790

12866

6803

25557

13448

adj. R2

0.465

0.475

0.474

0.482

0.601

0.605

BIC

6474

2232

1421

402

30512

15,826

Time Fixed Effect

5 day

10 day

15 day

Month

5 day

10 day

 

(7) CODMn

(8) CODMn

(9) NH3-N

(10) NH3-N

(11) NH3-N

(12) NH3-N

Temp

−0.00942***

−0.0111***

−0.0165***

−0.0169***

−0.0168***

−0.0138**

(0.0032)

(0.0038)

(0.0046)

(0.0054)

(0.0059)

(0.0066)

Temp2

−0.000421***

−0.00045***

−0.000433***

−0.000503***

−0.000556***

−0.00051***

(0.000076)

(0.00011)

(0.00013)

(0.00016)

(0.00018)

(0.00019)

Prec

0.254

0.506

−1.34

−1.05

−0.137

0.482

(0.78)

(0.47)

(1.6)

(1.3)

(1.1)

(0.84)

GDP

0.000136

0.000252

0.000483

0.000542

0.000586

0.000687

(0.00038)

(0.0004)

(0.00067)

(0.00076)

(0.00078)

(0.00084)

Industry

0.616

0.428

−0.262

−0.398

−0.471

−0.6

(0.85)

(0.84)

(0.81)

(0.89)

(0.92)

(1)

Emission

−0.0366

−0.043

−0.0832

−0.0838

−0.0842

−0.096

(0.064)

(0.066)

(0.14)

(0.15)

(0.15)

(.16)

Temp×Prec

−0.00522

−0.0161

0.105

0.0789

0.0412

0.00506

(0.033)

(0.02)

(0.066)

(0.054)

(0.048)

(0.035)

N

9312

5037

29846

15860

11108

6123

adj. R2

0.602

0.607

0.461

0.461

0.471

0.495

BIC

11,005

5680

69,074

36,896

26,199

14,688

Time Fixed Effect

15 day

Month

5 day

10 day

15 day

Month

  1. Note: The coefficients are the regression results of the main models for DO, CODMn, and NH3-N, representing the 100%-point effect on water quality per unit increase for a given temperature. “Temp”, the air temperature; “Prec”, total precipitation; “GDP”, total GDP; “Industry”, the percentage of GDP output of the secondary sector; “Emission”, wastewater discharged; “N”, the number of observations. Standard errors are clustered at the municipal level and are shown in parenthesis.
  2. (*p < 0.1, **p < 0.05, ***p < 0.01).
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