Conventional PVC Research Articles

Assessing the environmental impacts of reclaimed and conventional water in hydroponics based on a life cycle assessment approach

ABSTRACT As the global population is approaching toward 9 billion by 2050, challenges of food and water scarcity intensify. Hydroponics, an innovative and eco-friendly technology, has gained prominence in addressing these challenges. This study employs life cycle assessment (LCA) to comprehensively evaluate the environmental and economic impacts of utilizing reclaimed water in a hydroponic system. Results from midpoint, endpoint, and normalized analyses reveal key contributors to the hydroponic system's environmental burden, including water, substrates, fertilizers, and energy sources. Significant impacts have been observed in marine and terrestrial ecotoxicity as well as photochemical ozone formation. Reclaimed water consistently demonstrates lower environmental impacts compared to conventional water across various indicators, such as climate change (131 kg CO2 eq.), fine particulate matter formation (0.108 kg PM2.5 eq.), and freshwater consumption (0.291 m3). The study emphasizes the potential of hydroponics with reclaimed water to offer sustainable and environmentally friendly agricultural practices. The detailed LCA results provide valuable insights for policymakers and stakeholders, promoting the adoption of hydroponics to address food and water scarcity challenges. From the findings, reclaimed water in hydroponics lowers the environmental impacts as compared to conventional water and PVC along with electricity is the major contributor in environmental burden.

Modelling and performance investigation of a solar chimney power plant with glass-covered solar collector

ABSTRACT Solar chimney power plants (SCPP) exploit solar radiation to create an up-draft airflow to run a turbine. This article proposes an innovative design of an SCPP that consists of transparent glass covered solar collector. Outdoor experiments have been carried out in the arid climates of Tikrit city, Iraq, with galvanized metal tower installed instead of conventional PVC solar towers. Performance of the SCPP has been studied with and without transparent cover for collector periphery heights of 2 and 4 cm. Measurements of ambient temperature, chimney inlet temperature, interior and outlet air temperatures, humidity, air mass flow rate, and solar irradiance values were recorded from 9:00 am to 4:00 pm throughout the month of May 2021. Results show that the solar chimney collector with a periphery height of 2 cm performed better than that with the 4-cm periphery height. In addition, using transparent cover in SCPP increases the air outlet temperature by 16.4°C and air flowrate augments by around 34%. Thermal efficiency of the solar chimney with non-covered tower is found to be 10.3% whereas for a glass covered tower it increases to 14.6%, which is a remarkable 41% enhancement. Likewise, mechanical and electrical power output augment by 39.6% and 40.3% using transparent cover in SCPP. Such innovation in SCPP design is proven apposite for hot arid climates.

Ease of endotracheal intubation with the conventional polyvinyl chloride endotracheal tube versus wire-reinforced flexometallic tube through the intubating laryngeal mask airway: A comparative study.

The aim of our study was to compare the ease of intubation when using conventional PVC tubes versus the wire-reinforced flexometallic tubes with the ILMA-FastrachTM. The number of attempts, time taken and additional maneuvers were noted. Intra-operative hemodynamic changes, post-operative sore throat, bleeding and hoarseness of voice was recorded over a period of 24 hours. After informed consent, 60 ASA I-II patients undergoing elective surgeries under general anesthesia were allocated to undergo blind intubation with the PVC tube or the wire-reinforced flexometallic tube. More attempts were required for successful intubation using the wire-reinforced tube than the PVC tube with 76.7% passing in the first attempt in the PVC, and 53.3% passing in the first attempt in the flexometallic group. (P = 0.4). Average time for intubation in the PVC group: 28.24 ± 7.22 seconds. Average time for intubation in the flexometallic tube: 45.8 ± 15.78 sec. Occurrence of post-operative sore throat was 13.3% in the PVC group and 26.6% in the flexometallic group, with minimal hoarseness of voice 3.3% in the PVC group and 10% in the flexometallic group. There was also a slightly higher hemodynamic response in those who were intubated with the flexometallic tube than a PVC tube. Intubating via the ILMA-Fastrach with the PVC tube offered better intubating conditions with regards to lesser time taken, lesser attempts, less manipulation, and less hemodynamic variations as compared to the patients who were intubated using the wire-reinforced tube.

