scholarly journals Use of a heated graphite scrubber as a means of reducing interferences in UV-absorbance measurements of atmospheric ozone

2017 ◽  
Vol 10 (6) ◽  
pp. 2253-2269 ◽  
Author(s):  
Andrew A. Turnipseed ◽  
Peter C. Andersen ◽  
Craig J. Williford ◽  
Christine A. Ennis ◽  
John W. Birks
Keyword(s):  
Water Vapor ◽  
Solid Phase ◽  
Mercury Vapor ◽  
Packed Bed ◽  
The United States ◽  
Voc Adsorption ◽  
Clean Air ◽  
Smog Chambers ◽  
Equivalent Method ◽  
Ambient Measurements

Abstract. A new solid-phase scrubber for use in conventional ozone (O3) photometers was investigated as a means of reducing interferences from other UV-absorbing species and water vapor. It was found that when heated to 100–130 °C, a tubular graphite scrubber efficiently removed up to 500 ppb ozone and ozone monitors using the heated graphite scrubber were found to be less susceptible to interferences from water vapor, mercury vapor, and aromatic volatile organic compounds (VOCs) compared to conventional metal oxide scrubbers. Ambient measurements from a graphite scrubber-equipped photometer and a co-located Federal equivalent method (FEM) ozone analyzer showed excellent agreement over 38 days of measurements and indicated no loss in the scrubber's ability to remove ozone when operated at 130 °C. The use of a heated graphite scrubber was found to reduce the interference from mercury vapor to ≤ 3 % of that obtained using a packed-bed Hopcalite scrubber. For a series of substituted aromatic compounds (ranging in volatility and absorption cross section at 253.7 nm), the graphite scrubber was observed to consistently exhibit reduced levels of interference, typically by factors of 2.5 to 20 less than with Hopcalite. Conventional solid-phase scrubbers also exhibited complex VOC adsorption and desorption characteristics that were dependent upon the relative humidity (RH), volatility of the VOC, and the available surface area of the scrubber. This complex behavior involving humidity is avoided by use of a heated graphite scrubber. These results suggest that heated graphite scrubbers could be substituted in most ozone photometers as a means of reducing interferences from other UV-absorbing species found in the atmosphere. This could be particularly important in ozone monitoring for compliance with the United States (U.S.) Clean Air Act or for use in VOC-rich environments such as in smog chambers and monitoring indoor air quality.

scholarly journals Use of a Heated Graphite Scrubber as a Means of Reducing Interferences in UV-Absorbance Measurements of Atmospheric Ozone

2017 ◽  
Author(s):  
Andrew A. Turnipseed ◽  
Peter C. Andersen ◽  
Craig J. Williford ◽  
Christine A. Ennis ◽  
John W. Birks
Keyword(s):  
Water Vapor ◽  
Solid Phase ◽  
Mercury Vapor ◽  
Packed Bed ◽  
Voc Adsorption ◽  
Volatile Organic ◽  
Clean Air ◽  
Volatile Organic Hydrocarbons ◽  
Equivalent Method ◽  
Ambient Measurements

Abstract. A new solid-phase scrubber for use in conventional ozone photometers was investigated as a means of reducing interferences from other UV-absorbing species and water vapor. It was found that when heated to 100–130 °C, a tubular graphite scrubber efficiently removed up to 500 ppb ozone and ozone monitors using the heated graphite scrubber were found to be less susceptible to interferences from water vapor, mercury vapor, and aromatic volatile organic hydrocarbons (VOCs) compared to conventional metal oxide scrubbers. Ambient measurements from a graphite scrubber-equipped photometer and a co-located Federal Equivalent Method (FEM) ozone analyzer showed excellent agreement over 38 days of measurements and indicated no loss in the scrubber’s ability to remove ozone when operated at 130 °C. The use of a heated graphite scrubber was found to reduce the interference from mercury vapor to ≤ 3 % of that obtained using a packed-bed Hopcalite scrubber. For a series of substituted aromatic compounds (ranging in volatility and absorption cross section at 253.7 nm), the graphite scrubber was observed to consistently exhibit reduced levels of interference, typically by factors of 2.5 to 20 less than with Hopcalite. Conventional solid-phase scrubbers also exhibited complex VOC adsorption and desorption characteristics that were dependent upon the relative humidity (RH), volatility of the VOC, and the available surface area of the scrubber. This complex behavior involving humidity is avoided by use of a heated graphite scrubber. These results suggest that heated graphite scrubbers could be substituted in most ozone photometers as a means of reducing interferences from other UV-absorbing species found in the atmosphere. This could be particularly important in ozone monitoring for compliance with the U.S. Clean Air Act or for use in monitoring indoor air quality.

