Background
Methods
Study area and data collection
Statistical and temporal analysis
Trajectory models
Results and discussion
Descriptive statistics
Variable PM10 | N | Minimum (μg/m3) | Maximum (μg/m3) | Mean (μg/m3) | Std. deviation |
---|---|---|---|---|---|
Station 65 | |||||
Annual | 2922 | 1.6 | 371.1 | 41.9 | 35.5 |
Summer | 714 | 8.5 | 371.1 | 78.6 | 53.2 |
Rainy | 1224 | 1.6 | 80.6 | 23.2 | 10.2 |
Winter | 984 | 6.8 | 130.3 | 40.4 | 17.3 |
Station 73 | |||||
Annual | 2741 | 3.00 | 129.6 | 37.4 | 22.8 |
Summer | 625 | 12.2 | 129.6 | 56.1 | 25.8 |
Rainy | 1178 | 3.0 | 80.2 | 27.1 | 14.5 |
Winter | 938 | 3.0 | 80.2 | 27.6 | 15.5 |
Seasonal meteorological variables
Station | Meteorological Factor | Contrast | P-value |
---|---|---|---|
Station 65 | Temp | Rainy vs Winter | < 0.0001 |
Rainy vs Summer | 0.0230 | ||
Summer vs Winter | < 0.0001 | ||
Relative Humidity | Rainy vs Winter | < 0.0001 | |
Rainy vs Summer | < 0.0001 | ||
Summer vs Winter | < 0.0001 | ||
Pressure | Rainy vs Winter | 0.0244 | |
Rainy vs Summer | < 0.0001 | ||
Summer vs Winter | < 0.0001 | ||
Station 73 | Temp | Rainy vs Winter | < 0.0001 |
Rainy vs Summer | < 0.0001 | ||
Summer vs Winter | < 0.0001 | ||
Relative Humidity | Rainy vs Winter | < 0.0001 | |
Rainy vs Summer | < 0.0001 | ||
Summer vs Winter | < 0.0001 | ||
Pressure | Rainy vs Winter | 0.2585 | |
Rainy vs Summer | < 0.0001 | ||
Summer vs Winter | < 0.0001 |
Pollution | Station | Contrast | P-value |
---|---|---|---|
PM10 | Station 65 | Rainy vs Winter | < 0.0001 |
Rainy vs Summer | < 0.0001 | ||
Summer vs Winter | < 0.0001 | ||
Station 73 | Rainy vs Winter | < 0.0001 | |
Rainy vs Summer | < 0.0001 | ||
Summer vs Winter | < 0.0001 |
Comparison of MLR models
Chiang Rai (Station 65) | Chiang Rai (Station 73) |
---|---|
Ya = 46.9 + 56.6x1 + 1.3x2 + 0.3x3 + 0.7x4 | Ya = 22.1 + 45.2x1 + 1.1x2 + 0.4x4 |
Ys = 1486.0 + 116.8x1 + 0.7x2 + 0.6x3 − 0.9x4 − 1.5x5 | Ys = − 87.3 + 54.4x1 + 1.5x2 + 2.6x3 |
Yr = 67.0 + 9.3x1 + 0.4x2 + 0.03x3 − 0.3x4 − 0.03x5 | Yr = − 124.0 − 6.11x1 + 4.4x3 + 0.5x4 |
Yw = 11.4 + 10.7x1 + 1.5x2 + 0.7x3 − 0.2x4 + 0.03x5 | Yw = − 33.9 + 58.4x1 + 1.9x2 |
Seasonal Regression | Fitting results | |||
---|---|---|---|---|
R2 | RMSE | VIF | DW | |
Station 65 | ||||
Annual | 0.61 | 22.15 | 1.07–1.59 | 0.63 |
Summer | 0.73 | 27.95 | 1.19–1.39 | 0.41 |
