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At least 307 records · Page 17
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on Pm3Nd by Materials Project

Pm3Nd is Magnesium-derived structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. Pm is bonded to eight equivalent Pm and four equivalent Nd atoms to form PmPm8Nd4 cuboctahedra that share corners with four equivalent NdPm12 cuboctahedra, corners with fourteen equivalent PmPm8Nd4 cuboctahedra, edges with six equivalent NdPm12 cuboctahedra, edges with twelve equivalent PmPm8Nd4 cuboctahedra, faces with four equivalent NdPm12 cuboctahedra, and faces with sixteen equivalent PmPm8Nd4 cuboctahedra. There are two shorter (3.66 Å) and six longer (3.68 Å) Pm–Pm bond lengths. There are two shorter (3.67 Å) and two longer (3.68 Å) Pm–Nd bond lengths. Nd is bonded to twelve equivalent Pm atoms to form NdPm12 cuboctahedra that share corners with six equivalent NdPm12 cuboctahedra, corners with twelve equivalent PmPm8Nd4 cuboctahedra, edges with eighteen equivalent PmPm8Nd4 cuboctahedra, faces with eight equivalent NdPm12 cuboctahedra, and faces with twelve equivalent PmPm8Nd4 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on PmNp by Materials Project

NpPm is Magnesium-derived structured and crystallizes in the hexagonal P-6m2 space group. The structure is three-dimensional. Np is bonded to six equivalent Np and six equivalent Pm atoms to form NpPm6Np6 cuboctahedra that share corners with eighteen equivalent NpPm6Np6 cuboctahedra, edges with six equivalent NpPm6Np6 cuboctahedra, edges with twelve equivalent PmPm6Np6 cuboctahedra, faces with eight equivalent NpPm6Np6 cuboctahedra, and faces with twelve equivalent PmPm6Np6 cuboctahedra. All Np–Np bond lengths are 3.37 Å. All Np–Pm bond lengths are 3.55 Å. Pm is bonded to six equivalent Np and six equivalent Pm atoms to form PmPm6Np6 cuboctahedra that share corners with eighteen equivalent PmPm6Np6 cuboctahedra, edges with six equivalent PmPm6Np6 cuboctahedra, edges with twelve equivalent NpPm6Np6 cuboctahedra, faces with eight equivalent PmPm6Np6 cuboctahedra, and faces with twelve equivalent NpPm6Np6 cuboctahedra. All Pm–Pm bond lengths are 3.37 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Pm3Tm by Materials Project

TmPm3 is beta Cu3Ti-like structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. Tm is bonded to twelve equivalent Pm atoms to form TmPm12 cuboctahedra that share corners with six equivalent TmPm12 cuboctahedra, corners with twelve equivalent PmPm8Tm4 cuboctahedra, edges with eighteen equivalent PmPm8Tm4 cuboctahedra, faces with eight equivalent TmPm12 cuboctahedra, and faces with twelve equivalent PmPm8Tm4 cuboctahedra. There are six shorter (3.61 Å) and six longer (3.65 Å) Tm–Pm bond lengths. Pm is bonded to four equivalent Tm and eight equivalent Pm atoms to form PmPm8Tm4 cuboctahedra that share corners with four equivalent TmPm12 cuboctahedra, corners with fourteen equivalent PmPm8Tm4 cuboctahedra, edges with six equivalent TmPm12 cuboctahedra, edges with twelve equivalent PmPm8Tm4 cuboctahedra, faces with four equivalent TmPm12 cuboctahedra, and faces with sixteen equivalent PmPm8Tm4 cuboctahedra. There are a spread of Pm–Pm bond distances ranging from 3.62–3.67 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on PmTm by Materials Project

TmPm crystallizes in the hexagonal P-6m2 space group. The structure is three-dimensional. Tm is bonded to six equivalent Tm and six equivalent Pm atoms to form TmPm6Tm6 cuboctahedra that share corners with eighteen equivalent TmPm6Tm6 cuboctahedra, edges with six equivalent TmPm6Tm6 cuboctahedra, edges with twelve equivalent PmPm6Tm6 cuboctahedra, faces with eight equivalent TmPm6Tm6 cuboctahedra, and faces with twelve equivalent PmPm6Tm6 cuboctahedra. All Tm–Tm bond lengths are 3.61 Å. All Tm–Pm bond lengths are 3.57 Å. Pm is bonded to six equivalent Tm and six equivalent Pm atoms to form PmPm6Tm6 cuboctahedra that share corners with eighteen equivalent PmPm6Tm6 cuboctahedra, edges with six equivalent PmPm6Tm6 cuboctahedra, edges with twelve equivalent TmPm6Tm6 cuboctahedra, faces with eight equivalent PmPm6Tm6 cuboctahedra, and faces with twelve equivalent TmPm6Tm6 cuboctahedra. All Pm–Pm bond lengths are 3.61 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Pm3Dy by Materials Project

