College of Chemistry, Chemical Engineering and Environment, Minnan Normal University, Zhangzhou, 363000, China; Pingtan Environmental Monitoring Center of Fujian, Pingtan, 350400, China.
Pingtan Environmental Monitoring Center of Fujian, Pingtan, 350400, China.
Environ Pollut. 2024 Oct 15;359:124757. doi: 10.1016/j.envpol.2024.124757. Epub 2024 Aug 15.
In the troposphere, ozone (O) formation can be limited by NOx, VOCs, or both, complicating efforts to reduce O by controlling its precursors. This study used formaldehyde (HCHO) data and nitrogen dioxide (NO) data from the Ozone Monitoring Instrument (OMI) to analyze O formation sensitivity in Fujian from 2012 to 2021. Over the past decade, an 8.7% reduction in NO VCDs and a 9.91% increase in HCHO VCDs were observed. Due to differences in the primary driving factors, HCHO VCDs exhibit a characteristic seasonal pattern with higher in summer and lower in winter, whereas NO VCDs show the opposite trend. O formation chemistry was accurately diagnosed by combining satellite-based data and ground-based O data. A new threshold value (3.3-4.6) was derived to determine the transition from VOC-limited to NOx-limited O formation regimes. Results showed that O sensitivity exhibited pronounced seasonal variations. The VOC-limited regime predominates throughout the entire Fujian region in winter, whereas it occupies only 5% of the area in summer. A VOC-limited region was found widely across Fujian on an annual average, but it decreased by 24% over 10 years. Transitional areas experienced a 19% increase. In two natural emission reduction cases (reductions during the Chinese Lunar New Year holiday and reductions in weekend traffic emissions compared to weekdays), ground-level O effectively captured the impacts of sensitivity changes. The impact suggests that when Fujian is in the VOC control region, a significant reduction in NOx, without effective VOC control, might lead to an O increase. The importance of controlling VOC emissions is highlighted in Fujian. This study enhances the understanding of O formation regimes in southeastern China, which is crucial for developing O prevention and control strategies.
在对流层中，臭氧（O）的形成可能受到氮氧化物（NOx）、挥发性有机化合物（VOCs）或两者的限制，这使得通过控制其前体来减少 O 的努力变得复杂。本研究使用臭氧监测仪（OMI）的甲醛（HCHO）数据和二氧化氮（NO）数据，分析了 2012 年至 2021 年福建 O 形成的敏感性。在过去的十年中，NOx 的体积混合比（VCD）降低了 8.7%，HCHO 的 VCD 增加了 9.91%。由于主要驱动因素的差异，HCHO VCD 表现出夏季高、冬季低的特征季节性模式，而 NO VCD 则呈现相反的趋势。通过结合卫星数据和地面 O 数据，准确诊断了 O 形成的化学过程。确定了一个新的阈值（3.3-4.6）来确定从 VOC 限制到 NOx 限制 O 形成区域的转变。结果表明，O 的敏感性表现出明显的季节性变化。在整个福建地区，冬季以 VOC 限制为主，而夏季仅占 5%。福建地区全年平均存在广泛的 VOC 限制区，但在过去 10 年中减少了 24%。过渡区增加了 19%。在两个自然减排案例（中国农历新年假期期间的减排和周末交通排放与工作日相比的减排）中，地面 O 有效地捕捉到了敏感性变化的影响。这一影响表明，当福建处于 VOC 控制区时，在没有有效 VOC 控制的情况下，大量减少 NOx 可能导致 O 增加。本研究强调了控制 VOC 排放的重要性，这对制定中国东南部的 O 预防和控制策略具有重要意义。
