Quantification of ozone levels in indoor environments generated by ionization and ozonolysis air purifiers

Indoor air purifiers are advertised as safe household products for health-conscious individuals, especially for those suffering from allergies and asthma. However, certain air purifiers produce ozone (O3) during operation, either intentionally or as a byproduct of air ionization. This is a serious concern, because O3 is a criteria air pollutant regulated by health-related federal and state standards. Several types of air purifiers were tested for their ability to produce ozone in various indoor environments at 40-50% relative humidity, including office rooms, bathrooms, bedrooms, and cars. O3 levels generated by personal wearable air purifiers were also tested. In many cases, O3 concentrations were well in excess of public and/or industrial safety levels established by U.S. Environmental Protection Agency, California Air Resources Board, and Occupational Safety and Health Administration. Simple kinetic equations were obtained that can predict the steady-state level of O3 in a room from the O3 emission rate of the air purifier and the first-order decay rate of O3 in the room. The additivity of O3 levels generated by independent O3 generators was experimentally demonstrated.     

From authoritarian enclave to deliberative space: governance logics in post‐disaster reconstruction

One would be hard‐pressed nowadays to find any practitioners and scholars in the field of post‐disaster reconstruction who would argue against the virtues of community participation. In practice, however, the legacy of community participation has been mixed. This paper pursues this line of inquiry by examining the manifestations of participation in three communities affected by Typhoon Haiyan that struck the Philippines on 8 November 2013. The findings suggest that different governance logics emerge in each of the three case studies: authoritarian; communitarian; and deliberative. These logics promote particular understandings of who should participate in the reconstruction process and the appropriate scope of action for citizens to express discontent, provide feedback, and perform democratic agency. The paper contends that design interventions in participatory procedures, as well as contingencies in wider social contexts, shape the character and legacies of community participation. It concludes by comparing the legacies of these three ‘governance enclaves’ and imagining possibilities for participatory politics in post‐disaster settings.     

From the Editors

Editorial Introduction

From the Editors     

EVALUATION OF NITRATE DATA IN THE OCKLAWAHA RIVER BASIN,FLORIDA (1953–2002)1

ABSTRACT: Nitrate levels in the Ocklawaha River Basin in north central Florida were reviewed over a 50‐year period. Data were obtained from the literature, U.S. Environmental Protection Agency (USEPA) STOrage and RETrieval (STORET), and U.S. Geological Survey (USGS) databases. The study objective was to determine whether nitrate concentrations are increasing and if so, whether this increase is linked to land use changes. Increasing nitrate levels were seen at 5 of the 14 stations, while other stations showed no trend or a decreasing trend. Median nitrate concentrations in the Ocklawaha River increased from 0.07 mg‐N/L to 0.78 mg‐N/L at sites downstream from the Silver River. Throughout the Rodman Reservoir, median nitrate concentrations decreased from 0.48 mg‐N/L to 0.01 mg‐N/L and increased to 0.04 mg‐N/L after the Kirkpatrick Dam. Flow and concentration relationships were correlated for five stations. At four of the five stations nitrate concentrations decreased in response to increasing flow, likely the result of dilution with nitrate poor water. Changes in land use over a 20‐ year period (1970 to 1990) also were monitored. Sources of nitrate have been linked by isotopic analysis to organic and inorganic fertilizers, which appear to be related to increased urbanization and an increase in lawns that require nutrient fertilization.     

Identifying the sources and timing of ancient and medieval atmospheric lead pollution in England using a peat profile from Lindow bog, Manchester

A peat core from Lindow bog near Manchester, England, was precisely cut into 2 cm slices to provide a high-resolution reconstruction of atmospheric Pb deposition. Radiocarbon and (210)Pb age dates show that the peat core represents the period ca. 2000 BC to AD 1800. Eleven radiocarbon age dates of bulk peat samples reveal a linear age-depth relationship with an average temporal resolution of 18.5 years per cm, or 37 years per sample. Using the Pb/Ti ratio to calculate the rates of anthropogenic, atmospheric Pb deposition, the profile reveals Pb contamination first appearing in peat samples dating from ca. 900 BC which clearly pre-date Roman mining activities. Using TIMS, MC-ICP-MS, and SF-ICP-MS to measure the isotopic composition of Pb, the (208)Pb/(206)Pb and (206)Pb/(207)Pb data indicate that English ores were the predominant sources during the pre-Roman, Roman, and Medieval Periods. The study shows that detailed studies of peat profiles from ombrotrophic bogs, using appropriate preparatory and analytical methods, can provide new insight into the timing, intensity, and predominant sources of atmospheric Pb contamination, even in samples dating from ancient times.     

