Improving photochemical indicators for attributing ozone sensitivities in source apportionment analysis.

Comprehensive Air Quality Model with extensions (CAMx)-Decoupled Direct Method (DDM) simulations of first-order ozone (O3) sensitivity to nitrogen oxides (NOx) and volatile organic compounds (VOCs) emissions were performed and combined with modelled [Formula: see text] ratios to obtain a range of thresholds for determining O3-sensitivity regimes for different areas of China. Utilising the new threshold ranges for photochemical indicators, the method for determining O3 formation in the Ozone Source Apportionment Technology (OSAT) module within CAMx was improved by a dynamically varied threshold of [Formula: see text] ratio. The O3 concentration contributions in the newly added transition regime were apportioned to NOx and VOCs emissions in proportion to the relationship between the [Formula: see text] ratio and first-order O3 sensitivity. The source contributions of O3 concentrations from different emission sectors from June to September 2019 were compared using the original and improved CAMx-OSAT. The results showed that the O3 concentration contributions changed significantly in the NOx-limited regime, with a maximum decrease of 21.89%, while the contributions increased by up to 7.57% in the VOC-limited regime, and were within 15 µg/m3 in the transition regime. The modified OSAT module enabled a more sophisticated attribution of O3 to precursor emissions and may have far-reaching implications for informing O3 pollution control policy.

The clinical and genetic characteristics of maternally inherited diabetes and deafness (MIDD) with mitochondrial m.3243A > G mutation: A 10-year follow-up observation study and literature review.

Maternally inherited diabetes and deafness (MIDD) is often caused by the m.3243A > G mutation in mitochondrial DNA. Unfortunately, the characteristics of MIDD, especially long-term outcomes and heteroplasmic changes, have not been well described previously. The purpose of this study was to describe the clinical and genetic features of a family with MIDD after 10 years of follow-up.A 33-year-old male patient with typical characteristics of MIDD, including early-onset diabetes, deafness, and low body mass index, was admitted to our department. Further investigation revealed that the vast majority of his maternal relatives suffered from diabetes with or without deafness. A detailed family history was then requested from the patient and a pedigree was constructed. The patient suspected of MIDD was screened for mutations using whole mitochondrial DNA sequencing. Candidate pathogenic variants were then validated in other family members through Sanger sequencing. The patient was diagnosed with MIDD, with inherited m.3243A > G mutation in the mitochondrially encoded tRNA leucine 1 (MT-TL1) gene, after 10 years of symptom onset. The patient was then treated with insulin and coenzyme Q10 to improve mitochondrial function. During the follow-up period, his fasting blood glucose and HbA1c levels were improved and the incidence of diabetic ketoacidosis was significantly reduced. Our findings indicate that whole mitochondrial DNA sequencing should be considered for patients suspected of MIDD to improve the efficiency of diagnosis and prognosis.

Health effects of future dioxins emission mitigation from Chinese municipal solid waste incinerators.

Dioxins (including 2,3,7,8-tetrachlorodibenzo-p-dioxin, as Group 1 Carcinogen) in the atmosphere mainly originate from incomplete combustion during municipal solid waste (MSW) incineration. To significantly reduce dioxins emission from the MSW incineration industry, China has promulgated a set of ambitious plans regulating MSW-related pollution; however, the emission reduction potentials and concomitant environmental and health impacts associated with the implementation of these programs on a national scale remain unknown. Here, we use real measurements from official environmental impact assessment systems and continuous emissions monitoring systems (covering 96.6% of national MSW incinerators) to estimate unit-level dioxins emission and concomitant environmental and health impacts. We find that in 2018, 99.3% and 66.7% of Chinese incinerators met such concentration and temperature standards, respectively, controlling the total emissions to 19.6 g toxic equivalency quantity and maintaining carcinogenic and noncarcinogenic risks significantly below safety levels nationwide. Fully achieving both current standards and future regulations will reduce emissions and health risks by 67.7% and 62.6%, respectively, with waste sorting program contributing the majority. This study reveals substantial benefits from curbing MSW-related dioxins pollution and underscores the promise of ongoing management.

Formation processes and source contributions of ground-level ozone in urban and suburban Beijing using the WRF-CMAQ modelling system.

