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Nitrogen dioxide (NO2) is linked to poor air quality and severe human health impacts, including respiratory and cardiovascular diseases and being responsible annually for approximately 23,500 premature deaths in the UK. Automated air quality monitoring stations continuously record pollutants in urban environments but are restricted in number (need for electricity, maintenance and trained operators), only record air quality proximal to their location and cannot document variability of airborne pollutants at finer spatial scales. As an alternative, passive sampling devices such as Palmes-type diffusion tubes can be used to assess the spatial variability of air quality in greater detail, due to their simplicity (e.g. small, light material, no electricity required) and suitability for long-term studies (e.g. deployable in large numbers, useful for screening studies). Accordingly, a one passive diffusion tube sampling approach has been adapted to investigate spatial and temporal variability of NO2 concentrations across the City of Manchester (UK). Spatial and temporal detail was obtained by sampling 45 locations over a 12-month period (361 days, to include seasonal variability), resulting in 1080 individual NO2 measurements. Elevated NO2 concentrations, exceeding the EU/UK limit value of 40 µg m−3, were recorded throughout the study period (N = 278; 26% of individual measurements), particularly during colder months and across a wide area including residential locations. Of 45 sampling locations, 24% (N = 11) showed annual average NO2 above the EU/UK limit value, whereas 16% (N = 7) showed elevated NO2 (> 40 µg m−3) for at least 6 months of deployment. Highest NO2 was recorded in proximity of highly trafficked major roads, with urban factors such as surrounding building heights also influencing NO2 dispersion and distribution. This study demonstrates the importance of high spatial coverage to monitor atmospheric NO2 concentrations across urban environments, to aid identification of areas of human health concern, especially in areas that are not covered by automated monitoring stations. This simple, reasonably cheap, quick and easy method, using a single-NOx diffusion tube approach, can aid identification of NO2 hotspots and provides fine spatial detail of deteriorated air quality. Such an approach can be easily transferred to comparable urban environments to provide an initial screening tool for air quality and air pollution, particularly where local automated air quality monitoring stations are limited. Additionally, such an approach can support air quality assessment studies, e.g. lichen or moss biomonitoring studies. [ABSTRACT FROM AUTHOR]

The paleoceanographic history of the Pacific Ocean during the mid-Cretaceous is poorly constrained due to the loss of much of the contemporaneous Pacific seafloor to subduction and difficulties in recovering chert-rich sediments by ocean drilling. Pelagic sediments that were originally deposited in the Pacific Ocean but that have been subsequently accreted during subduction potentially provide an alternative paleoceanographic archive. This study presents micropaleontological and carbon-isotope data from the Calera Limestone, part of the classic Franciscan Complex exposed in Permanente Quarry, central California, USA. In the three stratigraphic sections studied, pelagic limestones with low organic-carbon contents are the dominant lithology. However, two stratigraphic intervals are recognized that contain organic carbon, and these date to the early Aptian and late Albian--early Cenomanian. These time intervals correspond to two mid-Cretaceous oceanic anoxic events (OAEs): early Aptian OAE1a (equivalent to the 'Selli level') and late Albian OAE1d (equivalent to the 'Breistroffer event'). It is well established that both of these events were associated with significant carbon-isotope excursions, which are also shown to exist in the Calera Limestone. The record of OAE1a from the Calera Limestone complements ocean drilling records by providing further evidence for variability in the sedimentary and stratigraphic record of this event. The carbon-isotope data from the late Albian--early Cenomanian provide the first detailed chemobiostratigraphic record of this period for the Pacific Ocean, confirming that environmental change occurred at this time in the Pacific, possibly related to OAE1d. Keywords: Cretaceous, oceanic anoxic events, carbon isotopes, Calera Limestone, paleoceanography.