Synthesis internal-plasticized PVC copolymer resin from industrial application view: Copolymerization of vinyl chloride with poly(ethylene glycol) monomethyl ether methacrylate via suspension polymerization

Developing internal-plasticized poly(vinyl chloride) (PVC) resin has been recognized as an effective way to deal with the issues of conventional PVC products such as toxicity and deterioration in properties caused by the migration of plasticizer. Herein, the copolymerization of vinyl chloride with commercial available poly(ethylene glycol) monomethyl ether methacrylate (PEGMA) is firstly conducted via suspension polymerization and internally plasticized random copolymers (PVEGA) are synthesized successfully. These PVEGA copolymers were intensively characterized by FTIR, 1H NMR, GPC, DSC, DMTA, and SEM to determine the composition, number-average molecular weight (Mn), dispersity, glass transition temperature (Tg), and the micromorphology. As a result, the high transparency and the fracture images demonstrated the good compatability between PVC chains with long-chain polyether. The Tg of PVEGA decreased gradually from 80 to 0 °C with the fraction of PEGMA in the copolymer increased from 7 to 37 %. Furthermore, the PVEGA copolymer exhibits outstanding processibility and mechanical performance. Under optimal composition, the tensile strength and the elongation at break can reach to 8 MPa and 525 %, respectively. Meanwhile, the PVEGA copolymers exhibit much lower migration either in water or in orgnic solvent and excellent performance in hemolysis and cytotoxicity, showing great application potential in medical devices.

Ionophore-Based Polymeric Sensors for Potentiometric Assay of the Anticancer Drug Gemcitabine in Pharmaceutical Formulation: A Comparative Study.

Gemcitabine is a chemotherapeutic agent used to treat various malignancies, including breast and bladder cancer. In the current study, three innovative selective gemcitabine hydrochloride sensors are developed using 4-tert-butylcalix-[8]-arene (sensor 1), β-cyclodextrin (sensor 2), and γ-cyclodextrin (sensor 3) as ionophores. The three sensors were prepared by incorporating the ionophores with o-nitrophenyl octyl ether as plasticizer and potassium tetrakis(4-chlorophenyl) borate as ionic additive into a polyvinyl chloride polymer matrix. These sensors are considered environmentally friendly systems in the analytical research. The linear responses of gemcitabine hydrochloride were in the concentration range of 6.0 × 10-6 to 1.0 × 10-2 mol L-1 and 9.0 × 10-6 to 1.0 × 10-2 mol L-1 and 8.0 × 10-6 to 1.0 × 10-2 mol L-1 for sensors 1, 2, and 3, respectively. Over the pH range of 6-9, fast-Nernst slopes of 52 ± 0.6, 56 ± 0.3, and 55 ± 0.8 mV/decade were found in the same order with correlation regressions of 0.998, 0.999, and 0.998, respectively. The lower limits of detection for the prepared sensors were 2.5 × 10-6, 2.2 × 10-6, and 2.7 × 10-6 mol L-1. The sensors showed high selectivity and sensitivity for gemcitabine. Validation of the sensors was carried out in accordance with the requirements established by the IUPAC, while being inexpensive and easy to use in drug formulation. A statistical analysis of the methods in comparison with the official method showed that there was no significant difference in accuracy or precision between them. It was shown that the new sensors could selectively and accurately find gemcitabine hydrochloride in bulk powder, pharmaceutical formulations, and quality control tests. The ionophore-based sensor shows several advantages over conventional PVC membrane sensor sensors regrading the lower limit of detection, and higher selectivity towards the target ion.

Fungal Diversity and Dynamics during Long-Term Immersion of Conventional and Biodegradable Plastics in the Marine Environment

Plastics are associated with a worldwide pollution crisis, with strong negative impacts on both terrestrial and aquatic ecosystems. In marine environments, various organisms are colonizing plastic debris, but few studies have focused on fungal communities despite their non-trivial ecological roles in the marine environment. In this study, different types of plastics (biodegradable and conventional) immersed in marine natural environments and under laboratory controlled settings were collected after long-term colonization. Using a metabarcoding approach targeting two genetic markers, namely, the ITS2 region and the V4 hypervariable region of the 18S rRNA gene, we highlighted that fungal communities associated with plastic polymers were distinct from those found in the surrounding seawater. They also differed significantly between sampling locations and the nature of immersed polymers, indicating that fungal colonization was impacted by the sites and types of plastics, with clear dissimilarities between conventional and biodegradable polymers. Specifically for the conventional PVC polymer (Polyvinyl chloride), we also observed the successive stages of biofilm development and maturation after long-term immersion in seawater. A noticeable change in the fungal communities was observed around 30–40 days in natural settings, suggesting a colonization dynamic likely associated with a transition from biofilm formation to distinct communities likely associated with biofouling. Overall, this study strengthens the idea that the fungal kingdom is an integrated part of the “plastisphere”.

