Calculated Production Rates Research Articles

XYZ spectroscopy at electron-hadron facilities. III. Semi-inclusive processes with vector exchange

Inclusive production processes will be important for the first observations of XYZ states at new generation electron-hadron colliders, as they generally benefit from larger cross sections than their exclusive counterparts. We make predictions of semi-inclusive photoproduction of the χc1(1P) and X(3872), whose peripheral production is assumed to be dominated by vector exchanges. We validate the applicability of vector meson dominance in the axial-vector charmonium sector and calculate production rates at center-of-mass energies relevant for future experimental facilities. We find the semi-inclusive cross sections near the threshold to be enhanced by a factor of ∼2–3 compared to the exclusive reaction and well-suited for a first observation in photoproduction. Published by the American Physical Society 2024

Spatio-Temporal Analysis of Resources and Waste Quantities from Buildings (as Urban Mining Potential) Generated by the European Metropolis of Lille: A Methodology Coupling Data from Construction and Demolition Permits with Geographic Information Systems

The aim of this article was to conduct a spatial and territorial analysis of the urban mining potential of the European Metropolis of Lille (MEL), which had 1,174,273 inhabitants in 2018. This involved quantifying construction and demolition waste (CDW) deposits and analyzing their spatial distribution. The chosen quantification approach utilized building and demolition permits as input data, along with waste diagnostics for Construction and Building Materials Products (CBMPs) obtained from stakeholders in the building sector. Waste quantities were estimated using the production rate calculation method (GRC). Specifically, the calculation based on surface area combined with GIS geographic information systems. CDW quantities were categorized by demolition rehabilitation and construction; by type (hazardous non-hazardous inert); and by urban fabric. For the MEL area, the findings revealed that building sites covered the largest surface area, with over 8 million m² being constructed between 2013 and 2022. The construction activity, including renovation, is expected to constitute approximately 20% of the MEL’s building stock from 2013 to 2022. During the same period, 5.51% of the MEL’s building stock was demolished. This corresponds to nearly 6 million tons of CDW being generated during this period, averaging 661318 tons per year. Demolition sites contributed 73% of the total CDW production, compared to 22% for new construction and 4% for renovation sites. Inert waste continued to dominate the composition of waste, accounting for 90% of the total with 9% for non-hazardous waste and 1% for hazardous waste. Semi-detached and grouped houses business fabrics and townhouses or collective fabrics were identified as the primary type of waste-producing urban fabrics. Furthermore, our GIS-based methodology enabled the analysis of CDW quantity distribution by municipality, providing essential data for understanding the urban mining potential and the disparity between construction material requirements for new buildings and resources derived from building demolition. This approach facilitates the assessment of (1) a geographical area’s reliance on construction materials, and (2) the significance of reusing and recycling products equipment materials and waste (PEMW) in new construction to achieve circular economy objectives and to comply with the Extended Producer Responsibility (EPR) channel initiated in France in 2023. Over the period from 2013 to 2022, annual construction material requirements remained significantly higher than resources from building demolition and rehabilitation, ranging between 29% and 35%. Additionally, the analysis indicated a potential 41% rate of substitution of new construction materials with secondary primary materials in the MEL, varying by municipality and typology, with higher rates in rural communities and lower rates in urban communities.

Patient-specific automated cerebrospinal fluid pressure control to augment spinal wound closure: a case series using the LiquoGuard®

Objective Spinal cerebrospinal fluid (CSF) leaks are common, and their management is heterogeneous. For high-flow leaks, numerous studies advocate for primary dural repair and CSF diversion. The LiquoGuard7® allows automated and precise pressure and volume control, and calculation of patient-specific CSF production rate (prCSF), which is hypothesized to be increased in the context of durotomies and CSF leaks. Methods This single-centre illustrative case series included patients undergoing complex spinal surgery where: 1) a high flow intra-operative and/or post-operative CSF leak was expected and 2) lumbar CSF drainage was performed using a LiquoGuard7®. CSF diversion was tailored to prCSF for each patient, combined with layered spinal wound closure. Results Three patients were included, with a variety of pathologies: T7/T8 disc prolapse, T8-T9 meningioma, and T4-T5 metastatic spinal cord compression. The first two patients underwent CSF diversion to prevent post-op CSF leak, whilst the third required this in response to post-op CSF leak. CSF hyperproduction was evident in all cases (mean >/=140ml/hr). With patient-specific CSF diversion regimes, no cases required further intervention for CSF fistulae repair (including for pleural CSF effusion), wound breakdown or infection. Conclusions Patient-specific cerebrospinal fluid drainage may be a useful tool in the management of high-flow intra-operative and post-operative CSF leaks during complex spinal surgery. These systems may reduce post-operative CSF leakage from the wound or into adjacent body cavities. Further larger studies are needed to evaluate the comparative benefits and cost-effectiveness of this approach.