A new composite [Delta]18O record, generated from calcareous fine-fraction and bulk sediments from the Exmouth Plateau, details long-term Cretaceous climatic change at mid-latitudes in the Southern Hemisphere. Assessment of new and previously published [Delta]18O data indicates that a mid-Cretaceous global climatic optimum was achieved sometime between the time of the Cenomanian-Turonian boundary and the middle Turonian, when surface-ocean paleotemperatures were the highest of the past 115 m.y. Periods of cooling and warming that reversed the general patterns were superimposed on long-term Aptian-Turonian warming and Turonian-Maastrichtian cooling trends, respectively. Extrapolation of Southern Hemisphere paleotemperature trends to Maastrichtian paleotemperature data from a low-latitude Pacific guyot implies that maximum mid-Cretaceous low-latitude paleotemperatures could have been in excess of 33 [degrees] C.

Abstract: The combined use of δ18O and another independent palaeotemperature proxy from the same carbonate biomineral archive forms the basis of a much desired palaeosalinity proxy by circumventing the main source of uncertainty in interpreting δ18O palaeorecords, i.e. variations in the isotopic composition of seawater. Contrary to the δ18O proxy, transferring the Mg/Ca–temperature proxy to marine bivalves has proved problematic, since a strong seawater temperature control on shell calcite Mg/Ca has rarely been observed. In this study, a preliminary evaluation of the combined use of δ18Ocalcite and Mg/Ca from Pecten maximus inner shell calcite to estimate δ18Owater is reported. New Mg/Ca data obtained by milling the inner shell regions from P. maximus specimens grown in laboratory aquaria under constant seawater temperatures between 10 and 20°C exhibit a strong relationship between Mg/Ca and temperature [Mg/Ca=2.56 (±0.42)+0.17 (±0.03)∗T, r2 =0.77, p<0.001, N=54], while the relationship between Sr/Ca and temperature was not strong (r2 =0.30, p<0.001, N=54). Using specimens grown in a separate aquaria validation experiment, estimated Mg/Ca-derived seawater temperature was within 0.48°C of measured seawater temperature, while estimated δ18Owater was within 0.05 to 0.15‰ of measured seawater δ18O composition, depending on the δ18O–temperature equation used, and with uncertainty estimates of 0.63‰ and 0.35‰. Such observations indicate the strongest potential to date for the development of valid temperature and δ18Owater/salinity proxies in bivalves from the combined application of Mg/Ca and δ18Ocalcite in the inner shell regions of P. maximus. Further studies for a wide range of pectinid species, ages and different natural environmental settings are needed to validate the observations of this study. [Copyright &y& Elsevier]

The ~35-m.y.-long Late Cretaceous greenhouse climate has been the subject of a number of studies, with emphasis on the Cenomanian-Turonian and late Campanian- Maastrichtian intervals. By contrast, far less information is available for the Turonian-early Campanian interval, even though it encompasses the transition out of the extreme warmth of the Cenomanian- Turonian greenhouse climate optimum and includes an ~3-m.y.-long mid-Coniacian- mid-Santonian interval when planktonic foraminifera underwent a large-scale, but poorly understood, turnover. This study presents ~1350 δ18O and δ13C values of wellpreserved benthic and planktonic foraminifera and of the <63 μm size fraction from the Exmouth Plateau off Australia (eastern Indian Ocean). These data provide: (1) the most continuous, highly resolved, and stratigraphically well-constrained record of longterm trends in Late Cretaceous oxygen- and carbon-isotope ratios from the southern midlatitudes, and (2) new information on the paleoecological preferences of planktonic foraminiferal taxa. The results indicate persistent warmth from the early Turonian until the mid-Santonian, cooling from the mid-Santonian through the mid-Campanian, and short-term climatic variability during the late Campanian-Maastrichtian. Moreover, our results suggest the cause of Coniacian- Santonian turnover among planktonic foraminifera may have been the diversification of a temperature- and/or salinity-tolerant genus (Marginotruncana), and the cause of the Santonian-early Campanian extinction of Dicarinella and Marginotruncana may have been surface-ocean cooling and competition with globotruncanids. [ABSTRACT FROM AUTHOR]

Presents the evidence of extreme Palaeogene-Cretaceous climates and extraterrestrial events of Black Nose. Collection of geological records to describe extreme warm climates; Transition of the Pelaeocene-Eocene; Recovery of Cretaceous-Tertiary boundary sections.