Concentrations and fluxes of isoprene and oxygenated VOCs at a French Mediterranean oak forest

The CANOPEE project aims to better understand the biosphere–atmosphere exchanges of biogenic volatile organic compounds (BVOCs) in the case of Mediterranean ecosystems and the impact of in-canopy processes on the atmospheric chemical composition above the canopy. Based on an intensive field campaign, the objective of our work was to determine the chemical composition of the air inside a canopy as well as the net fluxes of reactive species between the canopy and the boundary layer. Measurements were carried out during spring 2012 at the field site of the Oak Observatory of the Observatoire de Haute Provence (O3HP) located in the southeast of France. The site is a forest ecosystem dominated by downy oak, Quercus pubescens Willd., a typical Mediterranean species which features large isoprene emission rates. Mixing ratios of isoprene, its degradation products methylvinylketone (MVK) and methacrolein (MACR) and several other oxygenated VOC (OxVOC) were measured above the canopy using an online proton transfer reaction mass spectrometer (PTR-MS), and fluxes were calculated by the disjunct eddy covariance approach. The O3HP site was found to be a very significant source of isoprene emissions, with daily maximum ambient concentrations ranging between 2–16 ppbv inside and 2–5 ppbv just above the top of the forest canopy. Significant isoprene fluxes were observed only during daytime, following diurnal cycles with midday net emission fluxes from the canopy ranging between 2.0 and 9.7 mg m−2 h1. Net isoprene normalized flux (at 30 °C, 1000 μmol quanta m−2 s−1) was estimated at 7.4 mg m−2 h−1. Evidence of direct emission of methanol was also found exhibiting maximum daytime fluxes ranging between 0.2 and 0.6 mg m−2 h−1, whereas flux values for monoterpenes and others OxVOC such as acetone and acetaldehyde were below the detection limit. The MVK+MACR-to-isoprene ratio provided useful information on the oxidation of isoprene, and is in agreement with recent findings proposing weak production yields of MVK and MACR, in remote forest regions where the NOx concentrations are low. In-canopy chemical oxidation of isoprene was found to be weak and did not seem to have a significant impact on isoprene concentrations and fluxes above the canopy

The Contribution of Social Networks to the Health and Self-Management of Patients with Long-Term Conditions: A Longitudinal Study

Evidence for the effectiveness of patient education programmes in changing individual self-management behaviour is equivocal. More distal elements of personal social relationships and the availability of social capital at the community level may be key to the mobilisation of resources needed for long-term condition self-management to be effective. Aim: To determine how the social networks of people with long-term conditions (diabetes and heart disease) are associated with health-related outcomes and changes in outcomes over time. Methods: Patients with chronic heart disease (CHD) or diabetes (n = 300) randomly selected from the disease registers of 19 GP practices in the North West of England. Data on personal social networks collected using a postal questionnaire, alongside face-to-face interviewing. Follow-up at 12 months via postal questionnaire using a self-report grid for network members identified at baseline. Analysis: Multiple regression analysis of relationships between health status, self-management and health economics outcomes, and characteristics of patients’ social networks. Results: Findings indicated that: (1) social involvement with a wider variety of people and groups supports personal self-management and physical and mental well-being; (2) support work undertaken by personal networks expands in accordance with health needs helping people to cope with their condition; (3) network support substitutes for formal care and can produce substantial saving in traditional health service utilisation costs. Health service costs were significantly (p0.01) reduced for patients receiving greater levels of illness work through their networks. Conclusions: Support for self-management which achieves desirable policy outcomes should be construed less as an individualised set of actions and behaviour and more as a social network phenomenon. This study shows the need for a greater focus on harnessing and sustaining the capacity of networks and the importance of social involvement with community groups and resources for producing a more desirable and cost-effective way of supporting long term illness management

Home Production and Retirement in Couples: A Panel Data Analysis

We analyse the effects of retirement of one partner on home production by both partners in a couple. Using longitudinal data from Germany on couples, we control for fixed household specific effects to address the concern that retirement decisions are correlated with unobserved characteristics that also affect home production. For males and females, we find that own retirement significantly increases the amounts of home production. There are negative cross-effects of retirement on home production done by the partner. The fall in household income at retirement of one of the partners is largely compensated by an increase in total household production

Variability of dimethyl sulphide (DMS), methanethiol and other trace gases in relation with microbial communities from the temperate Atlantic to the Arctic Ocean

Dimethyl sulphide (DMS) plays an important role in the atmosphere by influencing the formation of aerosols and cloud condensation nuclei. In contrast, the role of methanethiol (MeSH) for the budget and flux of reduced sulphur remains poorly understood. In the present study, we quantified DMS and MeSH together with the trace gases carbon monoxide (CO), isoprene, acetone, acetaldehyde and acetonitrile in North Atlantic and Arctic Ocean surface waters, covering a transect from 57.2° N to 80.9° N in high spatial resolution. Whereas isoprene, acetone, acetaldehyde and acetonitrile concentrations decreased northwards, CO, DMS and MeSH retained significant levels at high latitudes, indicating specific sources in polar waters. DMS was the only compound with higher average in polar (31.2 ± 9.3 nM) than in Atlantic waters (13.5 ± 2 nM), presumably due to DMS originating from sea ice. At eight sea-ice stations north of 80° N, in the diatom-dominated marginal ice zone, vertical profiles showed a marked correlation (R2 = 0.93) between DMS and chlorophyll a. Contrary to previous measurements, MeSH and DMS did not co-vary, indicating decoupled processes of production and conversion. The contribution of MeSH to the sulphur budget (represented by DMS+MeSH) was on average 20 % (and up to 50 %) higher than previously observed in the Atlantic and Pacific Oceans, suggesting MeSH as a significant source of sulphur possibly emitted to the atmosphere. The potential importance of MeSH was underlined by several correlations with bacterial taxa, including typical phytoplankton associates from the Rhodobacteraceae and Flavobacteriaceae families. Furthermore, the correlation of isoprene and chlorophyll a with Alcanivorax indicated a specific relationship with isoprene-producing phytoplankton. Overall, the demonstrated latitudinal and vertical patterns contribute to the understanding of central marine trace gases from chemical, atmospheric and biological perspectives

