Three-year observations of halocarbons at the Nepal Climate Observatory at Pyramid (NCO-P, 5079 m a.s.l.) on the Himalayan range

A monitoring programme for halogenated climate-altering gases has been established in the frame of the SHARE EV-K<sup>2</sup>-CNR project at the Nepal Climate Laboratory – Pyramid in the Himalayan range at the altitude of 5079 m a.s.l. The site is very well located to provide important insights on changes in atmospheric composition in a region that is of great significance for emissions of both anthropogenic and biogenic halogenated compounds. Measurements are performed since March 2006, with grab samples collected on a weekly basis. The first three years of data have been analysed. After the identification of the atmospheric background values for fourteen halocarbons, the frequency of occurrence of pollution events have been compared with the same kind of analysis for data collected at other global background stations. The analysis showed the fully halogenated species, whose production and consumption are regulated under the Montreal Protocol, show a significant occurrence of "above the baseline" values, as a consequence of their current use in the developing countries surrounding the region, meanwhile the hydrogenated gases, more recently introduced into the market, show less frequent spikes. <br><br> Atmospheric concentration trends have been calculated as well, and they showed a fast increase, ranging from 5.7 to 12.6%, of all the hydrogenated species, and a clear decrease of methyl chloroform (−17.7%). The comparison with time series from other stations has also allowed to derive Meridional gradients, which are absent for long living well mixed species, while for the more reactive species, the gradient increases inversely with respect to their atmospheric lifetime. The effect of long range transport and of local events on the atmospheric composition at the station has been analysed as well, allowing the identification of relevant source regions the Northern half of the Indian sub-continent. Also, at finer spatial scales, a smaller, local contribution of forest fires from the Khumbu valley has been detected

Seasonal budgets of ozone and oxidant precursors in an industrial coastal area of northern Italy

The seasonal budgets and evolution of photochemical oxidants reported for greater Ravenna's urban-industrial area in the present study were calculated using the combined data from on-site systematic surveys (1978-1989) and from the monitoring network of the local environmental authorities. The notable differences in the concentrations of ozone and nitrogen oxides depended on season, and meteorological variables showed a marked correlation to the seasonal budget of trace constituents. The weak local circulation, the land-sea breeze system, and high solar radiation in summer, which may persist at length because of the anticyclonic conditions, can produce episodes of intense photochemical reactions. In winter, by contrast, low solar radiation and the absence of the breeze system results in very different evolutions of both pollutant concentrations and their seasonal budget

Aerosol direct radiative effects under cloud-free conditions over highly-polluted areas in europe and mediterranean: A ten-years analysis (2007–2016)

This study investigates changes in aerosol radiative effects on two highly urbanized regions across the Euro-Mediterranean basin with respect to a natural desert region as Sahara over a decade through space-based lidar observations. The research is based on the monthly-averaged vertically-resolved aerosol optical depth (AOD) atmospheric profiles along a 1◦ × 1◦ horizontal grid, obtained from the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) instrument measurements aboard the Cloud-Aerosol lidar and Infrared Pathfinder Satellite Observation (CALIPSO). To assess the variability of the anthropogenic aerosols on climate, we compared the aerosol vertical profile observations to a one-dimensional radiative transfer model in two metropolitan climate sensible hot-spots in Europe, namely the Po Valley and Benelux, to investigate the variability of the aerosol radiative effects and heating rate over ten years. The same analysis is carried out as reference on the Sahara desert region, considered subject just to natural local emission. Our findings show the efficacy of emission reduction policies implemented at government level in strongly urbanized regions. The total atmospheric column aerosol load reduction (not observed in Sahara desert region) in Po Valley and Benelux can be associated with: (i) an increase of the energy flux at the surface via direct effects confirmed also by long term surface temperature observations, (ii) a general decrease of the atmospheric column heating rate, and likely (iii) an increase in surface temperatures during a ten-year period. Summarizing, the analysis, based on the decade 2007–2016, clearly show an increase of solar irradiation under cloud-free conditions at the surface of +3.6 % and +16.6% for the Po Valley and Benelux, respectively, and a reduction of −9.0% for the Sahara Desert

Aerosol mass and black carbon concentrations, a two year record at NCO-P (5079 m, Southern Himalayas)