DyPm3 is beta Cu3Ti-like structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. Dy is bonded to twelve equivalent Pm atoms to form DyPm12 cuboctahedra that share corners with six equivalent DyPm12 cuboctahedra, corners with twelve equivalent PmPm8Dy4 cuboctahedra, edges with eighteen equivalent PmPm8Dy4 cuboctahedra, faces with eight equivalent DyPm12 cuboctahedra, and faces with twelve equivalent PmPm8Dy4 cuboctahedra. There are six shorter (3.63 Å) and six longer (3.65 Å) Dy–Pm bond lengths. Pm is bonded to four equivalent Dy and eight equivalent Pm atoms to form PmPm8Dy4 cuboctahedra that share corners with four equivalent DyPm12 cuboctahedra, corners with fourteen equivalent PmPm8Dy4 cuboctahedra, edges with six equivalent DyPm12 cuboctahedra, edges with twelve equivalent PmPm8Dy4 cuboctahedra, faces with four equivalent DyPm12 cuboctahedra, and faces with sixteen equivalent PmPm8Dy4 cuboctahedra. There are six shorter (3.64 Å) and two longer (3.66 Å) Pm–Pm bond lengths.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on PmSm by Materials Project

SmPm is Magnesium-derived structured and crystallizes in the hexagonal P-6m2 space group. The structure is three-dimensional. Sm is bonded to six equivalent Sm and six equivalent Pm atoms to form SmPm6Sm6 cuboctahedra that share corners with eighteen equivalent SmPm6Sm6 cuboctahedra, edges with six equivalent SmPm6Sm6 cuboctahedra, edges with twelve equivalent PmPm6Sm6 cuboctahedra, faces with eight equivalent SmPm6Sm6 cuboctahedra, and faces with twelve equivalent PmPm6Sm6 cuboctahedra. All Sm–Sm bond lengths are 3.65 Å. All Sm–Pm bond lengths are 3.66 Å. Pm is bonded to six equivalent Sm and six equivalent Pm atoms to form PmPm6Sm6 cuboctahedra that share corners with eighteen equivalent PmPm6Sm6 cuboctahedra, edges with six equivalent PmPm6Sm6 cuboctahedra, edges with twelve equivalent SmPm6Sm6 cuboctahedra, faces with eight equivalent PmPm6Sm6 cuboctahedra, and faces with twelve equivalent SmPm6Sm6 cuboctahedra. All Pm–Pm bond lengths are 3.65 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on PmZr by Materials Project

PmZr crystallizes in the hexagonal P-6m2 space group. The structure is three-dimensional. Pm is bonded to six equivalent Pm and six equivalent Zr atoms to form PmPm6Zr6 cuboctahedra that share corners with eighteen equivalent PmPm6Zr6 cuboctahedra, edges with six equivalent PmPm6Zr6 cuboctahedra, edges with twelve equivalent ZrPm6Zr6 cuboctahedra, faces with eight equivalent PmPm6Zr6 cuboctahedra, and faces with twelve equivalent ZrPm6Zr6 cuboctahedra. All Pm–Pm bond lengths are 3.40 Å. All Pm–Zr bond lengths are 3.41 Å. Zr is bonded to six equivalent Pm and six equivalent Zr atoms to form ZrPm6Zr6 cuboctahedra that share corners with eighteen equivalent ZrPm6Zr6 cuboctahedra, edges with six equivalent ZrPm6Zr6 cuboctahedra, edges with twelve equivalent PmPm6Zr6 cuboctahedra, faces with eight equivalent ZrPm6Zr6 cuboctahedra, and faces with twelve equivalent PmPm6Zr6 cuboctahedra. All Zr–Zr bond lengths are 3.40 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on PmPa by Materials Project