Study on the Physical, Thermal and Mechanical Properties of SEBS/PP (Styrene-Ethylene-Butylene-Styrene/Polypropylene) Blend as a Medical Fluid Bag

The presence of DEHP in PVC-based medical bags poses a significant health risk to patients undergoing blood transfusion. In order to fabricate safer medical fluid bag materials, the use of SEBS/PP polymer blend as a potential material was investigated. Polymeric blends with varying weight percentages of styrene-ethylene-butylene-styrene/polypropylene (SEBS/PP) were fabricated by melt mixing using an internal Haake mixer. The physical properties of the SEBS/PP polymer blends were investigated using differential scanning calorimetry (DSC), X-ray diffraction (XRD), and inductively coupled plasma–mass spectrometry (ICP-MS). In addition, measurements of the mechanical strength (tensile strength and Young’s modulus) as per ASTM 638, polymer hardness was tested using a durometer and swelling was analysed through water absorption and compared with commercial PVC-based blood bags. The results indicate that the SEBS/PP 50/50 blend has approximately similar characteristics as PVC-based blood bags. The SEBS/PP polymer blend possesses approximate tensile strength and Young’s modulus with values of 23.28 MPa and 14.42 MPa, respectively, to that of the conventional PVC blood bags. The results show that the SEBS/PP polymer blends have negligible zinc and aluminium migration with values of 1.6 and 2.1 mg/kg, respectively, and do not elute any harmful leachates, while the thermal studies indicate that the studied SEBS/PP materials are capable of withstanding steam sterilisation at 120 °C and cold storage below −40 °C. The investigated material can be utilized for medical fluid bags and contributes towards sustainable development goals, such as SDG 3 to ensure healthy lives and promote well-being, as well as SDG 12 to ensure sustainable consumption and production patterns.

A comparison of oil and grease removal from automobile workshop stormwater runoff using gravel, granular activated carbon, rice husk and conventional oil and grease (O&G) trap

Oil and grease (O&G) removal efficiencies using 4 automobile stormwater treatment systems were investigated and compared. The treatment systems used were: low-cost granular activated carbon–rice husk (GAC–RH) filter system, river gravel–granular activated carbon (GR–GAC) filter system, rice husk only (RH) filter system and the conventional PVC O&G trap (COT). Sampling of automobile stormwater from the five selected automobile workshops was carried out using the manual grab sampling methods. The treatment involved filtration using the low-cost technologies and O&G separation from stormwater. GAC–RH exhibited the highest O&G removal with an average removal efficiency of 43.2% from all the automobile workshops, followed by RH with an average removal efficiency of 31%. O&G removal using GR–GAC and COT resulted in average removal efficiencies of 28.6% and 26.8%, respectively. Further studies need to be carried out to optimize the GAC and RH low-cost filter materials for the purpose of achieving the USEPA and Nigerian effluent standards of 0.1 mg/L, since all the treatment systems produced effluents with minimum concentrations ranging between 0.8 mg/L and 3.6 mg/L.

Edible Film Coatings to Extend the Shelf-Life of Fresh-Cut Pineapple

This study proposes an innovative coating material and procedure to extend the shelf-life of fresh-cut pineapple classified as “minimally processed foods”. The novelty of this work consists of the using of biodegradable cases for the storage of fruits during the experiments under refrigerated conditions. In addition, the application of the coating process was evaluated over a period of 15 days and a complete characterization of the Volatile Organic Compounds (VOCs) was performed by gaschromatography coupled to mass spectrometry (GC-MS) to assess the effect of the coating material on the flavor, the appearance and the quality of the fruits. Results demonstrated that the application of carboxymethyl cellulose and ascorbic acid on pretreated fresh-cut pineapple is able to reduce the aging process and prolonge the shelf-life of pineapple without requiring conventional PVC cases for storage.

Lipophilic Fluorescent Dye Liquids: Förster Resonance Energy Transfer-Based Fluorescence Amplification for Ion Selective Optical Sensors Based on a Solvent Polymeric Membrane.

