Elucidating Contributions of Anthropogenic Volatile Organic Compounds and Particulate Matter to Ozone Trends over China

Environmental Science & Technology, Год журнала: 2022, Номер 56(18), С. 12906 - 12916

Опубликована: Сен. 9, 2022

In China, emissions of ozone (O3)-producing pollutants have been targeted for mitigation to reduce O3 pollution. However, the observed decrease is slower than/opposite expectations affecting health millions people. For a better understanding this failure and its connection with anthropogenic emissions, we quantify summer trends that would occurred had weather stayed constant by applying numerical tool "de-weathers" observations across 31 urban regions (123 cities 392 sites) over 8 years. are significant (p < 0.05) 234 sites after de-weathering, contrary directly (only 39 due high meteorology-induced variability). The de-weathered data allow categorizing in China into four different groups regarding mitigation, group 1 exhibiting steady reductions, while 4 showing increases. Analysis relationships between odd oxygen nitrogen oxides illustrates how changes NOx, volatile organic compounds (VOCs), reductions fine particulate matter (PM2.5) affect differently these groups. While analysis suggests VOC main driver decreases 1, 3 primarily affected decreasing PM2.5, which results enhanced formation. Our demonstrates both importance possibility isolating emission-driven from climate interpreting short-term air quality observations.

Язык: Английский

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Airborne Emission Rate Measurements Validate Remote Sensing Observations and Emission Inventories of Western U.S. Wildfires

Environmental Science & Technology, Год журнала: 2022, Номер 56(12), С. 7564 - 7577

Опубликована: Май 17, 2022

Carbonaceous emissions from wildfires are a dynamic mixture of gases and particles that have important impacts on air quality climate. Emissions feed atmospheric models estimated using burned area fire radiative power (FRP) methods rely satellite products. These approaches show wide variability large uncertainties, their accuracy is challenging to evaluate due limited aircraft ground measurements. Here, we present novel method estimate plume-integrated total carbon speciated emission rates unique combination lidar remote sensing aerosol extinction profiles in situ measured constituents. We strong agreement between these aircraft-derived detailed area-based inventory distributes time Geostationary Operational Environmental Satellite FRP observations (Fuel2Fire inventory, slope = 1.33 ± 0.04, r2 0.93, RMSE 0.27). Other more commonly used inventories strongly correlate with but wide-ranging over- under-predictions. A correlation found monoxide those derived the TROPOspheric Monitoring Instrument (TROPOMI) for five coincident sampling windows (slope 0.99 0.18; bias 28.5%). Smoke coefficients (g MJ–1) enable direct estimations primary gas observations, derive values many compounds emitted by temperate forest fuels, including several previously unreported species.

Язык: Английский

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Evaluating NO_x emissions and their effect on O₃ production in Texas using TROPOMI NO₂ and HCHO

Atmospheric chemistry and physics, Год журнала: 2022, Номер 22(16), С. 10875 - 10900

Опубликована: Авг. 26, 2022

Abstract. The Tropospheric Monitoring Instrument (TROPOMI) on the Sentinel-5 Precursor (S5P) satellite is a valuable source of information to monitor NOx emissions that adversely affect air quality. We conduct series experiments using 4×4 km2 Comprehensive Air Quality Model with Extensions (CAMx) simulation during April–September 2019 in eastern Texas evaluate multiple challenges arise from reconciling model simulations TROPOMI. find an increase NO2 (+17 % urban areas) when transitioning TROPOMI version 1.3 algorithm 2.3.1 Texas, greatest difference (+25 %) city centers and smaller differences (+5 less polluted areas. lightning contribute up 24 column areas over Gulf Mexico 8% inventories, locally resolved inputs, agree derived within 20 most circumstances, small underestimate Dallas–Fort Worth (−13 Houston (−20 %). In vicinity large power plant plumes (e.g., Martin Lake Limestone) we larger disagreements, i.e., consistently by 40 %–60 than modeled NO2, which incorporates measured stack emissions. having difficulty distinguishing attributed plants background concentrations – area atmospheric conditions cause short lifetimes. Second, NOx/NO2 ratio may be underestimated due 4 km grid cell size. To understand ozone formation regimes area, combine formaldehyde (HCHO) information. modest low biases relative HCHO, −9 −21 central lower biogenic volatile organic compound (VOC) Ozone at time early afternoon overpass are limited almost everywhere domain, except along Ship Channel, near Dallas/Fort International airport, presence undiluted plumes. There likely NOx-saturated morning hours cannot observe would well-suited for analysis HCHO upcoming TEMPO (Tropospheric Emissions: Pollution) mission. This study highlights measurements offer means validate inventories regimes, important limitations.

