This paper studied the characteristics and formation mechanisms of local photochemical pollution in Beijing during summer. Firstly, based on the meteorological observations, we obtained four typical meteorological clusters(M1~M4)based on the meteorological observations by using the K-means clustering algorithm and found the significant O3 pollution difference among M1~M4. Then, under 2021 emissions of this city, we further simulated the local photochemical evolution of Beijing urban plumes respectively for four meteorological clusters, via a 0-D box model with the MCM(v3.3.1). The simulation results showed the daytime-averaged net O3 production rate was 7.91×10-9(M1), 7.58×10-9(M2), 7.18×10-9(M3), 3.55×10-9(M4)·h-1, but O3 formation & loss pathways were very similar. O3 formation was in the VOCs-limited regime, but its sensitivity to VOCs apparently decreased from M1 to M4. However, the simulated HCHO and CH3CHO had a little differences between various meteorological conditions, as well as their production rates and formation & loss pathways. The linear response of HCHO to VOCs indicated it could be as the good tracer for VOCs level. Finally, we calculated the O3 increment reactivity(IR)of 65 VOCs species for each meteorological cluster, and found the differences in IR between low-reactivity and high-reactivity VOCs became significantly smaller under the M1 compared to M4, implying the importance of strengthening the control of low-reactivity components VOCs in on O3 pollution days.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |