Comment on egusphere-2024-1680 DOI Creative Commons

Narendra Ojha

Published: Aug. 11, 2024

Abstract. Formaldehyde (HCHO) is an important air pollutant due to its direct health effects as toxic that contributes elevated cancer risk, role in ozone formation, and a product from oxidation of most gas phase reactive organic carbon. We make several updates affecting secondary production HCHO the Community Regional Atmospheric Chemistry Multiphase Mechanism (CRACMM) Multiscale Air Quality (CMAQ) model. Secondary isoprene monoterpenes increased, correcting underestimate current version. Simulated 2019 June–August surface during peak photochemical (11 am–3 pm) increased by 0.6 ppb (32 %) over southeastern US 0.2 (13 entire contiguous US. The compares more favorably with satellite-based observations TROPOMI aircraft campaign. Evaluation against hourly indicates missing nighttime sink for which can be ameliorated adding bidirectional exchange leaf wetness dependent deposition process increases deposition, decreasing nocturnal (8 pm–4 am) 1.1 (36 0.5 (29 ability CRACMM capture levels at midday improved, particularly sites northeastern US, while are improved though still lower than observed. Using established risk assessment methods, lifetime exposure U.S. population (~320 million) ambient predicted here may result 6200 cases, 40 % controllable anthropogenic emissions nitrogen oxides compounds. will available version 2 (CRACMM2) CMAQv5.5.

Language: Английский

Temperature-dependent emissions dominate aerosol and ozone formation in Los Angeles DOI
Eva Y. Pfannerstill, Caleb Arata, Qindan Zhu

et al.

Science, Journal Year: 2024, Volume and Issue: 384(6702), P. 1324 - 1329

Published: June 20, 2024

Despite declines in transportation emissions, urban North America and Europe still face unhealthy air pollution levels. This has challenged conventional understanding of the sources their volatile organic compound (VOC) precursors. Using airborne flux measurements to map emissions a wide range VOCs, we demonstrate that biogenic terpenoid contribute ~60% emitted VOC OH reactivity, ozone, secondary aerosol formation potential summertime Los Angeles this contribution strongly increases with temperature. implies control nitrogen oxides is key reducing ozone Angeles. We also show some anthropogenic increase temperature, which an effect not represented current inventories. Air mitigation efforts must consider climate warming will change emission amounts composition.

Language: Английский

Citations

38
Urban ozone formation and sensitivities to volatile chemical products, cooking emissions, and NOx upwind of and within two Los Angeles Basin cities DOI Creative Commons
Chelsea E. Stockwell, Matthew M. Coggon, Rebecca H. Schwantes

et al.

Atmospheric chemistry and physics, Journal Year: 2025, Volume and Issue: 25(2), P. 1121 - 1143

Published: Jan. 28, 2025

Abstract. Volatile chemical products (VCPs) and other non-traditional anthropogenic sources, such as cooking, contribute substantially to the volatile organic compound (VOC) budget in urban areas, but their impact on ozone formation is less certain. This study employs Lagrangian box modeling sensitivity analyses evaluate response sector-specific VOC nitrogen oxide (NOx) emissions two Los Angeles (LA) Basin cities during summer of 2021. The model simulated photochemical processing transport temporally spatially gridded from FIVE-VCP-NEI17NRT inventory accurately simulates variability magnitude O3, NOx, speciated VOCs Pasadena, CA. show that (AVOC) enhance mean daily maximum 8 h average Pasadena by 13 ppb, whereas biogenic (BVOCs) 9.4 ppb. Of influenced AVOCs, VCPs represent largest fraction at 45 %, while cooking fossil fuel are comparable 26 % 29 respectively. NOx along trajectory paths indicate regime varies temporally. modeled primarily NOx-saturated across dense core peak production Pasadena. Lowering 25 moves NOx-limited chemistry afternoon hours shrinks spatial extent saturation towards downtown LA. Further using represented a separate state requires steeper reductions transition sensitivity, further suggesting representing reactivity inventories critical determining effectiveness future reduction policies.

Language: Английский

Citations

1
Incorporating Cooking Emissions To Better Simulate the Impact of Zero-Emission Vehicle Adoption on Ozone Pollution in Los Angeles DOI Creative Commons
Qindan Zhu, Rebecca H. Schwantes, Chelsea E. Stockwell

et al.