Aerosol mass and the absorbing fraction are important variables, needed to constrain the role of atmospheric particles in the Earth radiation budget, both directly and indirectly through CCN activation. In particular, their monitoring in remote areas and mountain sites is essential for determining source regions, elucidating the mechanisms of long range transport of anthropogenic pollutants, and validating regional and global models. Since March 2006, aerosol mass and black carbon concentration have been monitored at the Nepal Climate Observatory-Pyramid, a permanent high-altitude research station located in the Khumbu valley at 5079 m a.s.l. below Mt. Everest. The first two-year averages of PM<sub>1</sub> and PM<sub>1−10</sub> mass were 1.94 μg m<sup>−3</sup> and 1.88 μg m<sup>−3</sup>, with standard deviations of 3.90 μg m<sup>−3</sup> and 4.45 μg m<sup>−3</sup>, respectively, while the black carbon concentration average is 160.5 ng m<sup>−3</sup>, with a standard deviation of 296.1 ng m<sup>−3</sup>. Both aerosol mass and black carbon show well defined annual cycles, with a maximum during the pre-monsoon season and a minimum during the monsoon. They also display a typical diurnal cycle during all the seasons, with the lowest particle concentration recorded during the night, and a considerable increase during the afternoon, revealing the major role played by thermal winds in influencing the behaviour of atmospheric compounds over the high Himalayas. The aerosol concentration is subject to high variability: in fact, as well as frequent "background conditions" (55% of the time) when BC concentrations are mainly below 100 ng m<sup>−3</sup>, concentrations up to 5 μg m<sup>−3</sup> are reached during some episodes (a few days every year) in the pre-monsoon seasons. The variability of PM and BC is the result of both short-term changes due to thermal wind development in the valley, and long-range transport/synoptic circulation. At NCO-P, higher concentrations of PM<sub>1</sub> and BC are mostly associated with regional circulation and westerly air masses from the Middle East, while the strongest contributions of mineral dust arrive from the Middle East and regional circulation, with a special contribution from North Africa and South-West Arabian Peninsula in post-monsoon and winter season

Ship-board report on atmospheric CO2 concentrations recorded on continuous from Mediterranean sea to Antarctica

We present the results obtained from continuous measurements performed during two cruises with hemispherical courses. In this way, we obtained the latitudinal trend of CO2 in continuity of space and time along two hemispheric courses in 1994-95 and 1996-97 from Europe to Antarctica. The results are compared with measurements from the National Oceanic and Atmospheric Administration (NOAA) Climate Monitoring and Diagnostic Laboratory (CMDL) cooperative air sampling network. The fitting of data recorded on board with the historical data sets recorded at Palmer Station is also presented, highlighting the current annual increase in atmospheric CO2 concentrations

Preliminary Estimation of Black Carbon Deposition from Nepal Climate Observatory-Pyramid Data and Its Possible Impact on Snow Albedo Changes Over Himalayan Glaciers During the Pre-Monsoon Season

The possible minimal range of reduction in snow surface albedo due to dry deposition of black carbon (BC) in the pre-monsoon period (March-May) was estimated as a lower bound together with the estimation of its accuracy, based on atmospheric observations at the Nepal Climate Observatory-Pyramid (NCO-P) sited at 5079 m a.s.l. in the Himalayan region. We estimated a total BC deposition rate of 2.89 g m-2 day-1 providing a total deposition of 266 micrograms/ square m for March-May at the site, based on a calculation with a minimal deposition velocity of 1.0 10(exp -4) m/s with atmospheric data of equivalent BC concentration. Main BC size at NCO-P site was determined as 103.1-669.8 nm by correlation analysis between equivalent BC concentration and particulate size distribution in the atmosphere. We also estimated BC deposition from the size distribution data and found that 8.7% of the estimated dry deposition corresponds to the estimated BC deposition from equivalent BC concentration data. If all the BC is deposited uniformly on the top 2-cm pure snow, the corresponding BC concentration is 26.0-68.2 microgram/kg assuming snow density variations of 195-512 kg/ cubic m of Yala Glacier close to NCO-P site. Such a concentration of BC in snow could result in 2.0-5.2% albedo reductions. From a simple numerical calculations and if assuming these albedo reductions continue throughout the year, this would lead to a runoff increases of 70-204 mm of water drainage equivalent of 11.6-33.9% of the annual discharge of a typical Tibetan glacier. Our estimates of BC concentration in snow surface for pre-monsoon season can be considered comparable to those at similar altitude in the Himalayan region, where glaciers and perpetual snow region starts in the vicinity of NCO-P. Our estimates from only BC are likely to represent a lower bound for snow albedo reductions, since a fixed slower deposition velocity was used and atmospheric wind and turbulence effects, snow aging, dust deposition, and snow albedo feedbacks were not considered. This study represents the first investigation about BC deposition on snow from atmospheric aerosol data in Himalayas and related albedo effect is especially the first track at the southern slope of Himalayas

