Widespread missing super-emitters of nitrogen oxides across China inferred from year-round satellite observations.

Nitrogen oxides (NOx ≡ NO + NO2) play a central role in air pollution and are targeted for emission mitigation by environmental protection agencies globally. Unique challenges for mitigation are presented by super-emitters, typically with the potential to dominate localized NOx budgets. Nevertheless, identifying super-emitters still challenges emission mitigation, while the spatial resolution of emission monitoring rises continuously. Here we develop an efficient, super-resolution (1 × 1 km2) inverse model based on year-round TROPOMI satellite observations over China. Consequently, we resolve hundreds of super-emitters in virtually every corner of China, even in remote and mountainous areas. They are attributed to individual plants or parks, mostly associated with industrial sectors, like energy, petrochemical, and iron and steel industries. State-of-the-art bottom-up emission estimates (i.e., MEICv1.3 and HTAPv2), as well as classic top-down inverse methods (e.g., a CTM coupled with the Ensemble Kalman Filter), do not adequately identify these super-emitters. Remarkably, more than one hundred super-emitters are unambiguously missed, while the establishments or discontinuations of the super-emitters potentially lead to under- or over-estimates, respectively. Moreover, evidence shows that these super-emitters generally dominate the NOx budget in a localized area (e.g., equivalent to a spatial scale of a medium-sized county). Although our dataset is incomplete nationwide due to the undetectable super-emitters on top of high pollution, our results imply that super-emitters contribute significantly to national NOx budgets and thus suggest the necessity to address the NOx budget by revisiting super-emitters on a large scale. Integrating the results we obtain here with a multi-tiered observation system can lead to identification and mitigation of anomalous NOx emissions.

Comparative assessment of the effect of pretreatment with microwave and roast heating on the quality of black sesame pastes.

Heating is a key procedure in producing sesame paste. The effects of microwave heating and conventional roasting on the physicochemical features, protein profiles, and volatile compounds of black sesame pastes made of black sesame seeds from Burma and China were evaluated in this study. All heating treatments decreased the moisture contents of black sesame pastes, and roasting yielded lower moisture levels, although with similar chroma (p < 0.05). The samples subjected to microwave heating had remarkably lower peroxide values than those heated with roasting (p < 0.05). Chinese microwave-heated samples had a higher nitrogen solubility index than roasting (p < 0.05). Both microwave and roasting increased the contents of the volatiles notably. SDS-PAGE showed that the intensity of the 2-15 kDa band decreased markedly after heating and nearly diminished for roasting samples, suggesting that roasting was more remarkable for the promotion to the protein aggregation. The results indicated that the quality traits of black sesame paste not only depend on the heating methods, but also the heating power/temperature and duration, and the source of the materials.