Characterization of particulate matter concentrations during controlled indoor activities

Indoor sources have been identified as a major contributor to the increase of particle concentration in indoor environments. The work presented here is a study of the characteristics of particulate matter number size distribution and mass concentration under controlled indoor activities in a laboratory room. The objective is to characterize particulate matter concentrations indoors resulted under the influence of specific sources. Measurements were performed in an empty laboratory (period September–October 2006) using a GRIMM SMPS+C system (particle size range between 11.1 and 1083.3 nm), a DustTrak Aerosol Monitor (TSI) and a P-Trak Ultrafine Particle Counter (TSI). The studied indoor activities included candle burning, hot plate heating, water boiling, onion frying, vacuuming, hair drying, hair spraying, smoking and burning of incense stick. The AMANpsd computer algorithm was used to evaluate the modal structure of measured particle number size distribution data. Furthermore, the change of the particle number size distribution shape under the influence of different emission sources was studied versus time. Finally the particle emission rates were computed. High particle number concentrations were observed during smoking, onion frying, candle burning and incense stick burning. The highest particle mass concentrations were measured during smoking and hair spraying. The shift of the particle size distribution to larger diameters suggests the presence of strong coagulation effect during candle burning, incense stick burning, smoking and onion frying. The size distribution was mainly bimodal during onion frying and candle burning, whereas the size distribution remained unimodal during incense stick burning and smoking experiments.     

The Value of Using Feasibility Models in Systematic Conservation Planning to Predict Landholder Management Uptake

Understanding the social dimensions of conservation opportunity is crucial for conservation planning in multiple‐use landscapes. However, factors that influence the feasibility of implementing conservation actions, such as the history of landscape management, and landholders’ willingness to engage are often difficult or time consuming to quantify and rarely incorporated into planning. We examined how conservation agencies could reduce costs of acquiring such data by developing predictive models of management feasibility parameterized with social and biophysical factors likely to influence landholders’ decisions to engage in management. To test the utility of our best‐supported model, we developed 4 alternative investment scenarios based on different input data for conservation planning: social data only; biological data only; potential conservation opportunity derived from modeled feasibility that incurs no social data collection costs; and existing conservation opportunity derived from feasibility data that incurred collection costs. Using spatially explicit information on biodiversity values, feasibility, and management costs, we prioritized locations in southwest Australia to control an invasive predator that is detrimental to both agriculture and natural ecosystems: the red fox (Vulpes vulpes). When social data collection costs were moderate to high, the most cost‐effective investment scenario resulted from a predictive model of feasibility. Combining empirical feasibility data with biological data was more cost‐effective for prioritizing management when social data collection costs were low (<4% of the total budget). Calls for more data to inform conservation planning should take into account the costs and benefits of collecting and using social data to ensure that limited funding for conservation is spent in the most cost‐efficient and effective manner.     

Urinary stones as a novel matrix for human biomonitoring of toxic and essential elements

Monitoring of body burden of toxic elements is usually based on analysis of concentration of particular elements in blood, urine and/or hair. Analysis of these matrices, however, predominantly reflects short- or medium-term exposure to trace elements or pollutants. In this work, urinary stones were investigated as a matrix for monitoring long-term exposure to toxic and essential elements. A total of 431 samples of urinary calculi were subjected to mineralogical and elemental analysis by infrared spectroscopy and inductively coupled plasma mass spectrometry. The effect of mineralogical composition of the stones and other parameters such as sex, age and geographical location on contents of trace and minor elements is presented. Our results demonstrate the applicability of such approach and confirm that the analysis of urinary calculi can be helpful in providing complementary information on human exposure to trace metals and their excretion. Analysis of whewellite stones (calcium oxalate monohydrate) with content of phosphorus <0.6 % has been proved to be a promising tool for biomonitoring of trace and minor elements.

     

Geochemical distribution,bioavailability and potential toxicity of some trace metals in a complex micro-tidal estuary,Southwest India

The spatial and temporal variations of some trace metals in the surface sediments of Cochin Estuary were analyzed along with their geochemical associations to identify the possible sources, bioavailability and the health risks posed by them. The dominance of kaolinite and suggested that clay minerals distribution is influenced by sediment sorting. Total metal analysis revealed enrichment for Cd, Pb and Zn due to anthropogenic activities. The speciation analysis established that notwithstanding the large availability, carbonate as well as organic and sulfides bound fractions showed negligible associations with most of the metals. Hydrous Fe–Mn oxides appeared to play a major role in controlling the fate and transport of these metals in the sediments of Cochin Estuary. Lower contribution of the residual fractions for Cd (21%–26%), Pb (<60%) and Zn (24%–42%) indicated an obvious increase of other geochemical fractions. Risk assessment analysis revealed that regardless of total concentration, none of the analyzed metals were at safe levels in the estuary as appreciable percentages were found to be associated with mobile geochemical forms. The speciation study conspicuously established that the metals originating from non-geogenic sources are largely associated with the labile fractions and hence are more detrimental to the aquatic biota.     