Environmental Science & Technology, Journal Year: 2025, Volume and Issue: unknown

Published: March 12, 2025

Despite decades of emission control measures aimed at improving air quality, Los Angeles (LA) continues to experience severe ozone pollution during the summertime. We incorporate cooking volatile organic compound (VOC) emissions in a chemical transport model and evaluate it against observations order improve representation present-day regime LA. Using this updated model, we investigate impact adopting zero-emission vehicles (ZEVs) on with increased confidence. show that mitigating on-road gasoline through ZEV adoption would benefit both quality climate by substantially reducing anthropogenic nitrogen oxides (NOx) carbon dioxide (CO2) LA 28 41% summertime, respectively. This result moderate reduction O3 pollution, decreasing average number population-weighted exceedance days August from 9 6 days, shift majority LA, except for coastline, into NOx-limited regime. Our results also ZEVs diesel off-road further reduce an 1 day.

Language: Английский

Citations

1
On-Road Measurements of Nitrogen Oxides, CO, CO2, and VOC Emissions in Two Southwestern U.S. Cities DOI Creative Commons
Kristen Zuraski, Colin Harkins, Jeff Peischl

et al.

ACS ES&T Air, Journal Year: 2025, Volume and Issue: unknown

Published: March 18, 2025

Language: Английский

Citations

0
Laboratory Simulation Studies on Evaporative Fuel Loss from Storage Tanks DOI Creative Commons

N. Kapilan,

Kirthi Premnath,

D Varshitha

et al.

BIO Web of Conferences, Journal Year: 2025, Volume and Issue: 172, P. 01004 - 01004

Published: Jan. 1, 2025

The fossil fuel is used for various activities; however, it available in limited quantity and burning of causes global warming. loss from tanks volatile organic emission. When two-wheeler parked hot sun during summer, there evaporation the tanks. In this work, experimental work was carried out laboratory, to understand losses at temperature such as 35, 40 45 degree C. From observed that air significantly affects loss. increases with increase higher were 45-degree To simulate storage tank different level tank, experiments conducted beakers capacity 80, 100 200 mL which has surface area 101, 149 226 cm 2 . experiments, beaker. highest compared other areas. we suggest evaporative be minimized through appropriate mitigation measures.

Language: Английский

Citations

0
Optimizing Ozone Control Strategies for Chinese Megacity Clusters Under the Influence of Stratospheric Intrusion DOI
Kaihui Zhao, Wen Chen, P Lian

et al.

Journal of Geophysical Research Atmospheres, Journal Year: 2025, Volume and Issue: 130(8)

Published: April 12, 2025

Abstract Stratosphere intrusion (stratospheric (SI)), the largest natural source of ozone (O 3 ), poses a significant challenge for policymakers in developing effective O control strategies. Understanding emission reduction pathway under SI influence is crucial achieving long‐term attainment. However, role tropospheric pollution China remains poorly understood. To develop strategies, we employed localized comprehensive air quality model and Whole Atmosphere Community Climate Model. We found that contributions vary seasonally, peaking spring at lower latitudes then delays northward progressively as latitude increases, with peak higher occur June. Spatially, impacts surface most high‐latitude regions, decreasing latitudes. As ‐laden reaches surface, strategies become less effective, necessitating additional reductions. increase, optimal shifts: Beijing‐Tianjin‐Hebei Pearl River Delta regions during seasons from 2020 to 2023, it changes “VOC only” “NO x thresholds 13.57 8.39 ppb, respectively. For Yangtze Delta, Fenwei Plain, Chengyu, path optimal. This study provides valuable insights mitigate SI's negative effects.

Language: Английский

Citations

0
Role of chemical production and depositional losses on formaldehyde in the Community Regional Atmospheric Chemistry Multiphase Mechanism (CRACMM) DOI Creative Commons
T. Nash Skipper, Emma L. D’Ambro,

Forwood Wiser

et al.

Published: June 19, 2024

Abstract. Formaldehyde (HCHO) is an important air pollutant due to its direct health effects as toxic that contributes elevated cancer risk, role in ozone formation, and a product from oxidation of most gas phase reactive organic carbon. We make several updates affecting secondary production HCHO the Community Regional Atmospheric Chemistry Multiphase Mechanism (CRACMM) Multiscale Air Quality (CMAQ) model. Secondary isoprene monoterpenes increased, correcting underestimate current version. Simulated 2019 June–August surface during peak photochemical (11 am–3 pm) increased by 0.6 ppb (32 %) over southeastern US 0.2 (13 entire contiguous US. The compares more favorably with satellite-based observations TROPOMI aircraft campaign. Evaluation against hourly indicates missing nighttime sink for which can be ameliorated adding bidirectional exchange leaf wetness dependent deposition process increases deposition, decreasing nocturnal (8 pm–4 am) 1.1 (36 0.5 (29 ability CRACMM capture levels at midday improved, particularly sites northeastern US, while are improved though still lower than observed. Using established risk assessment methods, lifetime exposure U.S. population (~320 million) ambient predicted here may result 6200 cases, 40 % controllable anthropogenic emissions nitrogen oxides compounds. will available version 2 (CRACMM2) CMAQv5.5.