Validation of a conductometric bienzyme biosensor for the detection of proteins as marker of organic matter in river samples

This article describes a conductometric bi-layer based bienzyme biosensor for the detection of proteins as a marker of organic matter in rivers. Proteins were chosen to be used as indicators of urban pollution. The working mechanism of the bienzyme biosensor is based on the enzymatic hydrolysis of proteins into several fractions (peptides and amino acids), which results in a local conductivity change depending of the concentration of proteins. In this work, we began with the optimization of biosensor response using bovine serum albumin (BSA) as standard protein. For this objective seven enzymatic biosensors were prepared: four enzymatic sensors with only one layer of enzyme (proteinase K, trypsin, pronase or protease X) and three other enzymatic sensors with two layers (first layer: membrane containing proteinase K; second layer: one of the three other enzymes: trypsin, pronase or protease X). The biosensors were obtained through the deposition of enzymatic layers and the cross-linking process between enzymes and BSA in saturated glutaraldehyde vapour. The response of the various biosensors, described previously, were compared with the values of total organic carbon (TOC), and those of organic nitrogen (Norg), as determined by the laboratory accredits (CEMAGREF of Lyon) using the traditional method of analysis (NF EN 1484, infrared spectroscopy) and (NF EN 25663, mineralization/colorimetry assay) respectively for each water sample obtained from di erent sites in Lyon (France). The linear correlations obtained with the response of the seven biosensors showed the most important indices of correlations for the biosensor with two enzymatic layers: proteinase K + pronase (pkp). The optimum conditions for the preparation of the pkp biosensor increased the sensitivity and gave a limit of quantification of 0.583 g/L for TOC and 0.218 g/L for Norg in water samples. This sensor shows good reproducibility (2.28%), a capacity to be used at temperatures range 10– 30°C (depending on the season) and moreover a long lifetime (5 weeks).     

Climate change adaptation strategies in the Mekong and Orange-Senqu basins: What determines the state-of-play?

The challenge of governing transboundary water resources is expected to increase with climate change and the resulting need to adapt to its impacts such as temperature increase, more precipitation in the wet season and less in the dry season. In a number of transboundary basins, international regimes, and in particular river basin commissions, are emerging to account for this and other challenges. Some basins are, however, rather advanced in terms of developing climate change adaptation strategies, while others are in a more nascent stage. For the two case studies of the Orange-Senqu and Mekong river basins, this paper attempts to explain the different degrees of progress towards climate change adaptation by applying regime effectiveness analysis. First, we analyze, using the Activity Diagram (AD) of the Management and Transition Framework (MTF), at which stage in the climate change adaptation policy formation process each of the two basins is. Then we attempt to explain the different degrees of progress towards adaptation by means of regime effectiveness theory. Variables indicating regime effectiveness are taken from the literature and further developed to suit the context of climate change adaptation. We find that the different degrees of progress can partially be explained by some variables of regime effectiveness such as the characteristics of rules and procedures, organizational structure, the role of riparian countries as well as international context. At the same time, the analysis points to the need for an analysis of additional factors that potentially shape decision-making and policy processes for climate change adaptation in international river basins such as (a) the hydrological, political and socio-economic setting, (b) underlying principles of regional cooperation (or conflict), (c) interests and values of the various actors in the negotiation process and (d) the possible linkages and trade-offs with other policy fields.     

The Baltic Sea spring phytoplankton bloom in a changing climate: an experimental approach

The response of the Baltic Sea spring bloom was studied in mesocosm experiments, where temperatures were elevated up to 6°C above the present-day sea surface temperature of the spring bloom season. Four of the seven experiments were carried out at different light levels (32–202?Wh?m^?2 at the start of the experiments) in the different experimental years. In one further experiment, the factors light and temperature were crossed, and in one experiment, the factors density of overwintering zooplankton and temperature were crossed. Overall, there was a slight temporal acceleration of the phytoplankton spring bloom, a decline of peak biomass and a decline of mean cell size with warming. The temperature influence on phytoplankton bloom timing, biomass and size structure was qualitatively highly robust across experiments. The dependence of timing, biomass, and size structure on initial conditions was tested by multiple regression analysis of the y-temperature regressions with the candidate independent variables initial light, initial phytoplankton biomass, initial microzooplankton biomass, and initial mesozooplankton (=copepod) biomass. The bloom timing predicted for mean temperatures (5.28°C) depended on light. The peak biomass showed a strong positive dependence on light and a weaker negative dependence on initial copepod density. Mean phytoplankton cell size predicted for the mean temperature responded positively to light and negatively to copepod density. The anticipated mismatch between phytoplankton supply and food demand by newly hatched copepod nauplii occurred only under the combination of low light and warm temperatures. The analysis presented here confirms earlier conclusions about temperature responses that are based on subsets of our experimental series. However, only the comprehensive analysis across all experiments highlights the importance of the factor light.     

Metabolic enzyme activities in shallow- and deep-water chondrichthyans: implications for metabolic and locomotor capacity

Biochemical indices of white (WM) and red muscle (RM) aerobic and anaerobic metabolic capacity were measured in 14 species of benthic and benthopelagic chondrichthyans from a depth of ~90 to 2,200 m to evaluate the relationship between metabolic capacity and depth of occurrence, phylogeny, and locomotor mode. Maximal activities of the enzymes citrate synthase, malate dehydrogenase (MDH), lactate dehydrogenase (LDH), and pyruvate kinase (PK) were analyzed in muscle tissue at 10 °C. These were combined with previously published elasmobranch data in order to represent a comprehensive range of depths, phylogeny, and locomotor modes (i.e., benthic, benthopelagic, pelagic). Significant decreases in WM PK and LDH activities and a lack of significant trends in RM enzyme activities with increasing median depth of occurrence (MDO) indicate a depth-related reduction in both burst-locomotor and metabolic capacity. These trends are consistent with the “visual-interactions hypothesis.” Phylogeny and locomotor mode had little influence on enzyme activities compared to MDO, and the present study suggests similar activities in co-occurring demersal sharks and rays. Overall, the present study indicates low metabolic capacities in deep-sea chondrichthyans, which is important to consider when managing deep-sea fisheries.