Various shipping emissions controls have recently been implemented at both local and national scales. However, it is difficult to track the effect of these on PM2.5 levels, owing to the non-linear relationship that exists between changes in precursor emissions and PM components. Positive Matrix Factorisation (PMF) identifies that a switch to cleaner fuels since January 2020 results in considerable reductions in shipping-source-related PM2.5, especially sulphate aerosols and metals (V and Ni), not only at a port site but also at an urban background site. CMAQ sensitivity analysis reveals that the reduction of secondary inorganic aerosols (SIA) further extends to inland areas downwind from ports. In addition, mitigation of secondary organic aerosols (SOA) in coastal urban areas can be anticipated either from the results of receptor modelling or from CMAQ simulations. The results in this study show the possibility of obtaining human health benefits in coastal cities through shipping emission controls.

This study presents empirical evidence that dilute particle-polymer suspensions exhibit composition-dependent stress oscillations at constant shear rate. In ethanol/toluene co-solvent suspensions, an increase in the ethanol concentration promoted a transition of the particle-polymer suspension from a stable state, through an oscillating state with well-defined periodicity, toward an unstable mode with multiple frequency peaks. This transition corresponded to increases in the gyration radii of the polymer chains in the fluids. Furthermore, the opposite transition from an unstable state to stable states was observed with increasing polymer concentrations. In contrast, the extent of the transition was curtailed in cyclohexane/toluene suspension, in which both the shear stress and gyration radius remained constant with negligible dependence on the fluid composition. These facts indicate that the non-hydrodynamic deletion attractions among particles play a significant role in influencing the stress instability of polymer-particle suspensions. ExperimentalPoly(vinyl acetate) (PVAc, Alfa Aesar Co.) with a mass averaged molecular weight (M w ) of 50,000 was dissolved in a