Quantifying population declines based on presence‐only records for red‐list assessments

Accurate trend estimates are necessary for understanding which species are declining and which are most in need of conservation action. Imperfect species detection may result in unreliable trend estimates because this may lead to the overestimation of declines. Because many management decisions are based on population trend estimates, such biases could have severe consequences for conservation policy. We used an occupancy‐modeling framework to estimate detectability and calculate nationwide population trends for 14 Swiss amphibian species both accounting for and ignoring imperfect detection. Through the application of International Union for Conservation of Nature Red List criteria to the different trend estimates, we assessed whether ignoring imperfect detection could affect conservation policy. Imperfect detection occurred for all species and detection varied substantially among species, which led to the overestimation of population declines when detectability was ignored. Consequently, accounting for imperfect detection lowered the red‐list risk category for 5 of the 14 species assessed. We demonstrate that failing to consider species detectability can have serious consequences for species management and that occupancy modeling provides a flexible framework to account for observation bias and improve assessments of conservation status. A problem inherent to most historical records is that they contain presence‐only data from which only relative declines can be estimated. A move toward the routine recording of nonobservation and absence data is essential if conservation practitioners are to move beyond this toward accurate population trend estimation.     

The role of digital data entry in participatory environmental monitoring

Many argue that monitoring conducted exclusively by scientists is insufficient to address ongoing environmental challenges. One solution entails the use of mobile digital devices in participatory monitoring (PM) programs. But how digital data entry affects programs with varying levels of stakeholder participation, from nonscientists collecting field data to nonscientists administering every step of a monitoring program, remains unclear. We reviewed the successes, in terms of management interventions and sustainability, of 107 monitoring programs described in the literature (hereafter programs) and compared these with case studies from our PM experiences in Australia, Canada, Ethiopia, Ghana, Greenland, and Vietnam (hereafter cases). Our literature review showed that participatory programs were less likely to use digital devices, and 2 of our 3 more participatory cases were also slow to adopt digital data entry. Programs that were participatory and used digital devices were more likely to report management actions, which was consistent with cases in Ethiopia, Greenland, and Australia. Programs engaging volunteers were more frequently reported as ongoing, but those involving digital data entry were less often sustained when data collectors were volunteers. For the Vietnamese and Canadian cases, sustainability was undermined by a mismatch in stakeholder objectives. In the Ghanaian case, complex field protocols diminished monitoring sustainability. Innovative technologies attract interest, but the foundation of effective participatory adaptive monitoring depends more on collaboratively defined questions, objectives, conceptual models, and monitoring approaches. When this foundation is built through effective partnerships, digital data entry can enable the collection of more data of higher quality. Without this foundation, or when implemented ineffectively or unnecessarily, digital data entry can be an additional expense that distracts from core monitoring objectives and undermines project sustainability. The appropriate role of digital data entry in PM likely depends more on the context in which it is used and less on the technology itself.     

Molten carbonate fuel cells fed with biogas: Combating H2S

The use of biomass and waste to produce alternative fuels, due to environmental and energy security reasons, is a high-quality solution especially when integrated with high efficiency fuel cell applications. In this article we look into the coupling of an anaerobic digestion process of organic residues to electrochemical conversion to electricity and heat through a molten carbonate fuel cell (MCFC). In particular the pathway of the exceedingly harmful compound hydrogen sulphide (H₂S) in these phases is analysed. Hydrogen sulphide production in the biogas is strongly interrelated with methane and/or hydrogen yield, as well as with operating conditions like temperature and pH. When present in the produced biogas, this compound has multiple negative effects on the performance and durability of an MCFC. Therefore, there are important issues of integration to be solved.Three general approaches to solve the sulphur problem in the MCFC are possible. The first is to prevent the formation of hydrogen sulphide at the source: favouring conditions that inhibit its production during fermentation. Secondly, to identify the sulphur tolerance levels of the fuel cell components currently in use and develop sulphur-tolerant components that show long-term electrochemical performance and corrosion stability. The third approach is to remove the generated sulphur species to very low levels before the gas enters the fuel cell.