Short-Lived Trace Gases in the Surface Ocean and the Atmosphere

The two-way exchange of trace gases between the ocean and the atmosphere is important for both the chemistry and physics of the atmosphere and the biogeochemistry of the oceans, including the global cycling of elements. Here we review these exchanges and their importance for a range of gases whose lifetimes are generally short compared to the main greenhouse gases and which are, in most cases, more reactive than them. Gases considered include sulphur and related compounds, organohalogens, non-methane hydrocarbons, ozone, ammonia and related compounds, hydrogen and carbon monoxide. Finally, we stress the interactivity of the system, the importance of process understanding for modeling, the need for more extensive field measurements and their better seasonal coverage, the importance of inter-calibration exercises and finally the need to show the importance of air-sea exchanges for global cycling and how the field fits into the broader context of Earth System Science

Non-methane hydrocarbon variability in Athens during wintertime: the role of traffic and heating

Non-methane hydrocarbons (NMHCs) play an important role in atmospheric chemistry, contributing to ozone and secondary organic aerosol formation. They can also serve as tracers for various emission sources such as traffic, solvents, heating and vegetation. The current work presents, for the first time to our knowledge, time-resolved data of NMHCs, from two to six carbon atoms, for a period of 5 months (mid-October 2015 to mid-February 2016) in the greater Athens area (GAA), Greece. The measured NMHC levels are among the highest reported in the literature for the Mediterranean area during winter months, and the majority of the compounds demonstrate a remarkable day-to-day variability. Their levels increase by up to factor of 4 from autumn (October–November) to winter (December–February). Microscale meteorological conditions, especially wind speed in combination with the planetary boundary layer (PBL) height, seem to contribute significantly to the variability of NMHC levels, with an increase of up to a factor of 10 under low wind speed ( &lt; 3&thinsp;m&thinsp;s−1) conditions; this reflects the impact of local sources rather than long-range transport. All NMHCs demonstrated a pronounced bimodal, diurnal pattern with a morning peak followed by a second peak before midnight. The amplitude of both peaks gradually increased towards winter, in comparison to autumn, by a factor of 3 to 6 and closely followed that of carbon monoxide (CO), which indicates a contribution from sources other than traffic, e.g., domestic heating (fuel or wood burning). By comparing the NMHC diurnal variability with that of black carbon (BC), its fractions associated with wood burning (BCwb) and fossil fuel combustion (BCff), and with source profiles we conclude that the morning peak is attributed to traffic while the night peak is mainly attributed to heating. With respect to the night peak, the selected tracers and source profiles clearly indicate a contribution from both traffic and domestic heating (fossil fuel and wood burning). NMHCs slopes versus BCwb are similar when compared with those versus BCff (slight difference for ethylene), which indicates that NMHCs are most likely equally produced by wood and oil fossil fuel burning.</p

Long-Term Care Insurance and Carers' Labor Supply: A Structural Model

In Germany, individuals in need of long-term care receive support through benefits of the long-term care insurance. A central goal of the insurance is to support informal care provided by family members. Care recipients can choose between benefits in kind (formal home care services) and benefits in cash. From a budgetary perspective family care is a cost-saving alternative to formal home care and to stationary nursing care. However, the opportunity costs resulting from reduced labor supply of the carer are often overlooked. We focus on the labor supply decision of family carers and the incentives set by the long-term care insurance. We estimate a structural model of labor supply and the choice of benefits of family carers. We find that benefits in kind have small positive effects on labor supply. Labor supply elasticities of cash benefits are larger and negative. If both types of benefits increase, negative labor supply effects are offset to a large extent

The Effect of Partial Retirement on Labor Supply, Public Balances and the Income Distribution: Evidence from a Structural Analysis

This paper develops a structural dynamic retirement model to investigate effects and corresponding underlying mechanisms of a partial retirement program on labor supply, fiscal balances, and the pension income distribution. The structural approach allows for disentangling the two counteracting mechanisms that drive the employment effects of partial retirement: 1) the crowding-out from full-time employment, and 2) the movement from early retirement or unemployment to partial retirement. It also allows for investigating the role of financial compensations in a partial retirement program. Based on a unique German administrative dataset, I perform counterfactual policy simulations that analyze the role of partial retirement combined with financial subsidies and an increased normal retirement age. The results show that partial retirement extends working lives but reduces the overall employment volume. The fiscal consequences of partial retirement are negative but substantially less so when wages and pensions in partial retirement remain uncompensated. Partial retirement decreases inequality in pension income and provides a way to smooth consumption especially for retirees in lower income deciles in the context of an increased normal retirement age

Heterogeneity in the Relationship between Unemployment and Subjective Well-Being: A Quantile Approach

Unemployment has been robustly shown to strongly decrease subjective well-being (or "happiness"). In the present paper, we use panel quantile regression techniques in order to analyze to what extent the negative impact of unemployment varies along the subjective well-being distribution. In our analysis of British Household Panel Survey data (1996-2008) we find that, over the quantiles of our subjective well-being variable, individuals with high well-being suffer less from becoming unemployed. A similar but stronger effect of unemployment is found for a broad mental well-being variable (GHQ-12). For happy and mentally stable individuals, it seems their higher well-being acts like a safety net when they become unemployed. We explore these findings by examining the heterogeneous unemployment effects over the quantiles of satisfaction with various life domains