Rainy | 0.24 | 8.88 | 1.14–1.57 | 0.58 |
Winter | 0.40 | 13.40 | 1.01–1.27 | 0.64 |
Station 73 | ||||
Annual | 0.52 | 15.83 | 1.01–1.68 | 0.67 |
Summer | 0.61 | 16.45 | 1.03–1.17 | 0.98 |
Rainy | 0.12 | 13.72 | 1.10–2.47 | 0.64 |
Winter | 0.67 | 11.06 | 1.00 | 1.18 |
Parameter | Station 65 | Station 73 | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
Summer | PM10 | CO | O3 | Temp | RH | P | PM10 | CO | O3 | Temp | RH | P |
PM10 | 1.00 | 0.71 | 0.47 | 0.31 | −0.60 | −0.17 | 1.00 | 0.46 | 0.56 | 0.26 | − 0.58 | − 0.42 |
CO | 0.71 | 1.00 | 0.20 | 0.05 | −0.34 | 0.07 | 0.46 | 1.00 | 0.24 | 0.21 | −0.53 | − 0.02 |
O3 | 0.47 | 0.20 | 1.00 | 0.39 | −0.38 | −0.23 | 0.56 | 0.24 | 1.00 | 0.38 | −0.35 | −0.43 |
Temp | 0.31 | 0.05 | 0.39 | 1.00 | −0.35 | −0.27 | 0.26 | 0.21 | 0.38 | 1.00 | −0.40 | −0.63 |
RH | −0.60 | −0.34 | − 0.38 | −0.35 | 1.00 | 0.19 | −0.58 | −0.53 | − 0.35 | −0.40 | 1.00 | 0.25 |
P | −0.17 | 0.07 | −0.23 | −0.27 | 0.19 | 1.00 | −0.42 | −0.02 | − 0.43 | −0.63 | 0.25 | 1.00 |
Rainy | PM10 | CO | O3 | Temp | RH | P | PM10 | CO | O3 | Temp | RH | P |
PM10 | 1.00 | 0.29 | 0.30 | 0.36 | −0.42 | 0.15 | 1.00 | −0.10 | −0.10 | 0.25 | −0.23 | − 0.31 |
CO | 0.29 | 1.00 | −0.06 | 0.08 | 0.06 | 0.06 | −0.10 | 1.00 | −0.41 | 0.33 | −0.02 | −0.72 |
O3 | 0.30 | −0.06 | 1.00 | 0.40 | −0.38 | 0.07 | −0.10 | −0.41 | 1.00 | −0.27 | − 0.32 | 0.59 |
Temp | 0.36 | 0.08 | 0.40 | 1.00 | −0.61 | 0.08 | 0.25 | 0.33 | −0.27 | 1.00 | −0.80 | −0.64 |
RH | −0.42 | 0.06 | −0.38 | −0.61 | 1.00 | −0.16 | − 0.23 | −0.02 | − 0.32 | −0.80 | 1.00 | −0.14 |
P | 0.15 | 0.06 | 0.07 | 0.08 | −0.16 | 1.00 | −0.31 | −0.72 | 0.59 | −0.64 | − 0.14 | 1.00 |
Winter | PM10 | CO | O3 | Temp | RH | P | PM10 | CO | O3 | Temp | RH | P |
PM10 | 1.00 | 0.28 | 0.60 | −0.26 | −0.41 | 0.27 | 1.00 | 0.00 | 0.59 | −0.34 | −0.24 | 0.29 |
CO | 0.28 | 1.00 | 0.09 | −0.01 | −0.07 | 0.09 | 0.00 | 1.00 | −0.06 | 0.09 | −0.27 | 0.26 |
O3 | 0.60 | 0.09 | 1.00 | −0.20 | − 0.46 | 0.10 | 0.59 | −0.06 | 1.00 | −0.23 | − 0.71 | 0.21 |
Temp | −0.26 | −0.01 | − 0.20 | 1.00 | 0.08 | −0.20 | − 0.34 | 0.09 | − 0.23 | 1.00 | 0.07 | −0.79 |
RH | −0.41 | −0.07 | − 0.46 | 0.08 | 1.00 | −0.16 | − 0.24 | −0.27 | − 0.71 | 0.07 | 1.00 | −0.07 |
P | 0.27 | 0.09 | 0.10 | −0.20 | −0.16 | 1.00 | 0.29 | 0.26 | 0.21 | −0.79 | −0.07 | 1.00 |