Optical sensors based on solvent polymeric membranes have the potential to measure analytes present in an aqueous solution through the development of a tailored method for a specific target. However, limits in the concentrations of the component dyes have prevented improvements in sensitivity. We propose a Förster resonance energy transfer (FRET)-based fluorescence amplification system for ion-selective optical sensors using a highly fluorescent liquid material composed of a lipophilic phosphonium cation and a pyrene modifying sulfonate anion ([P66614][HP-SO3]), as both the plasticizer and donor, in addition to a combination of the lipophilic phosphonium cation and the fluorescein dodecyl ester anion ([P66614][12-FL]) as the fluorescent sensing dye acceptor. For ion extraction-based sensing, the donor and acceptor were retained in the plasticized PVC membrane with negligible leaching upon exposure to acidic and basic aqueous solutions. Systematic investigation of the donor and acceptor ratios clarified the effect of the amplification factor and the sensitivity of the sensor. At an acceptor doping level of 0.5 mol % (vs donor), an approximately 22-fold higher sensitivity was obtained compared to that of a conventional PVC membrane optical sensor. During ion measurement based on the coextraction of protons and anions, selectivity following the Hofmeister order was observed, which was controlled by the addition of ionophores. The proposed FRET system based on a lipophilic fluorescent liquid material has the potential to significantly improve the sensitivities of optical sensors using solvent polymeric membranes with high selectivities for various target analytes.

Ionic Liquid-Based Dye for Highly Sensitive Optical Sensing Based on FRET and Ion Extraction System Using Plasticized PVC Membrane

Ionic Liquid-Based Dye for Highly Sensitive Optical Sensing Based on FRET and Ion Extraction System Using Plasticized PVC Membrane

Comparison of conventional with Parker flex-tip tracheal tube for intubation through air-Q intubating laryngeal airway

Background and Aims:The problem of difficult and failed intubation led to increased development of equipment for airway management. A number of supraglottic airways have now been developed to facilitate the passage of tracheal tubes. Conventional PVC tracheal tubes are recommended for intubation through the air-Q ILA. No study has compared different PVC tubes for blind intubation through air-Q ILA. Thus, we undertook this prospective, randomised, single blind study to compare two PVC tracheal tubes with different designs viz. conventional PVC tracheal tube (TT) and Parker flex-tip TT with regards to success rate, ease of intubation and total time required for successful intubation through air-Q ILA.Material and Methods:One hundred patients of either sex, aged 18–60 years, belonging to American Society of Anesthesiologists (ASA) physical status class I and II scheduled for elective surgery under general anesthesia requiring endotracheal intubation were included in the study. Blind intubation using conventional PVC TT and Parker flex-tip tube was done in group A (n = 50) and group B (n = 50), respectively.Results:The first attempt success rate in Parker flex-tip TT was significantly more as compared to conventional PVC TT (P = 0.002). Success rate of intubation was significantly more in Parker flex-tip TT as compared to conventional PVC TT (P = 0.004). The intubation was significantly easy in Parker flex-tip tube as compared to conventional PVC TT (P = 0.002). Total time of intubation was less in Parker flex-tip tube as compared to PVC TT (P = 0.043).Conclusion:Unique design of the Parker Flex-tip TT resulted in increase in success rate, first attempt success rate and ease of intubation in group B in present study.

Poly(vinyl chloride) reinforced Schiff base as an eco-friendly alternative to conventional PVC

A new Schiff base (L) was synthesized and confirmed by 1HNMR, FTIR spectroscopy. The modified PVC with new Schiff base (L) was synthesized to produce a homogenous blend (PVC-L). A homogenous blend (PVC-L) added to copper chloride to produce PVC-L-Cu(II). The PVC films had been irradiated with an ultraviolet light for long period and confirmed by FTIR spectroscopy, weight loss and surface morphology was investigated by scanning electron microscopy.

Enhancing the biocompatibility of Sodium Membrane Electrodes by Using Chitosan-CuO and Chitosan-CuO-Heparin Composite Membranes

We investigate the effect of introducing chitosan CuO-nanoparticle and heparin loading chitosan CuO nanoparticle composite membranes to PVC based sodium selective membrane electrode to enhance its biocompatibility and reduce its highly thrombogenicity. The potentiometric responses of three sets of electrodes were studied: (1) conventional PVC membrane electrode, (2) conventional PVC membrane electrode sandwiched with chitosan-CuO membrane (CH-CuO-PVC), and (3) conventional PVC membrane electrode sandwiched with chitosan-CuO-heparin membrane (CH-CuO-H-PVC). Potentiometric response characteristics of the CH-CuO-PVC and CH-CuO-H-PVC membrane electrodes (e.g., detection limit, linear range, response slope, and selectivity coefficients) were found to be comparable to that of the conventional PVC-based sodium electrodes. Biocompatibility was assessed for all membranes (PVC and CH-CuO-PVC and CH-CuO-H-PVC) through platelet adhesion protocol. SEM and platelet counts have shown that CH-CuO and CH-CuO-H have improved biocompatibility compared to the classical PVC membranes.