Implementation of a webGIS service platform for high mountain climate research: the SHARE GeoNetwork project

The implementation of a webGIS service platform dedicated to the management and sharing of climatological data acquired by high elevation stations is the core of the Station at High Altitude for Research on the Environment (SHARE) GeoNetwork project, promoted by the Ev-K2 CNR Committee. The web platform basically will provide three types of services: structured metadata archive, data and results from high-altitude environments research and projects; access to high-altitude Ev-K2 CNR stations and creation of a network of existing stations; dedicated webGIS for geo-referenced data collected during the research. High elevation environmental and territorial data and metadata are catalogued in a single integrated platform to get access to the information heritage of the SHARE project, using open-source tools: Geonetwork for the metadata catalogue and webGIS resources, and the open-source Weather and Water Database (WDB), developed by the Norwegian Meteorological Institute, for the database information system implementation. The information system is designed to have a main node, with the possibility to install relocated subsystems based on the same technology, named focal point of SHARE, which will contain metadata and data connected to the main node. In this study, a new structure of metadata for the description of the climatological stations is proposed and WDB adaptation and data preprocessing are described in detail, giving code and script samples

Characterization of atmospheric aerosols at Monte Cimone, Italy, during summer 2004: Source apportionment and transport mechanisms

Atmospheric aerosols in the PM10 and PM1 fractions have been sampled at the Global Atmospheric Watch station Mount Cimone, Italy (2165 m above mean sea level) for 3 months during summer 2004, and simultaneous size distributions have been derived by means of an optical particle counter. Samples have been analyzed by X-ray fluorescence, ion chromatography, and thermal-optical methodology in order to quantify their elemental, ionic, and carbonaceous constituents. The concentration of PM10 was 16.1 \ub1 9.8 mg m3 (average and standard deviation). Source apportionment allowed us to identify, quantify and characterize the following aerosol classes: anthropogenic pollution (10 mg m3), mineral dust (4 mg m3), and sea salt (0.2 mg m3). Pollution has been further split into ammonium sulfate (44%), organic matter (42%), and other compounds (14%). The nitrate/sulfate ratio in the polluted aerosol was 0.1. Fine particles have been completely related to the polluted aerosol component, and they represented 70% in weight of pollution. Coarse particles characterized the dust and salt components, and crustal oxides have been found to be the largest responsible for the aerosol concentration variations that occurred during the campaign. Nitrate has also been found in the coarse particles, representing 10% of mineral dust. The analysis of the transport mechanisms responsible for aerosol fluctuations permitted us to identify the origin of the major aerosol components: Pollution has been ascribed to regional transport driven by boundary layer meteorology, whereas mineral dust has been related to long-range transport events originating in the Sahara and Sahel. A particularly significant Saharan episode has been identified on 10 August 2004 (PM10 daily concentration, 69.9 mg m3). Average elemental ratios for the African dust events were as follows: Si/Al = 2.31, Fe/Ca = 0.94, Ca/Al = 0.90, K/Ca = 0.44, Ti/Ca = 0.11, and Ti/Fe = 0.12

Mineral fibres and asbestos bodies in human lung tissue: A case study

One of the open questions regarding the asbestos problem is the fate of the mineral fibres in the body once inhaled and deposited in the deep respiratory system. In this context, the present paper reports the results of an electron microscopy study of both mineral fibres and asbestos bodies found in the lung tissue of a patient who died of malignant mesothelioma due to past occupational exposure. In concert with previous in vivo animal studies, our data provide evidence that amphibole asbestos fibres are durable in the lungs, whereas chrysotile fibres are transformed into a silica-rich product, which can be easily cleared. Amphibole fibres recovered from samples of tissue of the deceased display a high degree of crystallinity but also show a very thin amorphous layer on their surface; 31% of the fibres are coated with asbestos bodies consisting of a mixture of ferroproteins (mainly ferritin). Here, we propose an improved model for the coating process. Formation of a coating on the fibres is a defence mechanism against fibres that are longer than 10 µm and thinner than 0.5 µm, which macrophages cannot engulf. The mature asbestos bodies show signs of degradation, and the iron stored in ferritin may be released and potentially increase oxidative stress in the lung tissue