Poultry farming is one of the most efficient animal husbandry methods and it provides nutritional security to a significant number of the world population. Using modern intensive farming techniques, global production has reached 133.4 mil. tin 2020, with a steady growth each year. Such intensive growth methods however lead to a significant environmental footprint. Waste materials such as poultry litter and manure can pose a serious threat to environmental and human health, and need to be managed properly. Poultry production and waste by-products are linked to NH3, N2O and CH4 emissions, and have an impact on global greenhouse gas emissions, as well as animal and human health. Litter and manure can contain pesticide residues, microorganisms, pathogens, pharmaceuticals (antibiotics), hormones, metals, macronutrients (at improper ratios) and other pollutants which can lead to air, soil and water contamination as well as formation of antimicrobial/multidrug resistant strains of pathogens. Dust emitted from intensive poultry production operations contains feather and skin fragments, faeces, feed particles, microorganisms and other pollutants, which can adversely impact poultry health as well as the health of farm workers and nearby inhabitants. Fastidious odours are another problem that can have an adverse impact on health and quality of life of workers and surrounding population. This study discusses the current knowledge on the impact of intensive poultry farming on environmental and human health, as well as taking a look at solutions for a sustainable future.

Phthalates are a class of compounds that have found widespread use in industrial applications, in particular in the polymer, cosmetics and pharmaceutical industries. While ingestion, and to a lesser degree inhalation, have been considered as the major exposure routes, especially for higher molecular weight phthalates, dermal exposure is an important route for lower weight phthalates such as diethyl phthalate (DEP). Assessing the dermal permeability of such compounds is of great importance for evaluating the impact and toxicity of such compounds in humans. While human skin is still the best model for studying dermal permeation, availability, cost and ethical concerns may preclude or restrict its use. A range of alternative models has been developed over time to substitute for human skin, especially in the early phases of research. These include ex vivo animal skin, human reconstructed skin and artificial skin models. While the results obtained using such alternative models correlate to a lesser or greater degree with those from in vivo human studies, the use of such models is nevertheless vital in dermal permeation research. This review discusses the alternative skin models that are available, their use in phthalate permeation studies and possible new avenues of phthalate research using skin models that have not been used so far.

An isotope exchange experiment with the short-lived radioactive tracer 13N is used to trace N2O5 uptake into nitrate-containing aqueous aerosol particles. While uptake of 13N-labelled N2O5 to deliquesced Na2SO4 aerosol is consistent with previous studies, efficient exchange of labelled nitrate with the non-labelled nitrate pool was observed in the presence of aerosol-phase nitrate. The experiments provide direct evidence for efficient bulk mass accommodation of N2O5 into aqueous solution with αb > 0.4 at room temperature, as well as for the fast dissociation into nitronium and nitrate. While for experimental reasons this study is limited to non-acidic nitrate-containing aerosol, it is likely that bulk mass accommodation and dissociation are not limiting N2O5 uptake under wider ranges of conditions.

Abstract. An isotope exchange experiment with the short-lived radioactive tracer 13N is used to trace N2O5 uptake into nitrate containing aqueous aerosol particles. While uptake of 13N labelled N2O5 to deliquesced Na2SO4 aerosol is consistent with previous studies, in presence of aerosol phase nitrate efficient exchange of labeled nitrate with the non-labeled nitrate pool was observed. The experiments provide direct evidence for efficient bulk mass accommodation of N2O5 into aqueous solution with an accommodation coefficient >0.4 at room temperature, as well as for the fast disproportionation into nitronium and nitrate. While for experimental reasons this study is limited to non-acidic aerosol, it is likely that mass accommodation is not limiting N2O5 uptake also under wider ranges of conditions.

The heterogeneous loss of dinitrogen pentoxide (N2O5) to aerosol particles has a significant impact on the night-time nitrogen oxide cycle and therefore the oxidative capacity in the troposphere. Using a 13N short-lived radioactive tracer method, we studied the uptake kinetics of N2O5 on citric acid aerosol particles as a function of relative humidity (RH). The results show that citric acid exhibits lower reactivity than similar dicarboxylic and polycarboxylic acids, with uptake coefficients between ∼ 3 × 10-4–∼ 3 × 10-3 depending on humidity (17–70 % RH). At RH above 50 %, the magnitude and the humidity dependence can be best explained by the viscosity of citric acid as compared to aqueous solutions of simpler organic and inorganic solutes and the variation of viscosity with RH and, hence, diffusivity in the organic matrix. Since the diffusion rates of N2O5 in highly concentrated citric acid solutions are not well established, we present four different parameterizations of N2O5 diffusivity based on the available literature data or estimates for viscosity and diffusivity of H2O. Above 50 % RH, uptake is consistent with the reacto-diffusive kinetic regime whereas below 50 % RH, the uptake coefficient is higher than expected from hydrolysis of N2O5 within the bulk of the particles, and the uptake kinetics is most likely limited by loss on the surface only. This study demonstrates the impact of viscosity in highly oxidized and highly functionalized secondary organic aerosol material on the heterogeneous chemistry of N2O5 and may explain some of the unexpectedly low loss rates to aerosol derived from field studies.