Язык: Английский

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Background nitrogen dioxide (NO₂) over the United States and its implications for satellite observations and trends: effects of nitrate photolysis, aircraft, and open fires

Atmospheric chemistry and physics, Год журнала: 2023, Номер 23(11), С. 6271 - 6284

Опубликована: Июнь 7, 2023

Abstract. Tropospheric nitrogen dioxide (NO2) measured from satellites has been widely used to track anthropogenic NOx emissions, but its retrieval and interpretation can be complicated by the free tropospheric NO2 background which satellite measurements are particularly sensitive. vertical column densities (VCDs) spaceborne Ozone Monitoring Instrument (OMI) averaged over contiguous US (CONUS) show no trend after 2009, despite sustained decreases in implying an important rising contribution background. Here, we use GEOS-Chem chemical transport model applied simulation of OMI better understand sources trends CONUS. The previous underestimate is largely corrected consideration aerosol nitrate photolysis, increases VCDs 13 % on annual basis (25 spring) also air mass factor (AMF) convert slant (SCDs) inferred spectra into 7 (11 spring). increase AMF retrieved observations, contributing improved agreement with model. Accounting for 2009–2017 aircraft emissions drives only a 1.4 mean CONUS 2 AMF, combination decreasing surface increasing expected drive 14 next decade that will necessary account trends. Fire smoke identification National Oceanic Atmospheric Administration (NOAA) Hazard Mapping System (HMS) indicates wildfires contribute 1 %–8 western June–September this since flattening Future analyses data infer must critically consider effects due aircraft, fires, possibly lightning.

Язык: Английский

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Space-Based Observations of Ozone Precursors within California Wildfire Plumes and the Impacts on Ozone-NO_x-VOC Chemistry

Environmental Science & Technology, Год журнала: 2023, Номер 57(39), С. 14648 - 14660

Опубликована: Сен. 13, 2023

The frequency of wildfires in the western United States has escalated recent decades. Here we examine impacts on ground-level ozone (O3) precursors and O3-NOx-VOC chemistry from source to downwind urban areas. We use satellite retrievals nitrogen dioxide (NO2) formaldehyde (HCHO, an indicator VOC) Tropospheric Monitoring Instrument (TROPOMI) track evolution O3 over California 2018 2020. improved these by updating a priori profiles explicitly accounting for effects smoke aerosols. TROPOMI observations reveal that extensive intense fire 2020 led overall increase statewide annual average HCHO NO2 columns 16% 9%. level offsets anthropogenic NOx emission reduction COVID-19 lockdown. enhancement within plumes is concentrated near regions actively burning, whereas far-reaching, extending areas due secondary production longer-lived VOCs such as ethene. Consequently, larger occurs NOx-limited regions, while greater VOC-limited areas, both contributing more efficient production.

Язык: Английский

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Estimating Hourly Nitrogen Oxide Emissions over East Asia from Geostationary Satellite Measurements

Environmental Science & Technology Letters, Год журнала: 2023, Номер 11(2), С. 122 - 129

Опубликована: Сен. 25, 2023

Bottom-up emission inventories of atmospheric nitrogen oxides (NOx = NO + NO2) are usually limited to annual updates and have large uncertainties. The recent launch the Geostationary Environmental Monitoring Spectrometer (GEMS) first provides hourly measurements trace gas pollutants from space, enabling new insights into diurnal variations in anthropogenic NOx emissions. In this study, we present an improved top-down estimation using GEMS NO2 observations characterize emissions over cities East Asia. We use Gaussian model polynomial fitting calculate lifetimes for several "point-source" then derive flux divergence method. show significant Systematic biases estimates found between GEMS-based estimations previous polar-orbiting satellites with a single daily overpass. Compared empirically factors, chemical simulations substantially reduce satellite surface (e.g., Wuhan, decreased by 31%). This study highlights essential role geostationary characterizing chemistry informing control policies.