Laboratory evaluation of a new device for water drainage in roadside slope along railway systems

The majority of the existing railway systems in China, from roadside slopes to retaining walls, suffered from poor drainage induced failures. Recently, a new drainage device was proposed to tackle these problems. Preliminary field implementations indicated that the new drainage device could effectively remove groundwater from the surrounding soil without any clogging effect. However, at present, most existing designs are purely based upon the engineers' personal experience and judgement; there is no well-established design method to take full advantage of the device.In this study, a series of laboratory modeling tests were conducted to investigate flow rates, and the optimum installation angle of the drainage device. After that, the long-term performance of the drainage device and conventional perforated PVC pipe under multiple wetting-drying cycles was also evaluated and compared. The results indicate that during the constant head tests, the flow rates in the new drainage device initially increased with an increase in the installation angles of the drainage device from 0° to 15°, and then decreased from 15° to 60°. An inclination angle from 5° to 15° is recommended for this new drainage device when installed in the exiting railway cut slope. The clogging effect was not a primary concern for the applications of this new device. The proposed drainage device provides an alternative way to tackle the poor drainage problem in the exiting railway cut slopes and retaining walls.

Ionic liquid-based dye: A “Dyed plasticizer” for rapid and highly sensitive anion optodes based on a plasticized PVC membrane

Abstract An ionic liquid-based dye was synthesized and directly used as a plasticizer in a plasticized poly(vinyl chloride) (PVC) membrane-based anion optode. In contrast to conventional PVC-based optode membranes, the optode membrane presented can contain a very high concentration (∼296.1 mmol/kg) of dye molecules (for conventional membranes, the concentration is typically 5–50 mmol/kg), which allowed the preparation of a very thin membrane (∼0.8 μm) exhibiting a rapid response time (6.5 s), with sufficient sensitivity (1.2 Absorbance unit (AU)) and excellent response reversibility. We prepared the ionic liquid-based dye using trihexyltetradecylphosphonium (P66614) as a lipophilic monocation and naphtholphthalein (NP) as a dianion. The prepared ionic liquid-based dye contained approximately 40% dye relative to the formula [P66614]2[NP], as confirmed by proton NMR measurements and elemental analysis. Optimized PVC content of the plasticized PVC membrane, without leaching of dye, was 10 wt%. Under these conditions, surprisingly, the membrane exhibited fully reversible responses to acidic and basic solutions, even though the dye was not lipophilized using long alkyl chains, something that has been considered an indispensable chemical modification for dyes used in typical ion-selective optodes. A comparison with conventional plasticized PVC membranes, using nitrophenyl octyl ether (NPOE) as a typical plasticizer and a lipophilic derivative of NP as a lipophilic dye, was carried out in terms of the response time and sensitivity, the results of which demonstrated the advantages of the present approach. Finally, as the simplest application, a plasticized PVC membrane based on an ionic liquid-based dye was successfully applied to coextraction-based anion sensing.

Shelf life extension of white mushrooms (Agaricus bisporus) by low temperatures conditioning, modified atmosphere, and nanocomposite packaging material

Abstract In this work, we have explored a new integrated approach for the shelf life extension of button mushrooms ( Agaricus bisporus ). The effect of temperature (4 °C and 25 °C), packaging configuration (PET/coating/LLDPE oxygen barrier material over conventional PVC stretchable film), and modified atmosphere (15% O 2 /5% CO 2 /80% N 2 over air) were monitored during 10 days of storage. The influence of a chitosan coating deposited on the cap surface was also investigated. Temperature was the most important factor in preserving the quality attributes of mushrooms over time. The test material had a positive impact on weight loss, cap opening percentage, and firmness of mushrooms compared with the control film (∼1.0% versus ∼7.1%; ∼55% versus ∼65%; and ∼10.3 N versus ∼7.6 N, respectively), which was ascribed to the excellent and good oxygen and water vapor barrier properties of the new material, respectively. Mushrooms packaged under the modified atmosphere behaved decidedly better after a prolonged storage time of 22 days at 4 °C. Impressively, after this extended temporal window, the mushrooms looked freshly packed by fully recovering their original color. We explained this striking observation in consideration of the oxygen that permeated the package during these additional 12 days of storage, which would have promoted a gradual resumption of respiratory activity in the overall metabolism of the mushrooms after the “freezing” effect of the rich-CO 2 atmosphere inside the package.