Inhibition of Fungal Growth by Macerated Plant Tissues in a Closed Environment

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 476e-476
Author(s):  
Craig S. Charron ◽  
Catherine O. Chardonnet ◽  
Carl E. Sams
Keyword(s):  
Radial Growth ◽  
Fungal Pathogens ◽  
Solid Phase ◽  
Indian Mustard ◽  
Fungal Growth ◽  
Allyl Isothiocyanate ◽  
Pythium Ultimum ◽  
Alternative Methods ◽  
Gas Chromatography Mass Spectrometry ◽  
Clean Air

The U.S. Clean Air Act bans the use of methyl bromide after 2001. Consequently, the development of alternative methods for control of soilborne pathogens is imperative. One alternative is to exploit the pesticidal properties of macerated tissues of Brassica spp. This study tested the potential of several Brassica spp. for control of fungal pathogens. Pythium ultimum Trow or Rhizoctonia solani Kühn plugs on potato-dextrose agar on petri dishes were sealed in 500-ml glass jars (at 22 °C) containing macerated leaves (10 g) from one of six Brassica spp. Radial growth was measured 24, 48, and 72 h after inoculation. Indian mustard (B. juncea) was the most suppressive, followed by `Florida Broadleaf' mustard (B. juncea). Volatile compounds in the jars were sampled with a solid-phase microextraction device (SPME) and identified by gas chromatography-mass spectrometry (GC-MS). Allyl isothiocyanate (AITC) comprised over 90% of the total volatiles measured from Indian mustard and `Florida Broadleaf' mustard. Isothiocyanates were detected in jars with all plants except broccoli. (Z)-3-hexenyl acetate was emitted by all plants and was the predominant volatile of `Premium Crop' broccoli (B. oleracea L. var. italica), `Michihili Jade Pagoda' Chinese cabbage (B. pekinensis), `Charmant' cabbage (B. oleracea L. var. capitata), and `Blue Scotch Curled' kale (B. oleracea L. var. viridis). To assess the influence of AITC on radial growth of P. ultimum and R. solani, AITC was added to jars to give headspace concentrations of 0.10, 0.20, and 0.30 mg·L–1 (mass of AITC per volume of headspace). Growth of both fungi was inhibited by 0.10 mg·L–1 AITC. 0.20 mg·L–1 AITC was fungicidal to P. ultimum although the highest AITC level tested (0.30 mg·L–1) did not terminate R. solani growth. These results indicate that residues from some Brassica spp. may be a viable part of a soilborne pest control strategy.

INTEGRATING NANOSCALE ZERO-VALENT IRON AND TITANIUM DIOXIDE FOR NUTRIENT REMOVAL IN STORMWATER SYSTEMS

NANO ◽  
2008 ◽  
Vol 03 (04) ◽  
pp. 297-300 ◽  
Author(s):  
NI-BIN CHANG ◽  
MARTY WANIELISTA ◽  
FAHIM HOSSAIN ◽  
LEI ZHAI ◽  
KUEN-SONG LIN
Keyword(s):  
Titanium Dioxide ◽  
Water Reuse ◽  
Algal Blooms ◽  
Chemical Reduction ◽  
Nitrate Removal ◽  
Packed Bed ◽  
The United States ◽  
Zero Valent Iron ◽  
Nanoscale Zero Valent Iron ◽  
Freshwater Bodies