Язык: Английский

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Model-free daily inversion of NOx emissions using TROPOMI (MCMFE-NOx) and its uncertainty: Declining regulated emissions and growth of new sources

Remote Sensing of Environment, Год журнала: 2023, Номер 295, С. 113720 - 113720

Опубликована: Июль 19, 2023

Язык: Английский

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Estimating surface NO2 concentrations over Europe using Sentinel-5P TROPOMI observations and Machine Learning

Remote Sensing of Environment, Год журнала: 2024, Номер 312, С. 114321 - 114321

Опубликована: Июль 24, 2024

Satellite observations from instruments such as the TROPOspheric Monitoring Instrument (TROPOMI) show significant potential for monitoring spatiotemporal variability of NO2, however they typically provide vertically integrated measurements over tropospheric column. In this study, we introduce a machine learning approach entitled 'S-MESH' (Satellite and ML-based Estimation Surface air quality at High resolution) that allows estimating daily surface NO2 concentrations Europe 1 km spatial resolution based on eXtreme gradient boost (XGBoost) model using primarily observation-based datasets period 2019–2021. Spatiotemporal used by include TROPOMI vertical column density, night light radiance Visible Infrared Imaging Radiometer Suite (VIIRS), Normalized Difference Vegetation Index Moderate Resolution Spectroradiometer (MODIS), stations European Environment Agency database modeled meteorological parameters planetary boundary layer height, wind velocity, temperature. The overall evaluation shows mean absolute error 7.77 μg/m3, median bias 0.6 μg/m3 Spearman rank correlation 0.66. performance is found to be influenced concentration levels, with most reliable predictions levels 10–40 <40%. temporal analyses indicate robustness across study area, better prediction accuracy during winter months associated higher concentrations. Despite complexity continental scale XGBoost-based fast execution in providing estimates Europe. Shapley Additive exPlanations (SHAP) value analysis highlights density main source information deriving concentrations, indicating its studies. SHAP values also importance anthropogenic emission proxy inputs VIIRS lights, complementing detailed patterns variations.

Язык: Английский

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Identifying missing sources and reducing NO_x emissions uncertainty over China using daily satellite data and a mass-conserving method

Atmospheric chemistry and physics, Год журнала: 2025, Номер 25(4), С. 2291 - 2309

Опубликована: Фев. 21, 2025

Abstract. This study applies a mass-conserving model-free analytical approach to daily observations on grid-by-grid basis of NO2 from the Tropospheric Monitoring Instrument (TROPOMI) rapidly and flexibly quantify changing emerging sources NOx emissions at high spatial temporal resolution. The inverted optimized underlying ranges include quantification atmospheric in situ processing, transport, physics. results are presented over three regions China, including Shandong Hubei, which urbanizing not frequently addressed global literature. day-to-day found be 1.96 ± 0.27 µg m−2 s−1 pixels with available priori values (1.94 s−1), while 1.22 0.63 extra inventory is lower than 0.3 s−1. Source attribution based thermodynamics combustion temperature, processing successfully identifies five different industrial source types. Emissions these sites adjacent Yangtze River 161. 68.9 Kt yr−1 (163 % higher priori), consistent missing light medium industries located along river, contradicting previous studies attributing water as emissions. Finally, reveal an uncertainty larger variability, providing quantitative information for placement future monitoring stations. It hoped that findings will drive new top-down estimates, quantified updated continuously consistently remotely sensed measurements associated uncertainties actively reflect land-use changes misidentified emissions, quantifying datasets inform bottom-up community.

Язык: Английский

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Biomass burning nitrogen dioxide emissions derived from space with TROPOMI: methodology and validation

Atmospheric measurement techniques, Год журнала: 2021, Номер 14(12), С. 7929 - 7957

Опубликована: Дек. 21, 2021

Abstract. Smoke from wildfires is a significant source of air pollution, which can adversely impact quality and ecosystems downwind. With the recently increasing intensity severity wildfires, threat to expected increase. Satellite-derived biomass burning emissions fill in gaps absence aircraft or ground-based measurement campaigns help improve online calculation as well inventories that feed models. This study focuses on satellite-derived NOx using high-spatial-resolution TROPOspheric Monitoring Instrument (TROPOMI) NO2 dataset. Advancements improvements satellite-based determination forest fire are discussed, including information plume height effects aerosol scattering absorption satellite-retrieved vertical column densities. Two common top-down emission estimation methods, (1) an exponentially modified Gaussian (EMG) (2) flux method, applied synthetic data determine accuracy sensitivity different parameters, wind fields, satellite sampling, noise, lifetime, spread. These tests show be accurately estimated single TROPOMI overpasses. The effect smoke aerosols columns (via mass factors, AMFs) estimated, these estimates compared observations four measuring plumes 2018 2019 North America. Our results indicate applying explicit correction improves agreement with (by about 10 %–25 %). aircraft- good within uncertainties. Both methods work well; however, EMG method seems output more consistent has better aircraft-derived emissions. Assuming shape for various plumes, we estimate average e-folding time 2 ±1 h observations. Based chemistry transport model simulations observations, net 1.3 1.5 times greater than A factor should thus used infer retrievals NO2.

Язык: Английский

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