A5101932810- Atmospheric chemistry and aerosols
- Air Quality and Health Impacts
- Atmospheric and Environmental Gas Dynamics
- Atmospheric Ozone and Climate
- Atmospheric aerosols and clouds
- Vehicle emissions and performance
- Air Quality Monitoring and Forecasting
- Fire effects on ecosystems
- Meteorological Phenomena and Simulations
- Environmental Policies and Emissions
- Climate variability and models
- Energy and Environmental Systems
- COVID-19 impact on air quality
- Wind and Air Flow Studies
- Criminal Law and Evidence
- Educational Reforms and Innovations
- Conflict of Laws and Jurisdiction
- Remote Sensing and Land Use
- Ionosphere and magnetosphere dynamics
- Medical Research and Treatments
- Spectroscopy and Laser Applications
- Social Acceptance of Renewable Energy
- Underground infrastructure and sustainability
- Maritime Navigation and Safety
- Urban and spatial planning
NOAA Air Resources Laboratory
2016-2025
University of Maryland, College Park
2015-2024
National Oceanic and Atmospheric Administration
2012-2024
Cooperative Institute for Climate and Satellites
2013-2020
Ajou University
2020
Gwangju Institute of Science and Technology
2020
George Mason University
2016
Korea Advanced Institute of Science and Technology
2015
University Research Co (United States)
2013
Earth Resources Technology (United States)
2011-2013
Abstract. The impact of regional emissions (e.g., domestic and international) on surface particulate matter (PM) concentrations in the Seoul metropolitan area (SMA), South Korea, its sensitivities to meteorology inventories are quantitatively estimated for 2014 using air quality modeling systems. Located downwind side strong sources anthropogenic emissions, Korea bears full transport pollutants their precursors. However, foreign has not yet been fully documented. We utilized two simulation...
Abstract Recent changes of surface particulate matter (PM) concentration in the Seoul Metropolitan Area (SMA), South Korea, are puzzling. The long-term trend PM SMA declined 2000s, but since 2012 its concentrations have tended to incline, which is coincident with frequent severe hazes Korea. This increase puts Korean government’s emission reduction efforts jeopardy. study reports that interannual variation Korea closely linked variations wind speed. A 12-year (2004–2015) regional air quality...
National emission inventories (NEIs) take years to assemble, but they can become outdated quickly, especially for time-sensitive applications such as air quality forecasting. This study compares multi-year NOx trends derived from satellite and ground observations uses these data evaluate the updates of by US Air Quality Forecast Capability (NAQFC) next-day ozone prediction during 2008 Global Economic Recession. Over eight large cities examined here, both Ozone Monitoring Instrument (OMI)...
This article presents the results of a detailed source apportionment study high particulate matter (PM) event in Seoul Metropolitan Area (SMA), South Korea, during late February 2014. Using Comprehensive Air Quality Model with Extensions its Particulate Source Apportionment Technology (CAMx-PSAT), we defined 10 regions, including five China, for spatially and chemically resolved analyses. During event, averaged PM10 concentration at all monitors SMA was 129 μg/m3, while PM2.5 concentrations...
This study identified the key chemical components based on an analysis of seasonal variations ground level PM2.5 concentrations and its major constituents (sulfate, nitrate, ammonium, organic carbon, elemental carbon) in Seoul Metropolitan Area (SMA), over a period five years, ranging from 2012 to 2016. It was found that mean concentration SMA 33.7 μg/m3, while inorganic ions accounted for 53% total mass concentration. The component ratio increased by up 61%–63% as daily increased. In...
Abstract The National Air Quality Forecasting Capability (NAQFC) upgraded its modeling system that provides developmental numerical predictions of particulate matter smaller than 2.5 μm in diameter (PM2.5) January 2015. issuance PM2.5 forecast guidance has become more punctual and reliable because are provided from the same produces operational ozone on Centers for Environmental Prediction (NCEP) supercomputers. There were three major upgrades 2015: 1) incorporation real-time intermittent...
In this study, we examined the change rates of PM2.5 concentrations, aerosol optical depth (AOD), and concentrations precursors, such as SO2 NO2, in China South Korea using surface satellite observations from 2015 to 2018. To quantify impacts emissions meteorology on concentration changes, performed a series air quality simulations with year-specific fixed anthropogenic inventory. The decreased at 9.1 4.3%/yr during study period, respectively. AODs Moderate Resolution Imaging...
The ability of an episcleral implant at the equator eye to deliver drugs posterior segment was evaluated, using a sustained-release containing gadolinium-DTPA (Gd-DTPA). movement this drug surrogate assessed with magnetic resonance imaging (MRI) in rabbit eye. results were compared similar placed vitreous cavity through scleral incision equator.Polymer-based implants releasing Gd-DTPA manufactured and subconjunctival space on episclera or live eyes (in vivo) freshly enucleated (ex vivo)....
Abstract. To show how remote-sensing products can be used to classify the entire CONUS domain into "geographical regions" and "chemical regimes", we analyzed results of simulation from Community Multiscale Air Quality (CMAQ) model version 4.7.1 over Conterminous United States (CONUS) for August 2009. In addition, observe these classifications capture weekly cycles ground-level nitrogen oxide (NOx) ozone (O3) at US EPA System (AQS) sites. We use Advanced Very High Resolution Radiometer...