A Data Processing Methodology to Analyze Construction and Demolition Dynamics in the European Metropolis of Lille, France

In the absence of industry data, organisms, and researchers leverage free and available data, specifically building and demolition permits. Geospatial processing is essential to integrate information from various files into a single GIS layer containing all relevant attributes for analysis. This article proposes a Geographic Information System (GIS) processing model aimed at monitoring construction and demolition dynamics in the European metropolis of Lille to quantify the urban production of mineral waste from buildings. Author methodology is based on that that the deposit potential can be analyzed using the observation of the spatiotemporal dynamics of building and demolition permits. The results demonstrate that combining construction and demolition (C&D) permits with other GIS layers allows us to produce data to quantify demolition surfaces per year in a given French area. The applicability of this methodology extends to all French regions, providing insights into the impact of crises on deconstruction activities and C&D waste generation. The study focuses on C&D French public data bases (French government and European Metropolis of Lille) attributed to the region (area) of the European Metropolis of Lille (MEL) between 2013 and 2022. Some data for 2022 were incomplete due to ongoing treatment, emphasizing the importance of understanding the dynamics of demolition rates or surfaces to identify data gaps or errors. Historical trajectories of C&D permits were quantified and analyzed, revealing over 21,000 permits granted from 2013 to 2022, categorized by site type (new construction, rehabilitations, prior declarations, and demolitions). Construction sites during this period covered approximately 3,345,948 m2, constituting 20% of the MEL’s building stock, while demolition sites amounted to 1,977,911 m2, equivalent to 5% of the total area of buildings in the metropolis. Employing GIS allowed for a spatial analysis, visualizing data by municipality, urban fabric, and year. The analysis highlighted territories with high and low potential for demolition and construction, as well as the most impacted urban fabrics and dynamic periods. The article discusses potential crisis impacts (e.g., COVID-19 or economic downturns) and the implications of incomplete data. Finally, the study demonstrates how these findings can be utilized to quantify C&D waste, leveraging GIS and the production rate calculation method (GRC).

Reviewing 39Ar and 37Ar underground production in shallow depths with implications for groundwater dating

Argon-37 (37Ar) and Argon-39 (39Ar) are used for groundwater dating on timescales from weeks to centuries. For both isotopes, the quantification of underground sources is essential to accurately infer water residence times from sampled dissolved activities. Subsurface production resulting from interactions with neutrons from the natural radioactivity in rocks and with primary cosmogenic neutrons has been known for a long time. More recently, the capture of slow negative muons and reactions with muon-induced neutrons were documented for 39Ar subsurface production in the context of underground particle detectors (e.g. for Dark Matter research). However, the contribution from these particles was never considered for groundwater dating applications. Here, we reevaluate the importance of all potential depth-related production channels at depth ranges relevant for 39Ar groundwater dating [0 − 200 meters below the surface (m.b.s)]. The production of radioargon by muon-induced processes is considered in this depth range for the first time. The uncertainty on the total depth-dependent production rate is estimated with Monte Carlo simulations assuming a uniform distribution of the parameter uncertainties. This work aims to provide a comprehensive framework for interpreting 39Ar activities in terms of groundwater residence times and for exposure age dating of rocks. The production of 37Ar is also addressed since this isotope is relevant as a proxy for 39Ar production, for the timing of river-groundwater exchanges, and in the context of on-site inspections (OSI) within the verification framework of the Comprehensive Nuclear-Test-Ban Treaty (CTBT). In this perspective, we provide an interactive web-based application for the calculation of 37Ar and 39Ar production rates in rocks.