Nutrients, such as nitrate, nitrite, and phosphorus, are common contaminants in many aquatic systems in the United States. Ammonia and nitrate are both regulated by the drinking water standards in the US primarily because excess levels of nitrate might cause methemoglobinemia. Phosphorus might become sources of the eutrophication problems associated with toxic algae in the freshwater bodies. Toxic algal blooms can cause severe acute and chronic public health problems. Chemical reduction of nitrate by using zero-valent iron started as early as 1964, and considerable research reports relating to this technology to nanomaterial were extensively reported in 1990s making the use of nanoscale zero-valent iron (NZVI) particles for nitrate removal become one of the most popular technologies in this field. The purpose of the present study was to examine the potential of integrating green sorption media, such as sawdust, limestone, tire crumb, and sand/silt, with two types of nanoparticles, including NZVI and Titanium Dioxide ( TiO 2), for nitrate removal in an engineering process. The study consists of running packed bed column tests followed by the addition of NZVI and TiO 2 to improve nitrate and phosphorus removal efficiency. Preliminary results in this paper show that the potential and advanced study may support the creation of design criteria of stormwater and groundwater treatment systems for water reuse in the future.

Recent progress and prospects of polymeric hollow fiber membranes for gas application, water vapor and particulate matters removal

2021 ◽  
Author(s):  
Hui Shen Lau ◽  
Wai Fen Yong
Keyword(s):  
Water Vapor ◽  
Hollow Fiber ◽  
Recent Progress ◽  
Membrane Separation ◽  
Environmental Awareness ◽  
Separation Technique ◽  
Air Purification ◽  
Particulate Matters ◽  
Hollow Fiber Membranes ◽  
Clean Air

The increasing challenges in clean air demand have invigorated growing environmental awareness to secure effective air purification and separation technique. Membrane separation has drawn interdisciplinary attention and emerged as an...

scholarly journals A case study of convectively sourced water vapor observed in the overworld stratosphere over the United States

2017 ◽  
Vol 122 (17) ◽  
pp. 9529-9554 ◽  
Author(s):  
Jessica B. Smith ◽  
David M. Wilmouth ◽  
Kristopher M. Bedka ◽  
Kenneth P. Bowman ◽  
Cameron R. Homeyer ◽  
...  
Keyword(s):  
United States ◽  
Water Vapor ◽  
The United States

Introduction The Environment, the People, and the State: The Connecticut River Valley, 1790-7930

2001 ◽  
Author(s):  
John T. Cumbler
Keyword(s):  
New England ◽  
Pure Water ◽  
The United States ◽  
Environmental Crisis ◽  
Modern World ◽  
State Action ◽  
The Public ◽  
The People ◽  
Clean Air ◽  
Human Habitation

Early twentieth-century conservation in the United States has been identified in the public mind with the West and the protection of wilderness, parks, and national forests. Some scholars have explored conservation through the writings of naturalists and antimodernists like Henry David Thoreau. What we have only recently come to appreciate is that there was a whole generation of reformers very much concerned about the environment who were neither antimodernists nor wilderness protectors. They were modernists who rejected not the modern world, but the way the modern world was being fashioned. They did not retreat or long to retreat into the wilderness but lived in cities and towns. And they struggled to make the environment of the most settled parts of the nation more amenable to human habitation. It was in New England where these reformers first began to make their claims for the rights of citizens to clean air, clean water, and clean soil. The Massachusetts board of health argued, less than five years after the Civil War, for aggressive state action on the claim that “all citizens have an inherent right to the enjoyment of pure and uncontaminated air, and water, and soil, that this right should be regarded as belonging to the whole community, and that no one should be allowed to trespass upon it by his carelessness or his avarice.” And the New Hampshire board, in its first report, stated that “every person has a legitimate right to nature’s gifts—pure water, air, and soil—a right belonging to every individual, and every community upon which no one should be allowed to trespass through carelessness, ignorance, or other cause.” New England’s first environmental crisis was brought on by its people’s fecundity and by their material practices in the late eighteenth century. Out of that crisis emerged a changed New England with concentrated manufacturing centers and increasingly market-oriented agriculture. Although not all New Englanders enthusiastically supported this change all were affected by it. Within three generations, New Englanders saw their region transformed. That transformation created a new set of troubles. The emergence of those new problems, and the solutions nineteenthcentury Yankees offered, is the story of this book.