PaPm crystallizes in the hexagonal P-6m2 space group. The structure is three-dimensional. Pa is bonded to six equivalent Pa and six equivalent Pm atoms to form PaPm6Pa6 cuboctahedra that share corners with eighteen equivalent PaPm6Pa6 cuboctahedra, edges with six equivalent PaPm6Pa6 cuboctahedra, edges with twelve equivalent PmPm6Pa6 cuboctahedra, faces with eight equivalent PaPm6Pa6 cuboctahedra, and faces with twelve equivalent PmPm6Pa6 cuboctahedra. All Pa–Pa bond lengths are 3.32 Å. All Pa–Pm bond lengths are 3.54 Å. Pm is bonded to six equivalent Pa and six equivalent Pm atoms to form PmPm6Pa6 cuboctahedra that share corners with eighteen equivalent PmPm6Pa6 cuboctahedra, edges with six equivalent PmPm6Pa6 cuboctahedra, edges with twelve equivalent PaPm6Pa6 cuboctahedra, faces with eight equivalent PmPm6Pa6 cuboctahedra, and faces with twelve equivalent PaPm6Pa6 cuboctahedra. All Pm–Pm bond lengths are 3.32 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Pm3Zn by Materials Project

Pm3Zn is beta Cu3Ti-like structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. Pm is bonded in a 12-coordinate geometry to eight equivalent Pm and four equivalent Zn atoms. There are a spread of Pm–Pm bond distances ranging from 3.31–3.72 Å. There are two shorter (3.28 Å) and two longer (3.52 Å) Pm–Zn bond lengths. Zn is bonded to twelve equivalent Pm atoms to form a mixture of face and corner-sharing ZnPm12 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Study of ${\mathrm{B}}_{\mathrm{s}}^0$ → J/ψπ + π – K + K – decays

The decays ${\mathrm{B}}_{\mathrm{s}}^0$ → J/ψπ + π – K + K – are studied using a data set corresponding to an integrated luminosity of 9 fb –1 , collected with the LHCb detector in proton-proton collisions at centre-of-mass energies of 7, 8 and 13 TeV. The decays ${\mathrm{B}}_{\mathrm{s}}^0$ → $\mathrm{J}/{ψ \mathrm{K}}^{\ast 0}{\overline{\mathrm{K}}}^{\ast 0}$ and ${\mathrm{B}}_{\mathrm{s}}^0$ → χ c1 (3872)K + K – , where the K + K – pair does not originate from a Φ meson, are observed for the first time. Precise measurements of the ratios of branching fractions between intermediate χ c1 (3872)Φ, $\mathrm{J}/{ψ \mathrm{K}}^{\ast 0}{\overline{\mathrm{K}}}^{\ast 0}$, ψ(2S)Φ and χ c1 (3872)K + K – states are reported. A structure, denoted as X(4740), is observed in the J/ψΦ mass spectrum and, assuming a Breit-Wigner parameterisation, its mass and width are determined to be ${\displaystyle \begin{array}{c}{m}_{\mathrm{X}(4740)}=4741\pm 6\pm 6\kern0.5em \mathrm{MeV}/{c}^2,\\ {}{\Gamma}_{\mathrm{X}(4740)}=53\pm 15\pm 11\kern0.5em \mathrm{MeV},\end{array}}$ where the first uncertainty is statistical and the second is systematic. In addition, the most precise single measurement of the mass of the ${\mathrm{B}}_{\mathrm{s}}^0$ meson is performed and gives a value of ${m}_{{\mathrm{B}}_{\mathrm{s}}^0}=5366.98\pm 0.07\pm 0.13\kern0.5em \mathrm{MeV}/{c}^2.$

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2026

Constraints on long-range forces in de Sitter space

The representation theory of de Sitter space admits partially massless (PM) particles, but whether such particles can participate in consistent interacting theories remains unclear. We investigate the consistency of theories containing PM fields, particularly when these fields are coupled to gravity. Our strategy exploits the fact that PM fields correspond to partially conserved currents on the spacetime boundary, which generate symmetries. These symmetries place stringent constraints on correlation functions of charged operators, allowing us to test the consistency of a proposed bulk spectrum. When the assumed operator content violates these constraints, the corresponding bulk theory is ruled out. Applying this framework, we show that, in four-dimensional de Sitter space, PM fields of spin 2 or 3 (at depth 0) cannot couple consistently to gravity: such couplings necessitate additional massive fields, which are inevitably non-unitary. In higher dimensions, however, the constraints can be satisfied without violating unitarity if further PM fields are included. The resulting structure leads to additional charge conservation laws, which suggests that consistency may ultimately require an infinite tower of higher-spin PM fields, akin to the situation for ordinary higher-spin symmetries. The methods developed here provide powerful constraints on possible long-range interactions in de Sitter space and delineate the landscape of consistent quantum field theories in cosmological spacetimes.