Operating algorithms of the "TRAP" automated group measuring device controller

The article highlights the importance of measuring the production capacity of wells (oil, water, gas) in the process of operation to ensure efficient development of oil and gas fields. Modernization of hardware and software by the Institute of Control Systems of "Trap"-type automated group measuring devices (AGMU), widely used in the oil fields of the Azerbaijan Republic, is demonstrated. An overall block diagram of the operating algorithms compiled during implementation of the new controller module in the upgraded "Trap" control device for measuring oil-well production rate as well as its separate sub-components are given: Initial parameter setting service; Automatic and manual query identification service; Manual command execution service; Service connecting (i)-th well to the measuring tank; Service of monitoring the filling of the tank over time (mi); Service of disconnecting (i)-th well from the measuring tank and waiting for fluid settling; Production rate measurement and calculation service; Automatic query analysis and execution service, their algorithms are described, and the principles of their operation are explained.

Observations of biogenic volatile organic compounds over a mixed temperate forest during the summer to autumn transition

Abstract. The exchange of trace gases between the biosphere and the atmosphere is an important process that controls both chemical and physical properties of the atmosphere with implications for air quality and climate change. The terrestrial biosphere is a major source of reactive biogenic volatile organic compounds (BVOCs) that govern atmospheric concentrations of the hydroxy radical (OH) and ozone (O3) and control the formation and growth of secondary organic aerosol (SOA). Common simulations of BVOC surface–atmosphere exchange in chemical transport models use parameterizations derived from the growing season and do not consider potential changes in emissions during seasonal transitions. Here, we use observations of BVOCs over a mixed temperate forest in northern Wisconsin during broadleaf senescence to better understand the effects of the seasonal changes in canopy conditions (e.g., temperature, sunlight, leaf area, and leaf stage) on net BVOC exchange. The BVOCs investigated here include the terpenoids isoprene (C5H8), monoterpenes (MTs; C10H16), a monoterpene oxide (C10H16O), and sesquiterpenes (SQTs; C15H24), as well as a subset of other monoterpene oxides and dimethyl sulfide (DMS). During this period, MTs were primarily composed of α-pinene, β-pinene, and camphene, with α-pinene and camphene dominant during the first half of September and β-pinene thereafter. We observed enhanced MT and monoterpene oxide emissions following the onset of leaf senescence and suggest that senescence has the potential to be a significant control on late-season MT emissions in this ecosystem. We show that common parameterizations of BVOC emissions cannot reproduce the fluxes of MT, C10H16O, and SQT during the onset and continuation of senescence but can correctly simulate isoprene flux. We also describe the impact of the MT emission enhancement on the potential to form highly oxygenated organic molecules (HOMs). The calculated production rates of HOMs and H2SO4, constrained by terpene and DMS concentrations, suggest that biogenic aerosol formation and growth in this region should be dominated by secondary organics rather than sulfate. Further, we show that models using parameterized MT emissions likely underestimate HOM production, and thus aerosol growth and formation, during early autumn in this region. Further measurements of forest–atmosphere BVOC exchange during seasonal transitions as well as measurements of DMS in temperate regions are needed to effectively predict the effects of canopy changes on reactive carbon cycling and aerosol production.

Short-chain fatty acid production in accessible and inaccessible body pools as assessed by novel stable tracer pulse approach is reduced by aging independent of presence of COPD