Variational Assimilation of Radar Data and GLM Lightning-Derived Water Vapor for the Short-Term Forecasts of High-Impact Convective Events

2019 ◽  
Vol 147 (11) ◽  
pp. 4045-4069 ◽  
Author(s):  
Alexandre O. Fierro ◽  
Yunheng Wang ◽  
Jidong Gao ◽  
Edward R. Mansell
Keyword(s):  
Water Vapor ◽  
Radar Data ◽  
The United States ◽  
High Impact ◽  
Added Value ◽  
Mixing Ratio ◽  
Short Term ◽  
Short Term Forecast ◽  
Term Forecast ◽  
Vapor Mass

Abstract The assimilation of water vapor mass mixing ratio derived from total lightning data from the Geostationary Lightning Mapper (GLM) within a three-dimensional variational (3DVAR) system is evaluated for the analysis and short-term forecast (≤6 h) of a high-impact convective event over the northern Great Plains in the United States. Building on recent work, the lightning data assimilation (LDA) method adjusts water vapor mass mixing ratio within a fixed layer depth above the lifted condensation level by assuming nearly water-saturated conditions at observed lightning locations. In this algorithm, the total water vapor mass added by the LDA is balanced by an equal removal outside observed lightning locations. Additional refinements were also devised to partially alleviate the seasonal and geographical dependence of the original scheme. To gauge the added value of lightning, radar data (radial velocity and reflectivity) were also assimilated with or without lightning. Although the method was evaluated in quasi–real time for several high-impact weather events throughout 2018, this work will focus on one specific, illustrative severe weather case wherein the control simulation—which did not assimilate any data—was eventually able to initiate and forecast the majority of the observed storms. Given a relatively reasonable forecast in the control experiment, the GLM and radar assimilation experiments were still able to improve the short-term forecast of accumulated rainfall and composite radar reflectivity further, as measured by neighborhood-based metrics. These results held whether the simulations made use of one single 3DVAR analysis or high-frequency (10 min) successive cycling over a 1-h period.

scholarly journals Simultaneous Determination of Zilpaterol and Other Beta Agonists in Calf Eye by Gas Chromatography/Tandem Mass Spectrometry

2003 ◽  
Vol 86 (1) ◽  
pp. 8-14 ◽  
Author(s):  
Beatrice Bocca ◽  
Maurizio Fiori ◽  
Claudia Cartoni ◽  
Gianfranco Brambilla
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Tandem Mass Spectrometry ◽  
Solid Phase ◽  
Growth Promotion ◽  
The United States ◽  
Meat Production ◽  
Tandem Mass ◽  
Retinal Tissue ◽  
Chromatography Tandem Mass Spectrometry

Abstract Adrenergic drugs for growth promotion have been outlawed in European meat production; however, molecules such as Ractopamine and Zilpaterol are licensed for feeding swine and cattle in the United States, Mexico, and South Africa. Analysis of bovine retinal extracts has recently shown considerable extension in the detection period following withdrawal. Previous studies demonstrated that residual concentrations of Clenbuterol and related substances in retinal tissue were >100 ng/g at day 50 of withdrawal. A method was developed to identify and simultaneously quantify Clenbuterol-like substances with anilinic moieties and drugs with phenolic and catecholic moieties, such as Ractopamine and Zilpaterol, in retinal tissue. The method was validated according to SANCO/1805/2000. After extraction in 0.1N HCl, samples were cleaned up on C18 non-endcapped solid-phase extraction columns and analyzed as trimethylchlorosilane derivatives by gas chromatography/tandem mass spectrometry, electron impact mode. At concentrations of agonists between 62.5 and 250.0 ng/g in bovine retina, mean recoveries ranged from 85.3 to 94.8%, repeatability was <9.6%, and within-laboratory reproducibility was <10.5%. The decision limits (CCα) were within the range of 66.3–70.4 ng/g, and the detection capability (CCβ) varied from 73.9 to 79.8 ng/g. Results are discussed in terms of a multiresidue approach to improve reliability of the monitoring strategy.