Language: Английский

Citations

2
Urban ozone formation and sensitivities to volatile chemical products, cooking emissions, and NOx across the Los Angeles Basin DOI Creative Commons
Chelsea E. Stockwell, Matthew M. Coggon, Rebecca H. Schwantes

et al.

Published: July 15, 2024

Abstract. Volatile chemical products (VCPs) and other non-traditional anthropogenic sources, such as cooking, contribute substantially to the volatile organic compound (VOC) budget in urban areas. The impact of these emissions on ozone formation atmospheric chemistry is uncertain. This study employs detailed Lagrangian box modeling sensitivity analyses evaluate response sector-specific VOC nitrogen oxide (NOx) Los Angeles (LA) Basin during summer 2021. model simulated photochemical processing transport temporally spatially gridded from FIVE-VCP-NEI17NRT inventory that combines fossil fuels, VCPs, point sources included updates cooking based recent field observations. accurately simulates variability magnitude O3 (hourly normalized mean bias = -0.03; R2 0.83), NOx, speciated VOCs measured at a ground site Pasadena, CA. show (AVOC) enhance daily maximum 8-hour average Pasadena by 12 ppb, whereas biogenic (BVOCs) 8 ppb. Of influenced AVOCs, VCPs represent largest fraction 44 % while fuel are comparable 28 each. first quantify contribution ozone. NOx along trajectory paths indicate regime varies temporally. modeled primarily NOx–saturated across dense core peak production but transitions back NOx–limited briefly late afternoon hours. Lowering 25 moves throughout majority day shrinks spatial extent NOx‒saturation towards downtown LA. Further using represented separate state requires steeper reductions transition NOx‒sensitivity, further suggesting representing reactivity inventories critical determine effectiveness future NOx‒reduction policies.

Language: Английский

Citations

2
Supplementary material to "Role of chemical production and depositional losses on formaldehyde in the Community Regional Atmospheric Chemistry Multiphase Mechanism (CRACMM)" DOI Open Access
T. Nash Skipper, Emma L. D’Ambro,

Forwood Wiser

et al.

Published: June 19, 2024

emissions Rx fires Prescribed (Rx) burning grass Grassland ag Agricultural rwc Residential wood combustion O&G point Point source oil and gas nonpt Area

Language: Английский

Citations

1
Role of chemical production and depositional losses on formaldehyde in the Community Regional Atmospheric Chemistry Multiphase Mechanism (CRACMM) DOI Creative Commons
T. Nash Skipper, Emma L. D’Ambro,

Forwood Wiser

et al.

Atmospheric chemistry and physics, Journal Year: 2024, Volume and Issue: 24(22), P. 12903 - 12924

Published: Nov. 21, 2024

Abstract. Formaldehyde (HCHO) is an important air pollutant with direct cancer risk and ozone-forming potential. HCHO sources are complex because both directly emitted produced from oxidation of most gas-phase reactive organic carbon. We update the secondary production in Community Regional Atmospheric Chemistry Multiphase Mechanism (CRACMM) Multiscale Air Quality (CMAQ) model. Production isoprene monoterpenes increased, correcting underestimate current version. Simulated June–August surface during peak photochemical (11:00–15:00 LT, local time) increased by 0.6 ppb (32 %) over southeastern USA 0.2 (13 contiguous USA. The compares more favorably satellite-based observations TROPOspheric Monitoring Instrument (TROPOMI) aircraft-based observations. Evaluation against hourly indicates a missing nighttime sink that can be improved deposition, which reduces nocturnal (20:00–04:00 LT) 1.1 (36 0.5 (29 ability CRACMM to capture levels at midday improved, particularly sites northeastern USA, while although still lower than observed. Using established assessment methods, lifetime exposure population (∼ 320 million) ambient predicted here may result 6200 cases, 40 % controllable anthropogenic emissions nitrogen oxides compounds. updates will available version 2 (CRACMM2) CMAQv5.5.

Language: Английский

Citations

1