Comparative evaluation of four suspended particulate matter (SPM) sampling devices and their use for monitoring SPM quality

Environmental Science and Pollution Research - Representative sampling of suspended particulate matter is fundamental for assessing river sediment quality, including the distribution and...     

Revisiting nitrous acid (HONO) emission from on-road vehicles: A tunnel study with a mixed fleet

Nitrous acid (HONO) is an important precursor of OH radicals in the atmosphere. In urban areas, emissions from vehicles are the main source of air pollutants, including reactive nitrogen. Previously reported emission ratios of HONO (HONO/NO_x) from vehicles were measured in the late 1990s and need to be updated due to the significant changes in emission control technologies. We measured the emission ratio of a fleet of vehicles (38% diesel on average) from March 11 to 21, 2015, in a road tunnel in Hong Kong. The emission ratio of 1.24% (±0.35%) obtained is greater than the commonly adopted 0.8% or 0.3%. The elevated emission ratio is found to be related to the presence of vehicles equipped with diesel particle filters (DPFs). Positive correlation between HONO and black carbon (BC) shows that HONO and BC were emitted together, while the lack of correlation or even anticorrelation between HONO/NO_x and BC indicates that the BC-mediated conversion of NO₂ to HONO in the dark was insignificant in the immediate vicinity of the emission sources.

Implications: Vehicular emission is a key source for HONO in the urban atmosphere. However, the most commonly used emission ratio HONO/NO_x in modeling studies was measured more than 15 years ago. Our tunnel study suggests that a mixed fleet nowadays has a higher emission ratio, possibly because of the diesel particle filter (DPF) retrofit program and the growing share of Euro IV or more advanced diesel vehicles. Our study also provides new insight into the role of black carbon in HONO formation from vehicles.     

Measuring atmospheric composition change

Scientific findings from the last decades have clearly highlighted the need for a more comprehensive approach to atmospheric change processes. In fact, observation of atmospheric composition variables has been an important activity of atmospheric research that has developed instrumental tools (advanced analytical techniques) and platforms (instrumented passenger aircrafts, ground-based in situ and remote sensing stations, earth observation satellite instruments) providing essential information on the composition of the atmosphere. The variability of the atmospheric system and the extreme complexity of the atmospheric cycles for short-lived gaseous and aerosol species have led to the development of complex models to interpret observations, test our theoretical understanding of atmospheric chemistry and predict future atmospheric composition. The validation of numerical models requires accurate information concerning the variability of atmospheric composition for targeted species via comparison with observations and measurements.In this paper, we provide an overview of recent advances in instrumentation and methodologies for measuring atmospheric composition changes from space, aircraft and the surface as well as recent improvements in laboratory techniques that permitted scientific advance in the field of atmospheric chemistry. Emphasis is given to the most promising and innovative technologies that will become operational in the near future to improve knowledge of atmospheric composition. Our current observation capacity, however, is not satisfactory to understand and predict future atmospheric composition changes, in relation to predicted climate warming. Based on the limitation of the current European observing system, we address the major gaps in a second part of the paper to explain why further developments in current observation strategies are still needed to strengthen and optimise an observing system not only capable of responding to the requirements of atmospheric services but also to newly open scientific questions.     

GIS-basierte Modellierung von Gewässerimmissionen

Goal and Scope

Environmental assessment of aquatic micro pollutants should consider the spatial and temporal variability of emission, transport and transformation. Simulation models coupled with Geographic Information Systems (GIS) provide digital maps of concentration patterns caused by the overlay of multipoint and diffuse emissions and natural attenuation processes in river basins. The paper gives an overview on GIS-based models for river basins and demonstrates the applicability by using some illustrating examples with GREAT-ER.

Main Features

Georeferenced models have several advantages: visualization of concentration patterns, investigation of spatial and temporal concentration profiles, analysis of exceedance of environmental quality standards, embedding in integrated river basin management systems.

Results and Discussion

GIS-based models allow a more realistic assessment. Monitoring programmes should be designed to deliver appropriate measured data for the evaluation and improvement of models.

Recommendation and Perspectives

The combination of digital maps, simulation models and environmental monitoring would provide better approaches for the risk assessment and water quality management of aquatic micro pollutants.     

Enzymatic production of biosilica glass using enzymes from sponges: basic aspects and application in nanobiotechnology (material sciences and medicine)

Biomineralization, biosilicification in particular (i.e. the formation of biogenic silica, SiO₂), has become an exciting source of inspiration for the development of novel bionic approaches following “nature as model”. Siliceous sponges are unique among silica forming organisms in their ability to catalyze silica formation using a specific enzyme termed silicatein. In this study, we review the present state of knowledge on silicatein-mediated “biosilica” formation in marine sponges, the involvement of further molecules in silica metabolism and their potential application in nanobiotechnology and medicine. Werner E. G. Müller dedicated this study to Prof. Vera Gamulin (Rudjer Boskovic Institute, Zagreb, Croatia) in honour of her unique contributions in molecular evolution.     

民族性演艺建筑室内设计及其声学特性——以茂县羌族演艺中心为例

本文主要介绍茂县羌族演艺中心的功能及建筑概况,讨论观众厅内部主要装修材料的选用及声学设计要求。并思考如何使剧院更好地与当地建筑、文化相融合,赋予其一定的地域性、文化性和民族性。     

Role of nitric oxide in the genotoxic response to chronic microcystin-LR exposure in human–hamster hybrid cells

Microcystin-LR (MC-LR) is the most abundant and toxic microcystin congener and has been classified as a potential human carcinogen (Group 2B) by the International Agency for Research on Cancer. However, the mechanisms underlying the genotoxic effects of MC-LR during chronic exposure are still poorly understood. In the present study, human–hamster hybrid (A_L) cells were exposed to MC-LR for varying lengths of time to investigate the role of nitrogen radicals in MC-LR-induced genotoxicity. The mutagenic potential at the CD59 locus was more than 2-fold higher (p < 0.01) in A_L cells exposed to a cytotoxic concentration (1 μmol/L) of MC-LR for 30 days than in untreated control cells, which was consistent with the formation of micronucleus. MC-LR caused a dose-dependent increase in nitric oxide (NO) production in treated cells. Moreover, this was blocked by concurrent treatment with the NO synthase inhibitor N^G-methyl-l-arginine (l-NMMA), which suppressed MC-LR-induced mutations as well. The survival of mitochondrial DNA-depleted (ρ⁰) A_L cells was markedly decreased by MC-LR treatment compared to that in A_L cells, while the CD59 mutant fraction was unaltered. These results provided clear evidence that the genotoxicity associated with chronic MC-LR exposure in mammalian cells was mediated by NO and might be considered as a basis for the development of therapeutics that prevent carcinogenesis.