scholarly journals Novel Chromatographic Separation and Carbon Solid-Phase Extraction of Acetanilide Herbicide Degradation Products

2002 ◽  
Vol 85 (6) ◽  
pp. 1331-1337 ◽  
Author(s):  
Jody A Shoemaker
Keyword(s):  
Drinking Water ◽  
Solid Phase Extraction ◽  
Chromatographic Separation ◽  
Solid Phase ◽  
Degradation Products ◽  
The United States ◽  
Negative Ion ◽  
Phase Extraction ◽  
Herbicide Degradation ◽  
Relative Standard

Abstract One acetamide and 5 acetanilide herbicides are currently registered for use in the United States. Over the past several years, ethanesulfonic acid (ESA) and oxanilic acid (OA) degradation products of these acetanilide/acetamide herbicides have been found in U.S. ground waters and surface waters. Alachlor ESA and other acetanilide degradation products are listed on the U.S. Environmental Protection Agency's (EPA) 1998 Drinking Water Contaminant Candidate List. Consequently, EPA is interested in obtaining national occurrence data for these contaminants in drinking water. EPA currently does not have a method for determining these acetanilide degradation products in drinking water; therefore, a research method is being developed using liquid chromatography/negative ion electrospray/mass spectrometry with solid-phase extraction (SPE). A novel chromatographic separation of the acetochlor/alachlor ESA and OA structural isomers was developed which uses an ammonium acetate–methanol gradient combined with heating the analytical column to 70°C. Twelve acetanilide degradates were extracted by SPE from 100 mL water samples using carbon cartridges with mean recoveries >90% and relative standard deviations ≤16%.

scholarly journals Determination of N-Nitrosamines by Gas Chromatography Coupled to Quadrupole–Time-of-Flight Mass Spectrometry in Water Samples

Separations ◽  
2020 ◽  
Vol 7 (1) ◽  
pp. 3 ◽  
Author(s):  
Benigno José Sieira ◽  
Inmaculada Carpinteiro ◽  
Rosario Rodil ◽  
José Benito Quintana ◽  
Rafael Cela
Keyword(s):  
Mass Spectrometry ◽  
Environmental Protection Agency ◽  
Ion Trap ◽  
Solid Phase ◽  
Classical Method ◽  
Tap Water ◽  
Time Of Flight ◽  
The United States ◽  
Mass Analyzer

An analytical method based on high-resolution quadrupole–time-of-flight (QToF) mass spectrometry has been developed as an alternative to the classical method, using a low-resolution ion trap (IT) analyzer to reduce interferences in N-nitrosamines determination. Extraction of the targeted compounds was performed by solid-phase extraction (SPE) following the United States Environmental Protection Agency (USEPA) -521 method. First, both electron impact (EI) and positive chemical ionization (PCI) using methane as ionization gas were compared, along with IT and QToF detection. Then, parameters such as limits of detection (LOD) and quantification (LOQ), linearity, and repeatability were assessed. The results showed that the QToF mass analyzer combined with PCI was the best system for the determination of the N-nitrosamines, with instrumental LOD and LOQ in the ranges of 0.2–4 and 0.6–11 ng mL−1, respectively, which translated into method LOD and LOQ in the ranges of 0.2–1.3 and 0.6–3.9 ng L−1, respectively. The analysis of real samples showed the presence of 6 of the N-nitrosamines in influent, effluent, and tap water. N-nitrosodimethylamine (NDMA) was quantified in all the analyzed samples at concentrations between 1 and 27 ng L−1. Moreover, four additional nitrosamines were found in tap and wastewater samples.

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