BackgroundProduction rates of the short-chain fatty acids (SCFA) acetate, propionate, and butyrate, which are beneficial metabolites of the intestinal microbiota, are difficult to measure in humans due to inaccessibility of the intestine to perform measurements, and the high first-pass metabolism of SCFAs in colonocytes and liver. We developed a stable tracer pulse approach to estimate SCFA whole-body production (WBP) in the accessible pool representing the systemic circulation and interstitial fluid. Compartmental modeling of plasma enrichment data allowed us to additionally calculate SCFA kinetics and pool sizes in the inaccessible pool likely representing the intestine with microbiota. We also studied the effects of aging and the presence of Chronic Obstructive Pulmonary Disease (COPD) on SCFA kinetics. MethodsIn this observational study, we designed a two-compartmental model to determine SCFA kinetics in 31 young (20–29 y) and 71 older (55–87 y) adults, as well as in 33 clinically stable patients with moderate to very severe COPD (mean (SD) FEV1, 46.5 (16.2)% of predicted). Participants received in the fasted state a pulse containing stable tracers of acetate, propionate, and butyrate intravenously and blood was sampled four times over a 30 min period. We measured tracer-tracee ratios by GC–MS and used parameters obtained from two-exponential curve fitting to calculate non-compartmental SCFA WBP and perform compartmental analysis. Statistics were done by ANCOVA. ResultsAcetate, propionate, and butyrate WBP and fluxes between the accessible and inaccessible pools were lower in older than young adults (all q < 0.0001). Moreover, older participants had lower acetate (q < 0.0001) and propionate (q = 0.019) production rates in the inaccessible pool as well as smaller sizes of the accessible and inaccessible acetate pools (both q < 0.0001) than young participants. WBP, compartmental SCFA kinetics, and pool sizes did not differ between COPD patients and older adults (all q > 0.05). Overall and independent of the group studied, calculated production rates in the inaccessible pool were on average 7 (acetate), 11 (propionate), and 16 (butyrate) times higher than non-compartmental WBP, and sizes of inaccessible pools were 24 (acetate), 31 (propionate), and 55 (butyrate) times higher than sizes of accessible pools (all p < 0.0001). ConclusionNon-compartmental production measurements of SCFAs in the accessible pool (i.e. systemic circulation) substantially underestimate the SCFA production in the inaccessible pool, which likely represents the intestine with microbiota, as assessed by compartmental analysis.

Entropy production in the inflationary epoch using the Gouy–Stodola theorem

In this work, we use the Gouy–Stodola theorem to calculate the entropy production rate in the inflationary epoch of the universe. This theorem allows us the simple calculation of entropy and entropy production rate occasioned by the decaying of the inflaton scalar field. Both the entropy and entropy production rate achieve large values, agreeing with the expected values present in the literature.

Photon production rate calculation from quark-gluon plasma using MEQM in heavy-ion collision

It is widely accepted that a huge and intense magnetic field is created along with the exotic state of matter in heavy-ion collision. The photon yield from quark-gluon plasma created in a magnetic environment is studied using a thermal quasi-particle mass. The quarks acquire this mass depending on the temperature and nonzero value of quark chemical potential which gets modified as magnetized effective quark mass (MEQM) in the presence of magnetic field. The total photon rate is shown for one loop process incorporating MEQM. It is found that the emission rate to lowest order increases strongly with increasing of the quark chemical potential and temperature. The enhanced yield in photon is also compared with the recently reported theoretical results.

Economic analysis of field crop production on a family farm

An economic analysis of field crop (wheat, corn, triticale and sunflower) production on a family farm, representing a case-study average farm, during one production year involved calculation of production costs, gross margin, economic efficiency and rate of profitability. Calculations showed that the highest amount of gross margin was achieved with corn, followed by sunflower, triticale and wheat. The calculated values of the coefficient of efficiency were in the respective order: 3.59 for corn, 2.16 for sunflower, 1.89 for triticale and 1.79 for wheat. The share of variable costs was also indicated, with special emphasis on high costs of mineral fertilizers and machinery.

Modeling of reconfigurable manufacturing system architecture with geometric machines and in-stage gantries

Reconfigurable Manufacturing Systems (RMSs) are well recognized by their capability to achieve high responsiveness and flexibility and are receiving increasing interest in today’s versatile manufacturing environment. This paper aims to develop methods to study the performance of RMS architecture consisting of machines and in-stage gantries whose time to failure and time to repair follow geometric distributions. A discrete-time Markov chain model is built to perform an exact analysis for two-stage-one-buffer systems. A decomposition method is developed to analyze multi-stage systems. Moreover, both time-dependent failure and operation-dependent failure modes are considered. Numerical studies that compare the calculated production rate and work-in-process to the simulation results demonstrate that the proposed methods can provide accurate results, especially for balanced systems and for systems with a small number of stages. The impact of different parameters (e.g., buffer capacity, machine/gantry reliability) on the production rate of the two models is also studied. Finally, examples on the applications of the models in the manufacturing systems design and operations are presented.