AdS-CFT Correspondence↗
DOE OSTI2024

Measurement of absolute branching fractions of $$ {\textrm{D}}_{\textrm{s}}^{+} $$ hadronic decays

Abstract Usinge + e − collision data collected at the BESIII detector at center-of-mass energies between 4.128 and 4.226 GeV, corresponding to an integrated luminosity of 7.33 fb −1 , we determine the absolute branching fractions of fifteen hadronic$$ {D}_s^{+} $$ D s + decays with a double-tag technique. In particular, we make precise measurements of the branching fractions$$ \mathcal{B}\left({D}_s^{+}\to {K}^{+}{K}^{-}{\pi}^{+}\right)=\left(5.49\pm 0.04\pm 0.07\right)\% $$ B D s + → K + K − π + = 5.49 ± 0.04 ± 0.07 % ,$$ \mathcal{B}\left({D}_s^{+}\to {K}_S^0{K}^{+}\right)=\left(1.50\pm 0.01\pm 0.01\right)\% $$ B D s + → K S 0 K + = 1.50 ± 0.01 ± 0.01 % and$$ \mathcal{B}\left({D}_s^{+}\to {K}^{+}{K}^{-}{\pi}^{+}{\pi}^0\right)=\left(5.50\pm 0.05\pm 0.11\right)\% $$ B D s + → K + K − π + π 0 = 5.50 ± 0.05 ± 0.11 % , where the first uncertainties are statistical and the second ones are systematic. TheCPasymmetries in these decays are also measured and all are found to be compatible with zero.

Physics↗
DOE OSTI2023

Measurement of Υ production in pp collisions at $\sqrt{s}$ = 5 TeV

The production cross-sections of Υ mesons, namely Υ(1S), Υ(2S) and Υ(3S), in pp collisions at $\sqrt{s}$ = 5 TeV are measured with a data sample corresponding to an integrated luminosity of 9.13 ± 0.18 pb –1 collected by the LHCb detector. The Υ mesons are reconstructed in the decay mode Υ → μ + μ – . Double differential cross-sections times branching fractions, as functions of the transverse momentum p T and the rapidity y of the Υ mesons, are measured in the range p T < 20 GeV/c and 2.0 < y < 4.5. The results integrated over these p T and y ranges are $\sigma \left(\textrm{Y}(1S)\right)\times \mathcal{B}\left(\textrm{Y}(1S)\to {\mu}^{+}{\mu}^{-}\right)=2101\pm 33\pm 83\ \textrm{pb},$ $\sigma \left(\textrm{Y}(2S)\right)\times \mathcal{B}\left(\textrm{Y}(2S)\to {\mu}^{+}{\mu}^{-}\right)=526\pm 20\pm 21\ \textrm{pb},$ $\sigma \left(\textrm{Y}(3S)\right)\times \mathcal{B}\left(\textrm{Y}(3S)\to {\mu}^{+}{\mu}^{-}\right)=242\pm 16\pm 10\ \textrm{pb},$ where the first uncertainties are statistical and the second are systematic. The ratios of cross-sections between measurements of two different Υ states and between measurements at different centre-of-mass energies are determined. The nuclear modification factor of Υ(1S) at $\sqrt{s}$ = 5 TeV is updated as well using the directly measured cross-section results from this analysis.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2024

