Underestimated ammonia vehicular emissions in metropolitan city revealed by on-road mobile measurement
Underestimated ammonia vehicular emissions in metropolitan city revealed by on-road mobile measurement
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DOI：
10.1088/1748-9326/acf94a
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发表时间：
2023-09
影响因子：
6.7
通讯作者：
Chuanqi Gu;Shanshan Wang;Jian Zhu;Wenhao Dai;Jiaqing Liu;Ruibin Xue;Xiang Che;Yanfen Lin;Yusen Duan;M. Wenig;Bin Zhou
中科院分区：
文献类型：
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作者：
Chuanqi Gu;Shanshan Wang;Jian Zhu;Wenhao Dai;Jiaqing Liu;Ruibin Xue;Xiang Che;Yanfen Lin;Yusen Duan;M. Wenig;Bin Zhou
大气氨（NH3）在氮循环中起着重要作用，对空气质量、生态平衡和气候变化具有重要影响。虽然与自然和农业过程有关的NH3一直被认为是主要来源，但与燃烧有关的NH3的贡献，特别是来自车辆排放的NH3，仍在不断增加。我们发现，基于移动测量的高道路NH3浓度出现在大城市，并推断过去城市车辆NH3排放量可能被低估。环城公路和隧道的NH3排放系数（EFs）分别比欧七最新标准高出74%和20%。为了量化低估的程度，采用基于汽车保有量和交通流量的两种方法，分别估算出上海市年机动车NH3排放量为2.59和1.76 Gg，大大超过了中国排放动态预测模型的预测结果。鉴于这些发现，我们建议建立相关的国家标准和限制，以规范汽车NH3的排放是迫切和必要的。为了提高存货估计的准确性，应采用更有代表性的EFs计量方法。
Atmospheric ammonia (NH3) plays a significant role in the nitrogen cycle, and can have impacts on air quality, ecological balance and climate change. While NH3 associated with natural and agricultural processes has long been considered the primary source, the contribution of combustion-related NH3, particularly from vehicular emissions, keeps on the rise. We found that high on-road NH3 concentrations occurred in a metropolitan city based on mobile measurement, and inferred that urban vehicular NH3 emission was likely underestimated in the past. NH3 emission factors (EFs) were derived from ring roads and tunnels, showing levels 74% and 20% higher than the latest standard proposed by Euro VII, respectively. To quantify the underestimation, two methods based on car ownership and traffic flow were used to estimate the annual vehicular NH3 emission in Shanghai as 2.59 and 1.76 Gg, respectively, substantially surpassing the predicted results by the Dynamic Projection model for Emissions in China. Given these discoveries, we recommend that it is urgent and imperative to establish relevant national standards and limits aiming at regulation on vehicular NH3 emissions. And more representative EFs measurements should be adopted to improve the accuracy of inventory estimation.