Strong Temperature Dependence for Light-Duty Diesel Vehicle NOx Emissions
Strong Temperature Dependence for Light-Duty Diesel Vehicle NOx Emissions
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DOI：
10.1021/acs.est.9b01024
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发表时间：
2019-06-04
影响因子：
11.4
通讯作者：
Carslaw, David C.
中科院分区：
文献类型：
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作者：
Grange, Stuart K.;Farren, Naomi J.;Carslaw, David C.
柴油动力道路车辆是氮氧化物（NOx）排放的重要来源，并且欧洲客运车队高度柴油化，这导致许多欧洲路边环境不符合二氧化氮（NO2）的法律的空气质量标准。根据英国30万辆轻型车辆的车辆排放遥感数据，发现轻型柴油机NOx排放高度依赖于环境温度，低温导致NOx排放较高，即，确定了“低温NOx排放损失”。汽油动力车辆没有观察到这一特征。较旧的欧盟3至5期柴油车辆排放的氮氧化物类似，但符合最新的欧盟6期排放标准的车辆排放的氮氧化物比较旧的车辆少，并且表现出较少的环境温度依赖性。这种对环境温度的依赖性在目前的排放清单中被忽视，但从空气质量的角度来看是重要的。由于欧洲的气候，与实验室测试循环中遇到的温度相比，预计平均38%以上的NOx排放量给欧洲带来了负担。然而，由于逐步淘汰表现出最严重的低温氮氧化物损失的车辆，轻型柴油机氮氧化物排放量在整个欧洲的下降速度可能比目前认为的要快。
Diesel-powered road vehicles are important sources for nitrogen oxide (NOx) emissions, and the European passenger fleet is highly dieselised, which has resulted in many European roadside environments being noncompliant with legal air quality standards for nitrogen dioxide (NO2). On the basis of vehicle emission remote sensing data for 300000 light-duty vehicles across the United Kingdom, light-duty diesel NOx emissions were found to be highly dependent on ambient temperature with low temperatures resulting in higher NOx emissions, i.e., a "low temperature NOx emission penalty" was identified. This feature was not observed for gasoline-powered vehicles. Older Euro 3 to 5 diesel vehicles emitted NOx similarly, but vehicles compliant with the latest Euro 6 emission standard emitted less NOx than older vehicles and demonstrated less of an ambient temperature dependence. This ambient temperature dependence is overlooked in current emission inventories but is of importance from an air quality perspective. Owing to Europe's climate, a predicted average of 38% more NOx emissions have burdened Europe when compared to temperatures encountered in laboratory test cycles. However, owing to the progressive elimination of vehicles demonstrating the most severe low temperature NOx penalty, light-duty diesel NOx emissions are likely to decrease more rapidly throughout Europe than currently thought.