Beijing faces the challenge of high levels of ozone (O3) pollution. In this study, the Weather Research and Forecasting model and Community Multiscale Air Quality model (CMAQ) were used to simulate atmospheric O3 concentrations in Beijing. To investigate the formation mechanisms and source contributions of O3 pollution in different regions of Beijing, process analysis and the integrated source apportionment method within the CMAQ were applied to O3 concentrations in the summer of 2018. The process analysis results showed that vertical diffusion was the major contributor to O3 concentrations at all receptor sites in Beijing, at > 65.94 µg/(m3·hr). Gas-phase chemical reactions consumed a significant amount of O3 in urban and inner suburban areas (> -5.57 µg/(m3·hr)), while near-surface chemical reactions made positive contributions in outer suburban areas (> 4.72 µg/(m3·hr)). The O3 formation chemical reactions indicated that NO titration, which removes O3 at night-time, mainly occurred in urban areas. The weaker chemical reactions occurring near the surface in outer suburbs suggested that suburban-area O3 was produced in the upper atmospheric layers and was transported vertically to the lower layers. The O3 source apportionment results showed that boundary contributions were the dominant contributor to O3 pollution in Beijing (> 40%). The contribution of non-local emissions to O3 levels was significantly greater in the outer suburbs than in urban and inner suburban areas due to topography. This study increases the understanding of the complex processes of O3 formation in different areas of Beijing and informs the implementation of O3 control plans.

Impacts of springtime biomass burning in Southeast Asia on atmospheric carbonaceous components over the Beibu Gulf in China: Insights from aircraft observations.

Limited by the scarcity of in situ vertical observation data, the influences of biomass burning in Southeast Asia on major atmospheric carbonaceous compositions in downwind regions have not been thoroughly studied. In this study, aircraft observations were performed to obtain high time-resolved in situ vertical distributions of black carbon (BC) as well as carbon monoxide (CO) and carbon dioxide (CO2). Four types of profiles were revealed: Mode I (from 2000 to 3000 m, the BC, CO and CO2 concentrations were enhanced), Mode II (with increasing altitude, the BC, CO and CO2 concentrations almost decreased), Mode III (inhomogeneous vertical BC, CO and CO2 profiles with BC peaks were observed from 2500 to 3000 m) and Mode IV (the BC, CO and CO2 concentrations increased above 1500 m). Furthermore, simulations were conducted to calculate radiative forcing (RF) caused by BC and study the heating rate (HR) of BC in combination with the vertical BC profiles. A larger BC distribution in the atmosphere resulted in a sharp RF change from negative to positive values, imposing a nonnegligible influence on the atmospheric temperature profile, with maximum HR values ranging from 0.4 to 5.8 K/day. The values of the absorption Ångström exponent (AAE) were 1.46 ± 0.11 and 1.48 ± 0.17 at altitudes from 1000 to 2000 and 2000-3000 m, respectively. The average BC light absorption coefficient at the 370 nm wavelength (α BC (370)) accounted for 50.3 %-76.8 % of the α (370), while the brown carbon (BrC) light absorption coefficient at the 370 nm wavelength (α BrC (370)) contributed 23.2 %-49.7 % to the α (370) at altitudes of 1000-2000 m. At altitudes of 2000-3000 m, α BC (370) and α BrC (370) contributed 43.8 %-88.2 % and 11.8 %-56.2 % to the α (370), respectively. These findings show that calculations that consider the surface BC concentration but ignore the vertical BC distribution could result in massive uncertainties in estimating the RF and HR caused by BC. This study helped achieve a deeper understanding of the influences of biomass burning over the region of Southeast Asia on the profiles of atmospheric carbonaceous compositions and atmospheric BC absorption and its warming effect.

Heavy haze pollution during the COVID-19 lockdown in the Beijing-Tianjin-Hebei region, China.