Dinitrogen pentoxide has aroused significant interest in atmospheric chemistry because of its importance in the night time chemistry of nitrogen oxides to influence the tropospheric oxidation capacity. We have used an established method of N-13 production to synthesize N-13 labeled N2O5 for the first time in order to study N2O5 uptake kinetics on aerosol particles. N-13 is produced via the 16 O(p, alpha) N-13 reaction in a gas target attached to the IP2 endstation of the Injector 2 cyclotron at PSI. The (NO)-N-13 produced in the gas target is transported to a laboratory where it is mixed, under dry conditions, with non-labeled NO and O 3 in a gas reactor, giving (NNO5)-N-13. The N2O5 thus produced is fed into an aerosol flow tube together with a humidified aerosol gas flow. The gaseous species present in the resulting gas flow are selectively separated via a narrow parallel plate diffusion denuder system, while aerosol particles can be trapped on a particle filter placed at the end of the denuder system. The activity of the N-13 labeled species trapped on the denuder plates and in the particle filter can be monitored via scintillation counters. A system for the routine online production of N-13 labeled N2O5 has been assembled and used to assess the conformity of the results by kinetic modeling of gas phase N2O5 chemistry, showing good agreement. A few exemplary experiments of uptake of labelled N2O5 to ammonium sulfate and citric acid particles are presented that are in good agreement with results obtained with other methods reported in the literature.

Atmospheric soluble organic aerosol material can become solid or semi-solid. Due to increasing viscosity and decreasing diffusivity, this can impact important processes such as gas uptake and reactivity within aerosols containing such substances. This work explores the dependence of shikimic acid ozonolysis on humidity and thereby viscosity. Shikimic acid, a proxy for oxygenated reactive organic material, reacts with O-3 in a Criegee-type reaction. We used an environmental microreactor embedded in a scanning transmission X-ray microscope (STXM) to probe this oxidation process. This technique facilitates in situ measurements with single micron-sized particles and allows to obtain near-edge X-ray absorption fine structure (NEXAFS) spectra with high spatial resolution. Thus, the chemical evolution of the interior of the particles can be followed under reaction conditions. The experiments show that the overall degradation rate of shikimic acid is depending on the relative humidity in a way that is controlled by the decreasing diffusivity of ozone with decreasing humidity. This decreasing diffusivity is most likely linked to the increasing viscosity of the shikimic acid-water mixture. The degradation rate was also depending on particle size, most congruent with a reacto-diffusion limited kinetic case where the reaction progresses only in a shallow layer within the bulk. No gradient in the shikimic acid concentration was observed within the bulk material at any humidity indicating that the diffusivity of shikimic acid is still high enough to allow its equilibration throughout the particles on the timescale of hours at higher humidity and that the thickness of the oxidized layer under dry conditions, where the particles are solid, is beyond the resolution of STXM.

Cooking emissions are a major contributor to indoor and outdoor PM2.5 organic aerosols (Mohr et al., 2012). Understanding the changes in behaviour and properties of these emissions with atmospheric processing is crucial to quantify their effects on climate and to design effective abatement strategies. Nevertheless, very little is known about the microstructural properties and the effects of atmospheric processing thereon, properties undoubtedly related with the optical and hygroscopic properties determinant on assessing the effects of aerosols on climate change. The present study aimed at the characterization of the chemical heterogeneities and changes in the internal microstructure of individual aerosol particles from different cooking activities. The major goal was to establish a relation between changes in the carbon functional groups and photochemical aging in laboratory generated aerosol particles, not only identifying the different groups but the spatial distribution within the individual particle structure. The aging experiments were conducted in the PSI mobile smog chamber (Platt et al., 2012) with grilled chicken/NOx/hν and boiled vegetables/NOx/hν, as testing systems for the cooking emissions. Two different samples were collected during the experiment timeline, from primary and aged emissions, to be subsequently analyzed by STXM/NEXAFS at the PolLux beamline of the PSI SLS (Raabe et al., 2008). Complementary highresolution SEM analyses were conducted to complete the microstructural study. Results corroborated that cooking activities emit a variety of organic compounds that behave very differently during atmospheric processing from source to source and type of activity. This is also evidenced by changes in the particle structure. Vegetable boiling produced a wide range of primary organic structures not present when the emission is highly aged. These differences stressed the complexity in the interpretation of the results. In addition, no typical aged features were found on the NEXAFS spectra of the particles. In the case of the grilled meat, a major contribution of unsaturated moieties was found in particles from the slightly aged samples. The unsaturated groups seem to be the nuclei of the later condensed groups forming coatings of different thicknesses (Fig. 1). This was consistent with the results from the AMS analysis. This novel information is especially interesting for the improvement of the radiative transfer and CCN (Cloud Condensation Nuclei) activity estimations that include a core-to-shell particle model in climate change studies.

Micro synchrotron radiation X‐ray fluorescence (μ‐SRXRF) is a powerful spectroscopy technique that uses synchrotron radiation to induce X‐ray fluorescence in samples and provides exhaustive information on the micron and submicron scale. Among the major advantages of μ‐SRXRF spectroscopy are its nondestructive nature and that samples can usually be analyzed without pretreatment. At the ESRF (Grenoble, France) ID‐21 beamline, we examined PM10 samples collected at two sites in the Province of Trieste, Italy, in order to determine possible correlations among some low‐ to mid‐Z elements (S, Cl, K, Ca, Ti, V, Cr, Mn, and Fe), as well as investigated the possibility of using synchrotron radiation imaging techniques as a way to examine the granulometry of PM10 particles containing the various chemical elements. A consistent significant correlation between Ca and S has been found, which, coupled with the data obtained in a related study, indicates that a major part of the sulfate is present as CaSO4. Granulometry measurement via imaging techniques has shown that some elements such as Fe, Ca, and S are more amenable to this type of analysis than others. Additionally, the spatial homogeneity of a PM2.5 certified reference material (NIST SRM‐2783) has been investigated by analyzing four adjacent areas on the certified sample (total area 1 mm2). The certified reference material has shown a percentage relative standard deviation less than 7% for Al, Si, P, S, Cl, K, Ca, V, Cr, and Fe, and close to 17% for Ti and Mn. Copyright © 2011 John Wiley & Sons, Ltd.