Abstract. The National Air Quality Forecast Capability (NAQFC) project provides the US with operational and experimental real-time ozone predictions using two different versions of three-dimensional Community Multi-scale (CMAQ) modeling system. Routine evaluation near-real-time AIRNow measurements through 2011 showed better performance predictions. In this work, quality-controlled -assured System (AQS) nitrogen dioxide (NO2) observations are used to evaluate in 2010. It is found that both...
Abstract. This study applies the Gridpoint Statistical Interpolation (GSI) 3D-Var assimilation tool originally developed by National Centers for Environmental Prediction (NCEP), to improve surface PM2.5 predictions over contiguous United States (CONUS) assimilating aerosol optical depth (AOD) and in version 5.1 of Community Multi-scale Air Quality (CMAQ) modeling system. An optimal interpolation (OI) method implemented earlier (Tang et al., 2015) CMAQ system is also tested same period (July...
This study investigates long-term (i.e., 2007–2014) fluctuations in ambient ozone formation regimes for cities adjacent to shale plays the Northeast United States (U.S.). Ozone air quality many of U.S. does not meet National Ambient Air Quality Standards (NAAQS), and understanding is essential develop effective pollution mitigation strategies violating standards. Since 2013, has become world’s largest producer tight oil natural gas from rock, previous studies show that emissions pollutant...
We estimated long-term foreign contributions to the particulate matter of 2.5 μm or less in diameter (PM2.5) concentrations South Korea with a set air quality simulations. The Weather Research and Forecasting (WRF)-Sparse Matrix Operator Kernel Emissions (SMOKE)-Community Multiscale Air Quality (CMAQ) modeling system was used simulate base sensitivity case after 50% reduction emissions. effects horizontal grid resolutions (27- 9-km) also investigated. For this study, we chose PM2.5 during...
We employed an optimal interpolation (OI) method to assimilate AIRNow ozone/PM2.5 and MODIS (Moderate Resolution Imaging Spectroradiometer) aerosol optical depth (AOD) data into the Community Multi-scale Air Quality (CMAQ) model improve ozone total concentration for CMAQ simulation over contiguous United States (CONUS). assimilation was applied boundary layer, AOD were used adjust column aerosol. Four OI cases designed examine effects of uncertainty setting time; two these uncertainties that...
In this study, we address outdated emissions inventory problems in air quality forecasting systems. The National Emissions Inventory for NOx from area and mobile sources is projected 2005 to 2012 point 2010 2012, which find that area, reduce by 8.1%, 37.8% 4.1%, respectively. majority of the reduction occurs megacities over CONtiguous U.S. (CONUS), spatial distribution pattern generally supported NO2 column result retrieved GOME-2 satellite data. CMAQ-predicted O3 concentrations using...
Abstract. Accurate meteorological fields are imperative for correct chemical transport modeling. Observation nudging, along with objective analysis, is generally considered a low-cost and effective technique to improve simulations. However, the impact of observation nudging on chemistry has not been well characterized. This study involved two simulations analyze simulated meteorology ozone concentrations during 2013 Deriving Information Surface conditions from Column Vertically Resolved...
Fine-scale nitrogen oxide (NOx) concentrations over South Korea are examined using surface observations, satellite data and high-resolution model simulations based on the latest emission inventory. While accurate information NOx emissions in is crucial to understanding regional air quality region, consensus validation of lacking. We investigate spatial temporal variation fine-scale sources Korea. Surface observations newly available (TROPOspheric Monitoring Instrument; TROPOMI; 3.5 × 7 km2)...
Abstract In January 2020, anthropogenic emissions in Northeast Asia reduced due to the COVID-19 outbreak. When outdoor activities of public were limited, PM 2.5 concentrations China and South Korea between February March 2020 by − 16.8 μg/m 3 9.9 respectively, compared with average over previous three years. This study uses air quality modeling observations past four years separate influence reductions from meteorological changes emission control policies on this concentration change. Here,...
Abstract. Nitrogen dioxide vertical column density (NO2 VCD) measurements via satellite are compared with a fine-scale regional chemistry transport model, using new approach that considers varying footprint sizes. Space-borne NO2 VCD measurement has been used as proxy for surface nitrogen oxide (NOx) emission, especially anthropogenic urban so accurate comparison of and modeled is important in determining the future direction NOx emission policy. The NASA Ozone Monitoring Instrument (OMI)...
Abstract In this study, Moderate Resolution Imaging Spectroradiometer (MODIS) Aerosol Optical Depth (AOD) and AirNow PM 2.5 measurements are assimilated into the Community Multi‐scale Air Quality (CMAQ) model using an optimal interpolation (OI) method. Over a 30 day test period in July 2011, three assimilation configurations were used which MODIS AOD first separately before being simultaneously. The background error covariance is estimated both National Meteorological Center approach...
Abstract. Sixty days after the lockdown of Hubei Province, where coronavirus was first reported, China's true recovery from pandemic remained an outstanding question. This study investigates how human activity changed during this period using observations surface pollutants. By combining data with a three-dimensional chemistry model, impacts meteorological variations and in yearly emission control are minimized, demonstrating pollutant levels over China before Lunar New Year 2017 to 2020....