To investigate the characteristics of particulate matter with an aerodynamic diameter less than 2.5 µm (PM2.5) and its chemical compositions in the Beijing-Tianjin-Hebei (BTH) region of China during the novel coronavirus disease (COVID-19) lockdown, the ground-based data of PM2.5, trace gases, water-soluble inorganic ions, and organic and elemental carbon were analyzed in three typical cities (Beijing, Tianjin, and Baoding) in the BTH region of China from 5-15 February 2020. The PM2.5 source apportionment was established by combining the weather research and forecasting model and comprehensive air quality model with extensions (WRF-CAMx). The results showed that the maximum daily PM2.5 concentration reached the heavy pollution level (>150 µg/m3) in the above three cities. The sum concentration of SO42-, NO3- and NH4+ played a dominant position in PM2.5 chemical compositions of Beijing, Tianjin, and Baoding; secondary transformation of gaseous pollutants contributed significantly to PM2.5 generation, and the secondary transformation was enhanced as the increased PM2.5 concentrations. The results of WRF-CAMx showed obviously inter-transport of PM2.5 in the BTH region; the contribution of transportation source decreased significantly than previous reports in Beijing, Tianjin, and Baoding during the COVID-19 lockdown; but the contribution of industrial and residential emission sources increased significantly with the increase of PM2.5 concentration, and industry emission sources contributed the most to PM2.5 concentrations. Therefore, control policies should be devoted to reducing industrial emissions and regional joint control strategies to mitigate haze pollution.

Modeling of spatial and temporal variations of ozone-NOx-VOC sensitivity based on photochemical indicators in China.

Comprehensive air quality model with extensions (CAMx)-decoupled direct method (DDM) was used to simulate ozone-NOx-VOCs sensitivity of for May-November in 2016-2018 in China. Based on the relationship between the simulated ozone (O3) sensitivity values and the ratio of formaldehyde (HCHO) to NO2 (FNR) and the ratio of production rate of hydrogen peroxide (H2O2) to production rate of nitric acid (HNO3) ( [Formula: see text] ), the localized range of FNR and [Formula: see text] thresholds in different regions in China were obtained. The overall simulated FNR values are about 1.640-2.520, and [Formula: see text] values are about 0.540-0.830 for the transition regime. Model simulated O3 sensitivities or region specific FNR or [Formula: see text] thresholds should be applied to ensure the accurate local O3 sensitivity regimes. Using the tropospheric column FNR values from ozone monitoring instrument (OMI) satellite data as an indicator with the simulated threshold values, the spatial distributions of O3 formation regimes in China are determined. The O3 sensitivity regimes from eastern to central China are gradually from VOC-limited, transition to NOx-limited spatially, and moving toward to transition or NOx-limited regime from 2005 to 2019 temporally.

Fast Approximation of Coherence for Second-Order Noisy Consensus Networks.

It has been recently established that for second-order consensus dynamics with additive noise, the performance measures, including the vertex coherence and network coherence defined, respectively, as the steady-state variance of the deviation of each vertex state from the average and the average steady-state variance of the system, are closely related to the biharmonic distances. However, direct computation of biharmonic distances is computationally infeasible for huge networks with millions of vertices. In this article, leveraging the implicit fact that both vertex and network coherence can be expressed in terms of the diagonal entries of pseudoinverse L2† of the square of graph Laplacian, we develop a nearly linear-time algorithm to approximate all diagonal entries of L2† , which has a theoretically guaranteed error for each diagonal entry. The key ingredient of our approximation algorithm is an integration of the Johnson-Lindenstrauss lemma and Laplacian solvers. Extensive numerical experiments on real-life and model networks are presented, which indicate that our approximation algorithm is both efficient and accurate and is scalable to large-scale networks with millions of vertices.

Coherence Scaling of Noisy Second-Order Scale-Free Consensus Networks.

A striking discovery in the field of network science is that the majority of real networked systems have some universal structural properties. In general, they are simultaneously sparse, scale-free, small-world, and loopy. In this article, we investigate the second-order consensus of dynamic networks with such universal structures subject to white noise at vertices. We focus on the network coherence HSO characterized in terms of the H2 -norm of the vertex systems, which measures the mean deviation of vertex states from their average value. We first study numerically the coherence of some representative real-world networks. We find that their coherence HSO scales sublinearly with the vertex number N . We then study analytically HSO for a class of iteratively growing networks-pseudofractal scale-free webs (PSFWs), and obtain an exact solution to HSO, which also increases sublinearly in N , with an exponent much smaller than 1. To explain the reasons for this sublinear behavior, we finally study HSO for Sierpinski gaskets, for which HSO grows superlinearly in N , with a power exponent much larger than 1. Sierpinski gaskets have the same number of vertices and edges as the PSFWs but do not display the scale-free and small-world properties. We thus conclude that the scale-free, small-world, and loopy topologies are jointly responsible for the observed sublinear scaling of HSO.