Study of η′ → π+π−l+l− decays at BESIII

Abstract With a sample of (10087±44)×10 6 J/ψevents accumulated with the BESIII detector, we analyze the decaysη′→ π + π − l + l − (l=e, μ) via the processJ/ψ → γη′. The branching fractions are measured to be$$ \mathcal{B} $$ B (η′→ π + π − e + e − ) = (2.45±0.02(stat.)±0.08(syst.))×10 −3 and$$ \mathcal{B} $$ B (η′→ π + π − μ + μ − ) = (2.16±0.12(stat.)±0.06(syst.))×10 −5 , and the ratio is$$ \frac{\mathcal{B}\left({\eta}^{\prime}\to {\pi}^{+}{\pi}^{-}{e}^{+}{e}^{-}\right)}{\mathcal{B}\left({\eta}^{\prime}\to {\pi}^{+}{\pi}^{-}{\mu}^{+}{\mu}^{-}\right)}=113.4\pm 0.9\left(\textrm{stat}.\right)\pm 3.7\left(\textrm{syst}.\right) $$ B η ′ → π + π − e + e − B η ′ → π + π − μ + μ − = 113.4 ± 0.9 stat . ± 3.7 syst . . In addition, by combining theη′ →π + π − e + e − andη′ →π + π − μ + μ − decays, the slope parameter of the electromagnetic transition form factor is measured to beb η′ = 1.30 ± 0.19 (GeV/c 2 ) −2 , which is consistent with previous measurements from BESIII and theoretical predictions from the VMD model. The asymmetry in the angle between theπ + π − andl + l − decay planes, which has the potential to reveal theCP-violation originating from an unconventional electric dipole transition, is also investigated. The asymmetry parameters are determined to be$$ {\mathcal{A}}_{CP}\left({\eta}^{\prime}\to {\pi}^{+}{\pi}^{-}{e}^{+}{e}^{-}\right)=\left(-0.21\pm 0.73\left(\textrm{stat}.\right)\pm 0.01\left(\textrm{syst}.\right)\right)\% $$ A CP η ′ → π + π − e + e − = − 0.21 ± 0.73 stat . ± 0.01 syst . % and$$ {\mathcal{A}}_{CP}\left({\eta}^{\prime}\to {\pi}^{+}{\pi}^{-}{\mu}^{+}{\mu}^{-}\right)=\left(0.62\pm 4.71\left(\textrm{stat}.\right)\pm 0.08\left(\textrm{syst}.\right)\right)\% $$ A CP η ′ → π + π − μ + μ − = 0.62 ± 4.71 stat . ± 0.08 syst . % , implying that no evidence ofCP-violation is observed at the present statistics. Finally, an axion-like particle is searched for via the decayη′ →π + π − a, a→e + e − , and upper limits of the branching fractions are presented for the mass assumptions of the axion-like particle in the range of 0−500 MeV/c 2 .

Physics↗
DOE OSTI2020

Post-Minkowskian effective field theory for conservative binary dynamics

We develop an Effective Field Theory (EFT) formalism to solve for the conservative dynamics of binary systems in gravity via Post-Minkowskian (PM) scattering data. Our framework combines a systematic EFT approach to compute the deflection angle in the PM expansion, together with the ‘Boundary-to-Bound’ (B2B) dictionary introduced. Due to the nature of scattering processes, a remarkable reduction of complexity occurs both in the number of Feynman diagrams and type of integrals, compared to a direct EFT computation of the potential in a PM scheme. We provide two illustrative examples. Firstly, we compute all the conservative gravitational observables for bound orbits to 2PM, which follow from only one topology beyond leading order. The results agree with those, obtained through the ‘impetus formula’ applied to the classical limit of the one loop amplitude. For the sake of comparison we reconstruct the conservative Hamiltonian to 2PM order, which is equivalent to the one derived from a matching calculation. Secondly, we compute the scattering angle due to tidal effects from the electric- and magnetic-type Love numbers at leading PM order. Using the B2B dictionary we then obtain the tidal contribution to the periastron advance. We also construct a Hamiltonian including tidal effects at leading PM order. Although relying on (relativistic) Feynman diagrams, the EFT formalism developed here does not involve taking the classical limit of a quantum amplitude, neither integrals with internal massive fields, nor additional matching calculations, nor spurious (‘super-classical’) infrared singularities. By construction, the EFT approach can be automatized to all PM orders.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2025

Advancing Aerosol Chemical Characterization and Vertical Profiling over the Southern Great Plains Using Uncrewed Aerial Sampling and Offline Aerosol Mass Spectrometry

