The release of toxic atmospheric pollutants since the Industrial Revolution is a major global challenge, driving climate change and damaging human health. Spatial health inequalities highlight the need to explore air pollution in different localities throughout the Anthropocene. Air quality monitoring programmes are spatially and temporally limited. We show how suitable urban sediment archives provide site specific records of long-term particulate matter (PM) releases, in cities and urban landscapes, that are or have been subjected to high pollution levels. High-resolution PM records spanning from the mid-20th century were reconstructed from an urban pond in Chongqing, southwest China, one of the fastest growing Chinese urban centres in the late 20th century. Temporal variations in pollution proxies including geomagnetic, geochemical and spheroidal carbonaceous particle trends correspond to key phases of industrial and urban developments, that are representative of the locality. Observed increases in air pollution proxies post-1960 coincide with the location of military-related industries to Chongqing and industrial intensification. Post-1997 pollution mirrors rapid urbanisation that occurred following the designation of Chongqing as a government-controlled municipality at this time and reveals a steadily increasing pollution trend to present day (2015). In comparison to Chongqing, an atmospheric depositional history was constructed from an urban pond in the Merseyside region of northwest England that has experienced a legacy of contamination since the early 19th century. In northwest England, changing characteristics of pollution are related to the establishment of localised, modern industries, power generation, urban sprawl, increased combustion-derived pollution post-1990 and effective pollution legislations. Whereas a reduction in air pollution has occurred post-2000 in Merseyside, in Chongqing, however, air pollution has continued to increase in spite of national efforts in pollution control. These urban sediments reveal the changing nature of air pollution in different urban landscapes, allowing us to assess air quality impacts of progressive industrial activity, increased road and air travel, urban expansion and the efficacy of pollution controls. It appears that air pollution remains an inevitable consequence of global industrialisation. It is therefore crucial to understand pollution histories in densely populated urban regions to determine environmental burdens of pollution on health over generational timescales.

Bacteria modify their morphology in response to various factors including growth stage, nutrient availability, predation, motility and long-term survival strategies. Morphological changes may also be associated with specific physiological phenotypes such as the formation of dormant or persister cells in a “viable but non-culturable” (VBNC) state which frequently display different shapes and size compared to their active counterparts. Such dormancy phenotypes can display various degrees of tolerance to antibiotics and therefore a detailed understanding of these phenotypes is crucial for combatting chronic infections and associated diseases. Cell shape and size are therefore more than simple phenotypic characteristics; they are important physiological properties for understanding bacterial life-strategies and pathologies. However, quantitative studies on the changes to cell morphologies during bacterial growth, persister cell formation and the VBNC state are few and severely constrained by current limitations in the most used investigative techniques of flow cytometry (FC) and light or electron microscopy. In this study, we applied high-throughput Imaging Flow Cytometry (IFC) to characterise and quantify, at single-cell level and over time, the phenotypic heterogeneity and morphological changes in cultured populations of four bacterial species, Bacillus subtilis, Lactiplantibacillus plantarum, Pediococcus acidilactici and Escherichia coli. Morphologies in relation to growth stage and stress responses, cell integrity and metabolic activity were analysed. Additionally, we were able to identify and morphologically classify dormant cell phenotypes such as VBNC cells and monitor the resuscitation of persister cells in Escherichia coli following antibiotic treatment. We therefore demonstrate that IFC, with its high-throughput data collection and image capture capabilities, provides a platform by which a detailed understanding of changes in bacterial phenotypes and their physiological implications may be accurately monitored and quantified, leading to a better understanding of the role of phenotypic heterogeneity in the dynamic microbiome.

Atmospheric particulate matter (PM) causes 3.7 million annual deaths worldwide and potentially damages every organ in the body. The cancer-causing potential of fine particulates (PM_2.5) highlights the inextricable link between air quality and human health. With over half of the world’s population living in cities, PM_2.5emissions are a major concern, however, our understanding of exposure to urban PM is restricted to relatively recent (post-1990) air quality monitoring programmes. To investigate how the composition and toxicity of PM has varied within an urban region, over timescales encompassing changing patterns of industrialisation and urbanisation, we reconstructed air pollution records spanning 200 years from the sediments of urban ponds in Merseyside (NW England), a heartland of urbanisation since the Industrial Revolution. These archives of urban environmental change across the region demonstrate a key shift in PM emissions from coarse carbonaceous ‘soot’ that peaked during the mid-twentieth century, to finer combustion-derived PM_2.5post-1980, mirroring changes in urban infrastructure. The evolution of urban pollution to a recent enhanced PM_2.5signal has important implications for understanding lifetime pollution exposures for urban populations over generational timescales.

Summary: Pollen and tracheophyte spores are ubiquitous environmental indicators at local and global scales. Palynology is typically performed manually by microscopic analysis; a specialised and time‐consuming task limited in taxonomical precision and sampling frequency, therefore restricting data quality used to inform climate change and pollen forecasting models. We build on the growing work using AI (artificial intelligence) for automated pollen classification to design a flexible network that can deal with the uncertainty of broad‐scale environmental applications. We combined imaging flow cytometry with Guided Deep Learning to identify and accurately categorise pollen in environmental samples; here, pollen grains captured withinc.5500 Cal yr BP old lake sediments. Our network discriminates not only pollen included in training libraries to the species level but, depending on the sample, can classify previously unseen pollen to the likely phylogenetic order, family and even genus. Our approach offers valuable insights into the development of a widely transferable, rapid and accurate exploratory tool for pollen classification in ‘real‐world’ environmental samples with improved accuracy over pure deep learning techniques. This work has the potential to revolutionise many aspects of palynology, allowing a more detailed spatial and temporal understanding of pollen in the environment with improved taxonomical resolution.

Objective: Extracellular vesicles (EVs) facilitate molecular transport across extracellular space, allowing local and systemic signalling during homeostasis and in disease. Extensive studies have described functional roles for EV populations, including during cardiovascular disease, but the in vivo characterisation of endogenously produced EVs is still in its infancy. Due to their genetic tractability and opportunities for live imaging, zebrafish represent an ideal but under-used model to investigate endogenous EVs. The overall aim of this study was to establish a transgenic zebrafish model to allow the in vivo identification, tracking and extraction of endogenous EVs produced by different cell types. Approach and Results: Using a membrane-tethered fluorophore reporter system, we show that EVs can be fluorescently labelled in larval and adult zebrafish and demonstrate that multiple cell types including endothelial cells and cardiomyocytes actively produce EVs in vivo . Cell-type specific EVs can be tracked by high spatiotemporal resolution light-sheet live imaging and modified flow cytometry methods allow these EVs to be further evaluated. Importantly, we demonstrate the utility of this model by showing that cardiomyocytes, endothelial cells and macrophages exchange EVs in the adult heart and that ischaemic injury models dynamically alter EV production. Conclusions: We have developed a powerful in vivo zebrafish model for the investigation of endogenous EVs in all aspects of cardiovascular biology and pathology. A cell membrane fluorophore labelling approach allows cell type-specific tracing of EV origin without bias towards the expression of individual protein markers and will allow detailed future examination of their function.