Observation of ambient NO3 radicals by LP-DOAS at a rural site in North China Plain

NO3 radicals can clean the atmospheric primary contaminants during the night. However, it can also effect the formation of secondary organic aerosol (SOA) and nitrate, which may worsen air quality. We report field observations of NO3 radicals with a home-made long path differential optical absorption spectroscopy (LP-DOAS) at a rural site in the polluted North China Plain in the summer of 2014. The detection limit (1σ) of NO3 with 3.4 km optical path was 3.4 ppt. The observed mean NO3 mixing ratios were 21 ppt with the maximum value of 104 ppt. The average calculated production rates and steady state lifetime of NO3 were 952 ppt/h and 103 s, respectively. The increase of both PM2.5 (>60 μg/m3) and RH (>60%) would result in an increase of the loss of NO3. The proportion of indirect losses rise with the increase of RH (>50%). The fitting kNO3 ranged from 0.0018 to 0.012 s−1 while γN2O5 was 0.0012 to 0.072. The ratios of direct loss ranged from 20.95% to 90.36% with an average of 56.81% during the campaign.

Atmospheric photooxidation and ozonolysis of Δ&amp;lt;sup&amp;gt;3&amp;lt;/sup&amp;gt;-carene and 3-caronaldehyde: rate constants and product yields

Abstract. The oxidation of Δ3-carene and one of its main oxidation products, caronaldehyde, by the OH radical and O3 was investigated in the atmospheric simulation chamber SAPHIR under atmospheric conditions for NOx mixing ratios below 2 ppbv. Within this study, the rate constants of the reaction of Δ3-carene with OH and O3 and of the reaction of caronaldehyde with OH were determined to be (8.0±0.5)×10-11 cm3 s−1 at 304 K, (4.4±0.2)×10-17 cm3 s−1 at 300 K and (4.6±1.6)×10-11 cm3 s−1 at 300 K, in agreement with previously published values. The yields of caronaldehyde from the reaction of OH and ozone with Δ3-carene were determined to be 0.30±0.05 and 0.06±0.02, respectively. Both values are in reasonably good agreement with reported literature values. An organic nitrate (RONO2) yield from the reaction of NO with RO2 derived from Δ3-carene of 0.25±0.04 was determined from the analysis of the reactive nitrogen species (NOy) in the SAPHIR chamber. The RONO2 yield of the reaction of NO with RO2 derived from the reaction of caronaldehyde with OH was found to be 0.10±0.02. The organic nitrate yields of Δ3-carene and caronaldehyde oxidation with OH are reported here for the first time in the gas phase. An OH yield of 0.65±0.10 was determined from the ozonolysis of Δ3-carene. Calculations of production and destruction rates of the sum of hydroxyl and peroxy radicals (ROx=OH+HO2+RO2) demonstrated that there were no unaccounted production or loss processes of radicals in the oxidation of Δ3-carene for conditions of the chamber experiments. In an OH-free experiment with added OH scavenger, the photolysis frequency of caronaldehyde was obtained from its photolytical decay. The experimental photolysis frequency was a factor of 7 higher than the value calculated from the measured solar actinic flux density, an absorption cross section from the literature and an assumed effective quantum yield of unity for photodissociation.