Discriminating Power of Centrality Measures in Complex Networks.

Centrality metrics are one of the most fundamental tools in social network analysis and network science, and various measures for evaluating node importance metrics have been devised. However, the crucial issue of testing the discriminating power of different centrality measures is still open. In this article, we propose to assess the discriminating power of node centrality measures by using the notion of automorphism and orbit: nodes in the same orbit have identical metric scores, while nodes in different orbits should have different centrality values. Under this assumption, we present a benchmark for the discriminating power of node centrality measures. Moreover, we propose an efficient approach to evaluate centrality measures in terms of the discriminating power, which is devoid of finding orbits. Extensive experiments on real and model networks are executed to compare seven commonly used node centrality metrics.

Pilot-Scale Airlift Bioreactor with Function-Enhanced Microbes for the Reduction of Refinery Excess Sludge.

A pilot-scale airlift bioreactor (ALBR) system was built and operated continuously for refinery excess sludge (RES) reduction. Combined ALBR and function-enhanced microbes (composed of photosynthetic bacteria and yeast) were integrated into the system. The pilot-scale ALBR was operated for 62 days, and the start-up time was 7 d. Continuous operation showed that the sludge reduction efficiency was more than 56.22%, and the water quality of the effluent was satisfactory. This study focused on investigating the effects of hydraulic retention time (HRT) on the stability of the system and the effect of sludge reduction. Under different HRT conditions of 40, 26.7, 20, and 16 h, the sludge reduction rates reached 56.22%, 73.24%, 74.09%, and 69.64%, respectively. The removal rates of chemical oxygen demand (COD) and total nitrogen (TN) decreased with decreasing HRT, whereas the removal rate of NH4+-N increased. The removal rate of total phosphorus (TP) was approximately 30%. Results indicate that the ALBR and function-enhanced microbe system can reduce sludge and treat sewage simultaneously, and the effluent is up to the national emission standard. Addition of function-enhanced microbes can promote the degradation of petroleum hydrocarbon substances in the sludge, especially alkanes with low carbon numbers. This study suggests that the optimal HRT for the system is 16 h. The total operation cost of the ALBR combined with the function-enhanced microbe system can be reduced by 50% compared with the cost of direct treatment of the RES system.

Removal of refractory organics in wastewater by coagulation/flocculation with green chlorine-free coagulants.

Coagulation/flocculation is considered an economical and practical technology to remove refractory organic matter from wastewater. Coagulants containing chlorine may release chloride ions into water, thereby resulting in corrosion. A green chlorine-free coagulant of polyaluminum ferric silicate (PSAF) was synthesized to treat non-oily (e.g., humus wastewater) and oily refractory wastewaters (e.g., lubricating oil wastewater). Results showed that the highest removal efficiency of humus substances in non-oily wastewater achieved 96.0% at pH 7.0 using PSAF alone. When treating oily wastewater, the dosage and addition sequence of PAMALAM significantly affected the coagulation performance. The removal efficiencies of turbidity, chemical oxygen demand, and total nitrogen were increased by 0.3, 1.8, and 5.9 folds, respectively, with the optimal adding sequence of PSAF +0.08% PAMALAM. More fulvic acid-like substances can be removed during this process. The analysis of zeta potential and floc properties revealed that charge neutralization, sweep, and adsorption/entrapment mechanisms existed during the single PSAF coagulation process, and PAMALAM mainly improved the adsorption, bridging, and sweep function.

Evaluating the meteorological normalized PM2.5 trend (2014-2019) in the "2+26" region of China using an ensemble learning technique.

In recent years, implementation of aggressive and strict clean air policies has resulted in significant decline in observed PM2.5 concentration in the Beijing-Tianjin-Hebei (BTH) region and its surrounding areas (i.e., the "2 + 26" region). To eliminate the effects of interannual and seasonal meteorological variation, and to evaluate the effectiveness of emission abatement policies, we applied a boosted regression tree model to remove confounding meteorological factors. Results showed that the annual average PM2.5 concentration normalized by meteorology for the "2 + 26" region declined by 38% during 2014-2019 (i.e., from 96 to 60 µg/m3); however, the BTH region exhibited the most remarkable decrease in PM2.5 concentration (i.e., a 60% reduction). Certain seasonal trend in normalized PM2.5 level remained for four target subregions owing to the effects of anthropogenic emissions in autumn and winter. Although strong interannual variations of meteorological conditions were unfavorable for pollutant dispersion during the heating seasons of 2016-2018, the aggressive abatement policies were estimated to have contributed to reductions in normalized PM2.5 concentration of 19%, 10%, 19%, and 17% in the BTH, Henan, Shandong, and Shanxi subregions, respectively. Our study eliminated the meteorological contribution to concentration variation and confirmed the effectiveness of the implemented clean air policies.