Structurally Enhanced Self-Plasticization of Poly(vinyl chloride) via Click Grafting of Hyperbranched Polyglycerol.

A highly self-plasticized poly(vinyl chloride) (PVC) is demonstrated for the first time via click grafting of hyperbranched polyglycerol (HPG). The plasticizing effect of the grafted HPG on PVC is systematically investigated by various analytical methods. The amorphous and bulky dendritic structure of HPG efficiently increases the free volume of the grafted PVC, which leads to a remarkably lower glass transition temperature comparable to that of the conventional plasticized PVC. Viscoelastic analysis reveals that HPG considerably improves the softness of the grafted PVC at room temperature and promotes the segmental motion in the system. The HPG-grafted PVC films exhibit an exceptional stretchability unlike the mixture of PVC and HPG because the covalent attachment of HPG to PVC allows it to maintain its homogeneous and well-organized architecture under tensile stretching. The work provides valuable insights into the design of highly flexible and stretchable polymeric materials by means of introducing hyperbranched side chains.

Comparison of success rate of intubation through Air-Q with ILMA using two different endotracheal tubes.

Background and Aims:Air-Q™ is a newly introduced airway device, which can be used to facilitate endotracheal intubation. The primary aim of this study was to assess whether use of two different endotracheal tubes (ETTs) (standard polyvinyl chloride [PVC] and reinforced PVC) increases the success rate of blind intubation through Air-Q™ (Group Q) when compared with intubating laryngeal mask airway (ILMA- Fastrach™) keeping ILMA as control (Group I).Methods:One hundred and twenty patients aged between 18 and 60 years with American Society of Anesthesiologists physical status I-II, undergoing elective surgery under general anaesthesia, were enrolled into this prospective, randomised, case–control study to compare the success rate of tracheal intubation between ILMA (Fastrach™) and Air-Q™ intubating laryngeal airway. Those patients with anticipated difficult airway were excluded from the study. All the recruited patients completed the study. Reinforced PVC ETT was used in both airway devices to secure intubation. Since standard PVC tube is recommended for use in Air-Q, when first intubation attempt failed, second or third attempt was made with standard PVC ETT. Total of three attempts were made for each procedure: Whereas in ILMA group, only reinforced tube was used in all three attempts.Results:The overall success rate after three attempts was more with Air-Q (96.6%) in our study compared with ILMA (91.6%) but no significant difference was seen between the groups (P = 0.43).Conclusion:The present study shows that when intubation with reinforced tube fails, the success rate with use of conventional PVC tube is more with Air-Q when compared with ILMA.

Photodegradation effects on CO2 emissions from litter and SOM and photo-facilitation of microbial decomposition in a California grassland

Decomposition of soil organic matter (SOM) and plant litter has been shown to be affected by high solar radiation; this could partly explain why biogeochemical models underestimate decomposition in arid and semi-arid ecosystems. We set out to test the effect of using traditional PVC chambers for measuring soil gas fluxes versus quartz chambers that allowed passage of light during field measurements in a dry-land field in Davis, CA. Results showed that fluxes from quartz-top chambers were on average 29% higher than from opaque chambers. We also studied the effect of solar light exposure on decomposition of native grass litter and SOM in a field experiment where plots were shaded or left exposed for 157 days during summer; litter did not seem to be affected by exposure to light. However, we concluded that SOM decomposition was affected by light exposure since shaded soil had similar respiration to sunlight-exposed soil indicating that microbial respiration occurred under the shade while photo-degradation likely occurred under the sun. Additionally, 15N-labeled grass was placed in litter bags in the field with either clear filters to allow light or aluminum covers to block light; 3-month exposure caused a change in lignin degradability as indicated by the change in the Ad/Al ratio. Incubation of that litter showed 9.3% more CO2 produced from litter in clear and aluminum bags than unexposed litter. This showed that photo-facilitation occurred although to a small degree and was a result of light exposure and/or heat degradation. We attributed the similar respiration from clear- and aluminum-exposed litter to heat degradation of the aluminum-exposed litter. In conclusion, our results show that in hot dry ecosystems conventional PVC chambers underestimate measured CO2 flux rates; sunlight exposure changes litter chemistry and appears to affect the degradation of soil organic matter, but the magnitude of degradation depends on an interaction of factors such as soil temperature and moisture.