School of Environmental Science, Liaoning University, Shenyang, 110036, China.
Key Lab of Environmental Optics & Technology, Anhui Institute of Optics and Fine Mechanics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, 230031, China.
Environ Pollut. 2022 Aug 1;306:119424. doi: 10.1016/j.envpol.2022.119424. Epub 2022 May 7.
Ground-based Multi-Axis Differential Optical Absorption Spectroscopy (Max-DOAS) measurements of nitrogen dioxide (NO) were continuously obtained from January to November 2019 in northeastern China (NEC). Seasonal variations in the mean NO vertical column densities (VCDs) were apparent, with a maximum of 2.9 × 10 molecules cm in the winter due to enhanced NO emissions from coal-fired winter heating, a longer photochemical lifetime and atmospheric transport. Daily maximum and minimum NO VCDs were observed, independent of the season, at around 11:00 and 13:00 local time, respectively, and the most obvious increases and decreases occurred in the winter and autumn, respectively. The mean diurnal NO VCDs at 11:00 increased to at 08:00 by 1.6, 5.8, and 6.7 × 10 molecules cm in the summer, autumn and winter, respectively, due to increased NO emissions, and then decreased by 2.8, 4.2, and 5.1 × 10 molecules cm at 13:00 in the spring, summer, and autumn, respectively. This was due to strong solar radiation and increased planetary boundary layer height. There was no obvious weekend effect, and the NO VCDs only decreased by about 10% on the weekends. We evaluated the contributions of emissions and transport in the different seasons to the NO VCDs using a generalized additive model, where the contributions of local emissions to the total in the spring, summer, autumn, and winter were 89 ± 12%, 92 ± 11%, 86 ± 12%, and 72 ± 16%, respectively. The contribution of regional transport reached 26% in the winter, and this high contribution value was mainly correlated with the northeast wind, which was due to the transport channel of air pollutants along the Changbai Mountains in NEC. The NO/SO ratio was used to identify NO from industrial sources and vehicle exhaust. The contribution of industrial NO VCD sources was >66.3 ± 16% in Shenyang due to the large amount of coal combustion from heavy industrial activity, which emitted large amounts of NO. Our results suggest that air quality management in Shenyang should consider reductions in local NO emissions from industrial sources along with regional cooperative control.
在中国东北地区（NEC），从 2019 年 1 月到 11 月，我们持续进行了基于地面的多轴差分光学吸收光谱（Max-DOAS）测量，以获取二氧化氮（NO）的数据。NO 垂直柱浓度（VCD）的季节性变化明显，冬季由于燃煤冬季供暖导致的 NO 排放量增加、较长的光化学反应寿命和大气输送，NO VCD 达到了 2.9×10 分子 cm 的最大值。无论季节如何，每天的最大和最小 NO VCD 分别在当地时间 11 点和 13 点左右观测到，其中冬季和秋季的增幅和降幅最为明显。由于 NO 排放量增加，夏季、秋季和冬季 11 点的平均日 NO VCD 分别在 08 点增加了 1.6、5.8 和 6.7×10 分子 cm，而在春季、夏季和秋季 13 点则分别减少了 2.8、4.2 和 5.1×10 分子 cm，这是由于太阳辐射增强和边界层高度增加所致。没有明显的周末效应，周末时 NO VCD 仅下降约 10%。我们使用广义加性模型评估了不同季节排放和输送对 NO VCD 的贡献，其中本地排放对春季、夏季、秋季和冬季总排放量的贡献分别为 89±12%、92±11%、86±12%和 72±16%。冬季区域输送的贡献达到 26%，这一高贡献值主要与东北风有关，这是由于污染物沿 NEC 长白山的输送通道。NO/SO 比用于识别来自工业源和车辆尾气的 NO。由于重工业活动中大量燃煤，沈阳工业源 NO VCD 贡献>66.3±16%。我们的结果表明，沈阳的空气质量管理应考虑减少工业源的本地 NO 排放，同时进行区域合作控制。