Bioelectrochemical remediation of Cr(VI)/Cd(II)-contaminated soil in bipolar membrane microbial fuel cells.

Heavy-metal contaminated soils post great environmental and health concerns. In this study, Cr and Cd which are frequently observed in contaminated soils, were selected as representatives of hazardous heavy metals because of their different redox potentials and electric charges. Cr(VI)-, Cd(II)-, Cr(VI)/Cd(II)-contaminated soils were remediated in two-chamber air-cathode MFCs, in order to investigate the remediation of soil contaminated by single heavy metal and mixed heavy metals. Four ion exchange membranes (IEMs) were first evaluated to find out that bipolar membrane (BPM) was able to well maintain pH in both anolyte and catholyte, which was beneficial to support biological metabolism and heavy metal removal. It was also found that heavy metal ions (Cr, Cd or Cr/Cd) could migrate toward the cathode forming a concentration gradient under the weak electric field. The interaction between negatively charged Cr and positively charged Cd had no major effect to hinder each other on the migration, suggesting that the reduction reaction and electric field should be the main motivation for metal ion migration. The remediation performance of mixed heavy metal contaminated soil was superior to that of single heavy metal contaminated soil, for the possible reason of smaller internal resistance under mixed heavy metal condition.

Directional culture of petroleum hydrocarbon degrading bacteria for enhancing crude oil recovery.

An oxygen-constrained system of crude oil reservoir environment was constructed to stimulate the growth of indigenous microbes, such as petroleum hydrocarbon-degrading bacteria. Addition of nitrogen and phosphorus sources was investigated for the growth of petroleum hydrocarbon-degrading bacteria. The results show that nitrates and phosphates stimulated the growth of the bacteria and promoted the biodegradation of crude oil as the sole carbon source in this process. The minimum surface tension was 29.63 mN/m when the amounts of the nitrogen (NaNO3: [Formula: see text]  = 2:1) and phosphorus (KH2PO4: NaH2PO4 = 5:2) sources added were 0.8 wt% and 1.4 wt%, respectively. Furthermore, the dominant petroleum hydrocarbon-degrading bacteria were shifted from Arcobacter in production water to Pseudomonas after the first subculture and then to Bacillus after the sixth subculture. The heteroatom groups in the crude oil were biodegraded simultaneously with normal alkanes and alkyl cyclohexanes. Addition of the nutrients resulted in microbial growth, microbial community shift, and enhanced microbial degradation.

Scale-Free Loopy Structure is Resistant to Noise in Consensus Dynamics in Complex Networks.

The vast majority of real-world networks are scale-free, loopy, and sparse, with a power-law degree distribution and a constant average degree. In this paper, we study first-order consensus dynamics in binary scale-free networks, where vertices are subject to white noise. We focus on the coherence of networks characterized in terms of the H 2 -norm, which quantifies how closely the agents track the consensus value. We first provide a lower bound of coherence of a network in terms of its average degree, which is independent of the network order. We then study the coherence of some sparse, scale-free real-world networks, which approaches a constant. We also study numerically the coherence of Barabási-Albert networks and high-dimensional random Apollonian networks, which also converges to a constant when the networks grow. Finally, based on the connection of coherence and the Kirchhoff index, we study analytically the coherence of two deterministically growing sparse networks and obtain the exact expressions, which tend to small constants. Our results indicate that the effect of noise on the consensus dynamics in power-law networks is negligible. We argue that scale-free topology, together with loopy structure, is responsible for the strong robustness with respect to noisy consensus dynamics in power-law networks.

Stimulation of indigenous microbes by optimizing the water cut in low permeability reservoirs for green and enhanced oil recovery.