Potential Production of Carbon Gases and Their Responses to Paleoclimate Conditions: An Example From Xiaolongtan Basin, Southeast Tibetan Plateau

Uplift of the Tibetan Plateau plays a significant and lasting role in the variations of climate conditions and global carbon cycle. However, our knowledge is limited due to the lack of long-sequence records revealing rates of CO2 and CH4 production, hampering our understanding of the relationship between paleoclimatic conditions, carbon cycling and greenhouse gas flux. Here, we present a combination of paleoclimate records and low-temperature thermal simulation results from sediments of the Xiaolongtan Basin at the southeastern margin of the Qinghai-Tibetan Plateau, spanning the late Miocene (14.1 ∼ 11.6 Ma). The n-alkane-derived proxies suggested that the sources of organic matter were obviously different: a mixed source including lower organisms and terrestrial higher plants for the Dongshengqiao Formation from 14.1 to 12.6 Ma, and a predominant contribution from terrestrial higher plants for Xiaolongtan Formation between 12.6 and 11.6 Ma. The paleoclimate was generally warm and humid as reflected by the lipid biomarkers, consistent with previous studies. In addition, the carbon gases (including CO2 and hydrocarbon gases) generated by the low-temperature thermal simulation experiments indicated a production rate of CO2 and CH4 were as high as 88,000 ml/kg rock and 4,000 ml/kg rock, respectively, implying there were certain amounts of carbon gases generated and released into the atmosphere during their shallow burial stage. Besides, the calculated production rate of carbon gases and the estimated burial flux of organic carbon varied in response to the variations of paleoclimate conditions. Based on these observations, we propose that the climate conditions predominantly controlled the formation and accumulation of organic matter, which consequently affected the production of carbon gases and burial flux of organic carbon. The results presented here may provide a significant insight into the carbon cycle in the southeast of the Tibetan Plateau.

Galactic Cosmic Rays, Cosmic-Ray Variations, and Cosmogenic Nuclides in Meteorites

Abstract We present a new generation of model calculations for cosmogenic production rates in various types of solar system bodies. The model is based on the spectra for primary and secondary particles calculated using the INCL++6 code, which is the most reliable and most sophisticated code available for spallation reactions. Thanks to the recent improvements (extending the code to lower and higher energies and considering light charged particles as ejectiles and projectiles), we can for the first time directly consider primary and secondary Galactic α particles. We calculate production rates for 22Na, 10Be, and 26Al in an L-chondrite with a radius of 45 cm and in the Apollo 15 drill core, and we determine the long-term average Galactic cosmic-ray (GCR) spectrum (represented by the solar modulation potential Φ) in the meteoroid orbits at ∼3 au of Φ = 600 MV and at 1 au, i.e., for Earth and Moon of Φ = 660 MV. From this, we calculate a long-term average GCR gradient in the inner solar system of ∼5% au−1. Finally, we discuss the possibility of studying temporal GCR variations and meteoroid orbits using production rate ratios of short- and long-lived radionuclides.

Quantification of methane emissions from UK biogas plants

The rising number of operational biogas plants in the UK brings a new emissions category to consider for methane monitoring, quantification and reduction. Minimising methane losses from biogas plants to the atmosphere is critical not only because of their contribution of methane to global warming but also with respect to the sustainability of renewable energy production. Mobile greenhouse gas surveys were conducted to detect plumes of methane emissions from the biogas plants in southern England that varied in their size, waste feed input materials and biogas utilization. Gaussian plume modelling was used to estimate total emissions of methane from ten biogas plants based on repeat passes through the plumes. Methane emission rates ranged from 0.1 to 58.7 kg CH4 hr-1, and the percentage of losses relative to the calculated production rate varied between 0.02 and 8.1%. The average emission rate was 15.9 kg CH4 hr-1, and the average loss was 3.7%. In general, methane emission rates from smaller farm biogas plants were higher than from larger food waste biogas plants. We also suggest that biogas methane emissions may account for between 0.4 and 3.8%, with an average being 1.9% of the total methane emissions in the UK excluding the sewage sludge biogas plants.

