Abstract:
The significance of oxygenated volatile organic compounds (OVOCs) in the atmospheric environment has become increasingly evident. Studying OVOCs in Beijing is crucial for formulating effective ozone pollution prevention and control strategies. Consequently, from September 2023 to August 2024, continuous monitoring was conducted at the Beijing Ecological Environment Monitoring Center for a total of 102 VOCs, including OVOCs. The concentration change characteristics, activity and sources of OVOCs were analyzed, and the sensitivity of O
3 formation and the reduction effects of precursors during the period from May to August 2024 were evaluated. The findings are summarized as follows: (1) During the observation period, the total mixing ratio of volatile organic compounds (TVOC) was 35.2×10
−9±17.2×10
−9, while the mixing ratio of OVOCs was 12.2×10
−9±6.4×10
−9, accounting for 34.5%, second only to alkanes. The OVOCs species with relatively high mixing ratio mainly included formaldehyde, acetone, and acetaldehyde. (2) The seasonal variation of OVOCs concentrations exhibited a trend of higher levels in summer and lower levels in winter, while the diurnal variation presented a double-peak trend of being slightly higher at noon and in the evening. The variation pattern was significantly different from that of other categories of VOCs. (3) The contribution rate of OVOCs to the ozone formation potential was 56.1%. Among them, the contribution rates of formaldehyde and acetaldehyde to the ozone formation potential accounted for 40.6% of the TVOC, indicating their high reactivity. (4) The source apportionment revealed that OVOCs such as formaldehyde, acetaldehyde, acetone and propionaldehyde shared similar sources. Among them, the contribution rates of background sources and secondary sources were relatively high overall, ranging from 35.9% to 49.8% and 27.3% to 40.6%, respectively. The contribution rates of natural sources and primary anthropogenic sources were generally low, ranging from 8.0% to 13.7% and 4.3% to 15.6%, respectively. (5) The mixing ratio of OVOCs in Beijing was strongly affected by southern air mass, and the transportation distance of the air mass was relatively far. (6) O
3 sensitivity analysis and analysis of emission reduction scenarios from May to August 2024 indicated that reducing anthropogenic VOCs can effectively lower O
3 generation. Moreover, when NO
x is emissions were reduced by more than 30%, O
3 formation further decreased. The research shows that the mixing ratio of OVOCs in Beijing is high and their activity is strong, with significant contributions from secondary sources and background sources. The application of OVOCs monitoring data can effectively improve the accuracy of determining the O
3 generation sensitivity. On the basis of controlling local emissions, strengthening joint VOC control measures across North China, with coordinated control of VOCs and NO
x, is essential for effectively mitigating O
3 pollution.