Low permeability oil reservoirs are a widespread petroleum reservoir type all over the world. Therefore, methods to recover these reservoirs efficiently are of importance to guarantee energy supply. Here we report our novel stimulation of indigenous microbes by optimizing the water cut in low permeability reservoirs for green and enhanced oil recovery. We aimed to investigate the characteristics of indigenous bacterial communities with changes in water cut in reservoirs by high-throughput sequencing technology, and reveal the mechanism and characteristics of the crude oil biotreatment under different crude oil-water ratio conditions and the optimum activation time of indigenous functional microbial groups in reservoirs. The indigenous microbial metabolism products were characterized by gas chromatography mass spectrometry. Results showed that Acinetobacter (47.1%) and Pseudomones (19.8%) were the main functional genus of crude oil degradation at the optimal activation time, and can reduce the viscosity of crude oil from 8.33 to 5.75 mPa·s. The dominant bacteria genus for oil recovery after activation of the production fluids was similar to those in the reservoirs with water cut of 60-80%. Furthermore seven mechanism pathways of enhancing oil recovery by the synergistic of functional microbial groups and their metabolites under different water cut conditions in low permeability reservoirs have been established.

A cascade of a denitrification bioreactor and an aerobic biofilm reactor for heavy oil refinery wastewater treatment.

The performance of an efficient denitrification bioreactor-aerobic biofilm reactor cascade for heavy oil refinery wastewater treatment was investigated. Optimum operation parameters for denitrification were found as follows: (1) hydraulic retention time of 8 h; (2) C/NO3 --N molar ratio of 3.75 with acetate as the carbon source; (3) 20% (v/v) carrier filling ratio in the denitrification bioreactor. Under such optimal conditions, a volumetric removal of 0.82 kg N m-3 d-1 was obtained. As an alternative low-cost carbon source to acetate, secondary DAF effluent (COD/NO3 --N mass ratio of 5.4) was also detected and a stable activity of denitrification was achieved with adding 25% volume fraction of secondary DAF effluent. Effluent COD of the subsequent aerobic biofilm reactor further decreased satisfying the requirements of the current discharge standards. High-throughput sequencing results exhibited that Rhodocyclaceae and Comamonadaceae were the dominant denitrifiers in the denitrification reactor and Pseudomonas was the dominant microbe in the aerobic biofilm reactor.

Consensus in Self-Similar Hierarchical Graphs and Sierpinski Graphs: Convergence Speed, Delay Robustness, and Coherence.

The hierarchical graphs and Sierpinski graphs are constructed iteratively, which have the same number of vertices and edges at any iteration, but exhibit quite different structural properties: the hierarchical graphs are nonfractal and small-world, while the Sierpinski graphs are fractal and "large-world." Both graphs have found broad applications. In this paper, we study consensus problems in hierarchical graphs and Sierpinski graphs, focusing on three important quantities of consensus problems, that is, convergence speed, delay robustness, and coherence for first-order (and second-order) dynamics, which are, respectively, determined by algebraic connectivity, maximum eigenvalue, and sum of reciprocal (and square of reciprocal) of each nonzero eigenvalue of Laplacian matrix. For both graphs, based on the explicit recursive relation of eigenvalues at two successive iterations, we evaluate the second smallest eigenvalue, as well as the largest eigenvalue, and obtain the closed-form solutions to the sum of reciprocals (and square of reciprocals) of all nonzero eigenvalues. We also compare our obtained results for consensus problems on both graphs and show that they differ in all quantities concerned, which is due to the marked difference of their topological structures.

Cd(II) enhanced fluorescence and Zn(II) quenched fluorescence with phenylenevinylene terpyridine: A theoretical investigation.

Phenylenevinylene terpyridine (mepvpt) shows chelation enhanced fluorescence (CHEF) with Cd(II) and chelation quenched fluorescence (CHQF) with Zn(II), respectively. To understand the behaviors, we studied their intrinsic optical properties using DFT/TDDFT methods. The results show that fluorescence quantum yields (FQY) of mepvpt, mepvpt-Cd and mepvpt-Zn are low due to high ISC rates from higher excited states rather than the S1 excited state. When mepvpt chelates Cd(II), the molecular structure becomes more planar and S3,4 → S0 radiation rates become higher than that of mepvpt, which results in CHEF. When mepvpt chelates Zn(II), a new S4 → S0 emission with low oscillator strength occurs and high S4 → Tn ISC rates appear, which leads to CHQF. This proposed mechanism of metal fluorescence enhancing/quenching suggests a design strategy for single-molecular multi-analyte sensors.