Size-fractionated samples of airborne particulate matter have been collected in a number of campaigns at Marylebone Road, London and simultaneously at background sites either in Regents Park or at North Kensington. Analysis of these samples has enabled size distributions of total mass and of a number of elements to be determined, and roadside increments attributable to nonexhaust emissions arising from traffic activity have been calculated. Taking a novel approach, the combined use of size distribution information and tracer elements has allowed the separate estimation of the contributions of brake dust, tire dust, and resuspension to particle mass in the range 0.9-11.5 μm aerodynamic diameter and mean contributions (± s.e.) at the Marylebone Road sampling site are estimated as resuspended dust 38.1 ± 9.7%, brake dust 55.3 ± 7.0%, and tire dust 10.7 ± 2.3%, (accounting for a total of 104.1% of coarse particle mass in the traffic increment above background).

Advances of nanoscale science have produced nanomaterials with unique physical and chemical properties at commercial levels which are now incorporated into over 1000 products. Nanoscale cerium (di) oxide (CeO(2)) has recently gained a wide range of applications which includes coatings, electronics, biomedical, energy and fuel additives. Many applications of engineered CeO(2) nanoparticles are dispersive in nature increasing the risk of exposure and interactions with a variety of environmental media with unknown health, safety and environmental implications. As evident from a risk assessment perspective, the health effects of CeO(2) nanoparticles are not only dependent on their intrinsic toxicity but also on the level of exposure to these novel materials. Although this may seem logical, numerous studies have assessed the health effects of nanoparticles without this simple but critical risk assessment perspective. This review extends previous exposure and toxicological assessments for CeO(2) particles by summarizing the current state of micro and nano-scale cerium exposure and health risks derived from epidemiology, air quality monitoring, fuel combustion and toxicological studies to serve as a contemporary comprehensive and integrated toxicological assessment. Based on the new information presented in this review there is an ongoing exposure to a large population to new diesel emissions generated using fuel additives containing CeO2 nanoparticles for which the environmental (air quality and climate change) and public health impacts of this new technology are not known. Therefore, there is an absolute critical need for integrated exposure and toxicological studies in order to accurately assess the environmental, ecological and health implications of nanotechnology enabled diesel fuel additives with existing as well as new engine designs and fuel formulations.

Highlights d Cities possess a consistent ''core'' set of non-human microbes d Urban microbiomes echo important features of cities and city-life d Antimicrobial resistance genes are widespread in cities d Cities contain many novel bacterial and viral species

Protected areas vary enormously in their contribution to conserving biodiversity, and the inefficiency of protected area systems is widely acknowledged. However, conservation plans focus overwhelmingly on adding new sites to current protected area estates. Here we show that the conservation performance of a protected area system can be radically improved, without extra expenditure, by replacing a small number of protected areas with new ones that achieve more for conservation. Replacing the least cost-effective 1% of Australia's 6,990 strictly protected areas could increase the number of vegetation types that have 15% or more of their original extent protected from 18 to 54, of a maximum possible of 58. Moreover, it increases markedly the area that can be protected, with no increase in overall spending. This new paradigm for protected area system expansion could yield huge improvements to global conservation at a time when competition for land is increasingly intense.

Abstract. As part of the European ACTRIS project, the first large Quadrupole Aerosol Chemical Speciation Monitor (Q-ACSM) intercomparison study was conducted in the region of Paris for 3 weeks during the late-fall -early-winter period (November-December 2013). The first week was dedicated to the tuning and calibration of each instrument, whereas the second and third were dedicated to side-by-side comparison in ambient conditions with co-located instruments providing independent information on submicron aerosol optical, physical, and chemical properties. Near real-time measurements of the major chemical species (organic matter, sulfate, nitrate, ammonium, and chloride) in the non-refractory submicron aerosols (NR-PM 1 ) were obtained here from 13 Q-ACSM. The results show that these instruments can produce highly comparable and robust measurements of the NR-PM 1 total mass and its major components. Taking the median of the 13 Q-ACSM as a reference for this study, strong correlations (r 2 > 0.9) were observed systematically for each individual Q-ACSM across all chemical families except for chloride for which three Q-ACSMs showing weak correlations partly due to the very low concentrations during the study. Reproducibility expanded uncertainties of Q-ACSM concentration measurements were determined using appropriate methodologies defined by the International Standard Organization (ISO 17025, 1999) and were found to be 9, 15, 19, 28, and 36 % for NR-PM 1 , nitrate, organic matter, sulfate, and ammonium, respectively. However, discrepancies were observed in the relative concentrations of the constituent mass fragments for each chemical component. In particular, significant differences were observed for the organic fragment at mass-to-charge ratio 44, which is a key parameter describing the oxidation state of organic aerosol. Following this first major intercomparison exercise of a large number of Q-ACSMs, detailed intercomparison results are presented, along with a discussion of some recommendations about best calibration practices, standardized data processing, and data treatment.