Intermediate volatility organic compound (IVOC) emissions from a large cargo vessel were characterized under realworld operating conditions using an on-board measurement system. Test ship fuel-based emission factors (EFs) of total IVOCs were determined for two fuel types and seven operating conditions. The average total IVOC EF was 1003 ± 581 mg•kg-fuel −1 , approximately 0.76 and 0.29 times the EFs of primary organic aerosol (POA) emissions from low-sulfur fuel (LSF, 0.38 wt % S) and high-sulfur fuel (HSF, 1.12 wt % S), respectively. The average total IVOC EF from LSF was 2.4 times that from HSF. The average IVOC EF under low engine load (15%) was 0.5−1.6 times higher than those under 36%−74% loads. An unresolved complex mixture (UCM) contributed 86.1 ± 1.9% of the total IVOC emissions. Ship secondary organic aerosol (SOA) production was estimated to be 546.5 ± 284.1 mg•kg-fuel −1 ; IVOCs contributed 98.9 ± 0.9% of the produced SOA on average. Fuel type was the dominant determinant of ship IVOC emissions, IVOC volatility distributions, and SOA production. The ship emitted more IVOC mass, produced higher proportions of volatile organic components, and produced more SOA mass when fueled with LSF than when fueled with HSF. When reducing ship POA emissions, more attention should be paid to commensurate control of ship SOA formation potential.

During the COVID-19 lockdown period (from January 23 to February 29, 2020), ambient PM 2.5 concentrations in the Yangtze River Delta (YRD) region were observed to be much lower, while the maximum daily 8 h average (MDA8) O 3 concentrations became much higher compared to those before the lockdown (from January 1 to 22, 2020). Here, we show that emission reduction is the major driving force for the PM 2.5 change, contributing to a PM 2.5 decrease by 37% to 55% in the four YRD major cities (i.e., Shanghai, Hangzhou, Nanjing, and Hefei), but the MDA8 O 3 increase is driven by both emission reduction (29%–52%) and variation in meteorological conditions (17%– 49%). Among all pollutants, reduction in emissions mainly of primary PM contributes to a PM 2.5 decrease by 28% to 46%, and NOx emission reduction contributes 7% to 10%. Although NOx emission reduction dominates the MDA8 O 3 increase (38%–59%), volatile organic compounds (VOCs) emission reduction lead to a 5% to 9% MDA8 O 3 decrease. Increased O 3 promotes secondary aerosol formation and partially offsets the decrease of PM 2.5 caused by the primary PM emission reductions. The results demonstrate that more coordinated air pollution control strategies are needed in YRD.

Streptomyces bingchenggensis is a soil-dwelling bacterium producing the commercially important anthelmintic macrolide milbemycins. Besides milbemycins, the insecticidal polyether antibiotic nanchangmycin and some other antibiotics have also been isolated from this strain. Here we report the complete genome sequence of S. bingchenggensis. The availability of the genome sequence of S. bingchenggensis should enable us to understand the biosynthesis of these structurally intricate antibiotics better and facilitate rational improvement of this strain to increase their titers.

Abstract. This study investigates the evolution of shipemitted aerosol particles using the stochastic particleresolved model PartMC-MOSAIC (Particle Monte Carlo model-Model for Simulating Aerosol Interactions and Chemistry). Comparisons of our results with observations from the QUANTIFY (Quantifying the Climate Impact of Global and European Transport Systems) study in 2007 in the English Channel and the Gulf of Biscay showed that the model was able to reproduce the observed evolution of total number concentration and the vanishing of the nucleation mode consisting of sulfate particles. Further process analysis revealed that during the first hour after emission, dilution reduced the total number concentration by four orders of magnitude, while coagulation reduced it by an additional order of magnitude. Neglecting coagulation resulted in an overprediction of more than one order of magnitude in the number concentration of particles smaller than 40 nm at a plume age of 100 s. Coagulation also significantly altered the mixing state of the particles, leading to a continuum of internal mixtures of sulfate and black carbon. The impact on cloud condensation nuclei (CCN) concentrations depended on the supersaturation threshold S at which CCN activity was evaluated. For the base case conditions, characterized by a low formation rate of secondary aerosol species, neglecting coagulation, but simulating condensation, led to an underestimation of CCN concentrations of about 37 % for S = 0.3 % at the end of the 14-h simulation. In contrast, for supersaturations higher than 0.7 %, neglecting coagulation resulted in an overestimation of CCN concentration, about 75 % for S = 1 %. For S lower than 0.2 % the differences between simulations including coagulation and neglecting coagulation were negligible. Neglecting condensation, but simulating coagulation did not impact the CCN concentrations below 0.2 % and resulted in an underestimation of CCN concentrations for larger supersaturations, e.g., 18 % for S = 0.6 %. We also explored the role of nucleation for the CCN concentrations in the ship plume. For the base case the impact of nucleation on CCN concentrations was limited, but for a sensitivity case with higher formation rates of secondary aerosol over several hours, the CCN concentrations increased by an order of magnitude for supersaturation thresholds above 0.3 %.

The kinetics of sulfite oxidation in the magnesium-based wet flue gas desulfurization (FGD) process were investigated in a stirred bubbling reactor by varying the concentrations of MgSO 3 and MgSO 4 , pH, air flow and temperature. The reaction was found to be 0.88 order with respect to magnesium sulfite and the oxidation could reach the maximum rate when the pH value was close to 6.5. The mechanism of the oxidation was discussed, and it was concluded that the oxidation is controlled by diffusion of oxygen. These results would be useful for the design or process optimization of the magnesium-based wet FGD system.