Recent advancements in uncrewed aerial systems (UASs) and particulate matter (PM) analytical techniques have provided opportunities for atmospheric research. In this study, we deployed the Department of Energy’s fixed-wing ArcticShark UAS to examine PM 2.5 composition at varying altitudes─within and above the planetary boundary layer (PBL)─over the Southern Great Plains atmospheric observatory (SGP). A total of 22 flights were conducted across March, June, and August 2023. Composite filter samples were collected during each flight and analyzed with offline aerosol mass spectrometry (AMS), complemented by on-board real-time sensors and ground-based instrumentation, to provide a comprehensive view of regional aerosol characteristics. Results show clear vertical and seasonal differences in the aerosol composition. Relative to ground-level measurements, aloft samples exhibited shifts in the distribution of organic and inorganic PM, with the organic composition varying distinctly across seasons. Particulate organic nitrogen (ON) was elevated, with bulk compositions similar in March and June but strongly altered in August, likely driven by biomass burning and enhanced photochemical activity. Combined AMS and chemical ionization mass spectrometry analyses detected amines, amides, and amino acids. PM above the planetary boundary layer was enriched in oxidized organic aerosols, while ground-level PM contained higher nitrate and sulfate. Seasonal differences in aqueous-phase processing were also observed, which were strongest in March during persistent cloud cover and weaker in the drier August period, suggesting a shift from aqueous- to gas-phase SOA formation. In conclusion, these findings highlight the value of UAS in advancing PM measurements and vertical profiling of aerosol composition.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2020

Effects of Low-Carbon Energy Adoption on Airborne Particulate Matter Concentrations With Feedbacks to Future Climate Over California

California plans to reduce emissions of long-lived greenhouse gases (GHGs) through adoption of new energy systems that will also lower concentrations of short-lived absorbing soot contained in airborne particulate matter (PM). Here we examine the direct and indirect effects of reduced PM concentrations under a low-carbon energy (GHG-Step) scenario on radiative forcing in California. Simulations were carried out using the source-oriented WRF/Chem (SOWC) model with 12 km spatial resolution for the year 2054. Furthermore, the avoided aerosol emissions due to technology advances in the GHG-Step scenario reduce ground level PM concentrations by ~8.85% over land compared to the Business-as-Usual (BAU) scenario, but changes to meteorological parameters are more modest. Top-of-atmospheric forcing predicted by the SOWC model increased by 0.15 W m -2 , surface temperature warmed by 0.001 K, and planetary boundary layer height (PBLH) increased by 2.20 cm in the GHG-Step scenario compared to the BAU scenario. PM climate feedbacks are small because the significant changes in ground level PM concentrations associated with the GHG-Step scenario are limited to the first few hundred meters of the atmosphere, with little change for the majority of the vertical column above that level. As an order-of-magnitude comparison, the long-term effects of global reductions in GHG emissions (RCP8.5–RCP4.5) lowered average surface temperature over the California study domain by approximately 0.76 K. The effects of long-lived climate pollutants such as CO 2 are much stronger than the effects of short-lived climate pollutants such as PM soot over California in the year 2054.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2026

Measured indoor PM2.5, black carbon, and oxidative potential before and after replacing gas with induction cooking in asthmatic households

Cooking is a major source of fine particulate matter (PM) in homes and evidence to date is inconclusive about the impact of cooking fuel on measures of residential PM exposure. The Cooking Energy and Ventilation Impacts on Children's Asthma (CEVICA) study measured cooking frequency, range hood use, indoor air quality (IAQ) and respiratory health indicators of children with asthma living in homes with gas stoves in California's San Joaquin Valley. Intensive measurements occurred over three 2-week intensive periods: at baseline and at the end of two consecutive 3-month study phases. Participants were randomly assigned to have their gas stoves replaced with electric induction at the start of Phase 1 or Phase 2. As part of the IAQ assessment, we collected particulate matter on Teflon filters using ultrasonic personal air samplers (UPAS). The filters were analyzed to quantify time-integrated PM 2.5 mass concentration, black carbon (BC) oxidative potential (OP). OP was measured using the SLF-OH assay, an acellular chemical assay that quantifies production of OH radicals in simulated lung fluid (SLF). Across all comparisons, PM 2.5 mass tended to be higher during gas cooking than induction electric cooking, although only one transition (Baseline to Phase 1) was statistically discernible at p<0.05. BC and mass-normalized OP showed no measurable differences across stove types or across phases. These preliminary findings suggest that stove fuel alone may not be the dominant determinant of indoor PM 2.5 concentrations in this sample, as previous studies have reported that indoor PM 2.5 during cooking can also be influenced by factors such as cooking practices, food and oil type, kitchen ventilation, and outdoor infiltration.

Lin, Zhuoying↗