NUCLEAR DATA SENSITIVITY/UNCERTAINTY PRE-ANALYSIS OF FNG WCLL FUSION BENCHMARK

To assure tritium self-sufficiency in future fusion reactors such as DEMO the accuracy of TRP calculations has to be demonstrated within the design uncertainties. A new neutronics experiment representing a mock-up of the Water Cooled Lithium Lead (WCLL) Test Blanket Module (TBM) is under preparation at the Frascati neutron generator (FNG) with the objective to provide an experimental validation of accuracy of nuclear data and neutron transport codes for the tritium production rate (TPR) calculations. The mock-up will consist of LiPb bricks, EUROFER plates and Perspex substituting water. The mock-up will be irradiated by 14 MeV neutrons at the FNG facility, and the TPR and detector reaction rates will be measured using Li2CO3 pellets and activation foils placed at different positions up to about 55 cm inside the mock-up. Computational pre-analyses for the design of the WCLL neutronics experiment using the SUSD3D sensitivity/uncertainty (S/U) code system is described and compared with the results of some similar FNG experiments performed in the past, in particular the FNG HCPB Tritium Breeder Module Mock-up (2005) and FNG-HCLL Tritium Breeder Module Mock-up (2009). The objective of the pre-analysis is to provide the calculated nuclear responses including the uncertainties due to the uncertainties in nuclear data and thus contributes to the optimisation of the design of the experimental set-up.

Elucidating the effect of HONO on O3 pollution by a case study in southwest China

Photolysis of nitrous acid (HONO) is one of the major sources for atmospheric hydroxyl radicals (OH), playing significant role in initiating tropospheric photochemical reactions for ozone (O3) production. However, scarce field investigations were conducted to elucidate this effect. In this study, a field campaign was conducted at a suburban site in southwest China. The whole observation was classified into three periods based on O3 levels and data coverage: the serious O3 pollution period (Aug 13–18 as P1), the O3 pollution period (Aug 22–28 as P2) and the clean period (Sep 3–12 as P3), with average O3 peak values of 96 ppb, 82 ppb and 44 ppb, respectively. There was no significant difference of the levels of O3 precursors (VOCs and NOx) between P1 and P2, and thus the evident elevation of OH peak values in P1 was suspected to be the most possible explanation for the higher O3 peak values. Considering the larger contribution of HONO photolysis to HOX primary production than photolysis of HCHO, O3 and ozonolysis of Alkenes, sensitivity tests of HONO reduction on O3 production rate in P1 are conducted by a 0-dimension model. Reduced HONO concentration effectively slows the O3 production in the morning, and such effect correlates with the calculated production rate of OH radicals from HONO photolysis. Higher HONO level supplying for OH radical initiation in the early morning might be the main reason for the higher O3 peak values in P1, which explained the correlation (R2 = 0.51) between average O3 value during daytime (10:00–19:00 LT) and average HONO value during early morning (00:00–05:00 LT). For nighttime accumulation, a suitable range of relative humidity that favored NO2 conversion within P1 was assumed to be the reason for the higher HONO concentration in the following early morning which promoted O3 peak values.

Role of the dew water on the ground surface in HONO distribution: a case measurement in Melpitz

Abstract. To characterize the role of dew water for the ground surface HONO distribution, nitrous acid (HONO) measurements with a Monitor for AeRosols and Gases in ambient Air (MARGA) and a LOng Path Absorption Photometer (LOPAP) instrument were performed at the Leibniz Institute for Tropospheric Research (TROPOS) research site in Melpitz, Germany, from 19 to 29 April 2018. The dew water was also collected and analyzed from 8 to 14 May 2019 using a glass sampler. The high time resolution of HONO measurements showed characteristic diurnal variations that revealed that (i) vehicle emissions are a minor source of HONO at Melpitz station; (ii) the heterogeneous conversion of NO2 to HONO on the ground surface dominates HONO production at night; (iii) there is significant nighttime loss of HONO with a sink strength of 0.16±0.12 ppbv h−1; and (iv) dew water with mean NO2- of 7.91±2.14 µg m−2 could serve as a temporary HONO source in the morning when the dew droplets evaporate. The nocturnal observations of HONO and NO2 allowed the direct evaluation of the ground uptake coefficients for these species at night: γNO2→HONO=2.4×10-7 to 3.5×10-6, γHONO,ground=1.7×10-5 to 2.8×10-4. A chemical model demonstrated that HONO deposition to the ground surface at night was 90 %–100 % of the calculated unknown HONO source in the morning. These results suggest that dew water on the ground surface was controlling the temporal HONO distribution rather than straightforward NO2–HONO conversion. This can strongly enhance the OH reactivity throughout the morning time or in other planted areas that provide a large amount of ground surface based on the OH production rate calculation.