From: Do green spaces affect the spatiotemporal changes of PM2.5 in Nanjing?
Daily PM2.5 (μg m−3) | Pollution class | No. of days and proportion (%) during the study period | ||||
---|---|---|---|---|---|---|
Total | Spring | Summer | Autumn | Winter | ||
0–35 | Excellent | 92 (17.2) | 20 (21.7) | 32 (34.8) | 27 (29.4) | 13 (14.1) |
35–75 | Good | 247 (46.3) | 84 (34.0) | 51 (20.6) | 60 (24.3) | 52 (21.1) |
Sub total | 339 (63.5) | 104 (30.7) | 83 (24.5) | 87 (25.6) | 65 (19.2) | |
75–115 | Light | 115 (21.5) | 23 (20.0) | 10 (8.7) | 38 (33.0) | 44 (38.3) |
115–150 | Intermediate | 43 (8.1) | 5 (11.6) | 2 (4.7) | 17 (39.5) | 19 (44.2) |
150–250 | Heavy | 28 (5.2) | 2 (7.1) | 2 (7.1) | 4 (14.3) | 20 (71.5) |
>250 | Very heavy | 9 (1.7) | 0 (0.0) | 0 (0.0) | 0 (0.0) | 9 (100.0) |
Sub total | 195 (36.5) | 30 (15.4) | 14 (7.2) | 59 (30.2) | 92 (47.2) |