A5048852015- Atmospheric chemistry and aerosols
- Air Quality and Health Impacts
- Atmospheric and Environmental Gas Dynamics
- Atmospheric Ozone and Climate
- Air Quality Monitoring and Forecasting
- Climate Change and Health Impacts
- Atmospheric aerosols and clouds
- Energy and Environment Impacts
- Vehicle emissions and performance
- Noise Effects and Management
- COVID-19 impact on air quality
- Urban Transport and Accessibility
- Global Health Care Issues
- Climate variability and models
- Environmental Justice and Health Disparities
- Health disparities and outcomes
- Energy, Environment, and Transportation Policies
- Marine and coastal ecosystems
- Geochemistry and Geologic Mapping
- Calibration and Measurement Techniques
- Mercury impact and mitigation studies
- Global Public Health Policies and Epidemiology
- Urban Green Space and Health
- Meteorological Phenomena and Simulations
- Sustainable Development and Environmental Policy
Washington University in St. Louis
2007-2025
Dalhousie University
2015-2025
Indian Institute of Technology Delhi
2024
Chinese Academy of Forestry
2023
South China Botanical Garden
2023
Research Institute of Tropical Forestry
2023
Center for Astrophysics Harvard & Smithsonian
2013-2022
Smithsonian Astrophysical Observatory
2004-2022
Columbia University
2022
Public Health Ontario
2013-2022
Exposure to ambient air pollution increases morbidity and mortality, is a leading contributor global disease burden. We explored spatial temporal trends in mortality burden of attributable from 1990 2015 at global, regional, country levels.
Exposure to ambient fine particulate matter (PM2.5) is a major global health concern. Quantitative estimates of attributable mortality are based on disease-specific hazard ratio models that incorporate risk information from multiple PM2.5 sources (outdoor and indoor air pollution use solid fuels secondhand active smoking), requiring assumptions about equivalent exposure toxicity. We relax these contentious by constructing PM2.5-mortality function only cohort studies outdoor covers the range....
The Georgia Institute of Technology–Goddard Global Ozone Chemistry Aerosol Radiation and Transport (GOCART) model is used to simulate the aerosol optical thickness τ for major types tropospheric aerosols including sulfate, dust, organic carbon (OC), black (BC), sea salt. GOCART uses a dust emission algorithm that quantifies source as function degree topographic depression, biomass burning includes seasonal interannual variability based on satellite observations. Results presented here show...
Epidemiologic and health impact studies of fine particulate matter with diameter < 2.5 microm (PM2.5) are limited by the lack monitoring data, especially in developing countries. Satellite observations offer valuable global information about PM2.5 concentrations.In this study, we developed a technique for estimating surface concentrations from satellite observations.We mapped ground-level using total column aerosol optical depth (AOD) MODIS (Moderate Resolution Imaging Spectroradiometer)...
Exposure to ambient air pollution is a major risk factor for global disease. Assessment of the impacts on population health and evaluation trends relative other factors requires regularly updated, accurate, spatially resolved exposure estimates. We combined satellite-based estimates, chemical transport model simulations, ground measurements from 79 different countries produce estimates annual average fine particle (PM2.5) ozone concentrations at 0.1° × spatial resolution five-year intervals...
We estimated global fine particulate matter (PM2.5) concentrations using information from satellite-, simulation- and monitor-based sources by applying a Geographically Weighted Regression (GWR) to geophysically based satellite-derived PM2.5 estimates. Aerosol optical depth multiple satellite products (MISR, MODIS Dark Target, SeaWiFS Deep Blue, MAIAC) was combined with simulation (GEOS-Chem) upon their relative uncertainties as determined ground-based sun photometer (AERONET) observations...
More than a decade of satellite observations offers global information about the trend and magnitude human exposure to fine particulate matter (PM2.5).In this study, we developed improved estimates ambient PM2.5 mass using concentrations inferred from multiple instruments.We combined three satellite-derived sources produce at 10 km × 1998 through 2012. For each source, related total column retrievals aerosol optical depth near-ground GEOS-Chem chemical transport model represent local...
We present a methodology for estimating the seasonal and interannual variation of biomass burning designed use in global chemical transport models. The average is estimated from 4 years fire‐count data Along Track Scanning Radiometer (ATSR) 1–2 similar Advanced Very High Resolution (AVHRR) World Fire Atlases. Total Ozone Mapping Spectrometer (TOMS) Aerosol Index (AI) product as surrogate to estimate variability six regions: Southeast Asia, Indonesia Malaysia, Brazil, Central America Mexico,...
Ambient air pollution is associated with numerous adverse health impacts. Previous assessments of global attributable disease burden have been limited to urban areas or by coarse spatial resolution concentration estimates. Recent developments in remote sensing, chemical-transport models, and improvements coverage surface measurements facilitate virtually complete spatially resolved pollutant We combined these data generate estimates long-term average ambient concentrations fine particles...
We use tropospheric NO 2 columns from the Global Ozone Monitoring Experiment (GOME) satellite instrument to derive top‐down constraints on emissions of nitrogen oxides (NO x ≡ + ), and combine these with a priori information bottom‐up emission inventory (with error weighting) achieve an optimized posteriori estimate global distribution surface emissions. Our GOME retrieval improves previous work by accounting for scattering absorption radiation aerosols; effect air mass factor (AMF) ranges...
Exposure to outdoor fine particulate matter (PM2.5) is a leading risk factor for mortality. We develop global estimates of annual PM2.5 concentrations and trends 1998-2018 using advances in satellite observations, chemical transport modeling, ground-based monitoring. Aerosol optical depths (AODs) from advanced products including finer resolution, increased coverage, improved long-term stability are combined related surface geophysical relationships between AOD simulated by the GEOS-Chem...
An accurate fine-resolution surface of the chemical composition fine particulate matter (PM2.5) would offer valuable information for epidemiological studies and health impact assessments. We develop geoscience-derived estimates PM2.5 from a transport model (GEOS-Chem) satellite observations aerosol optical depth, statistically fuse these with ground-based using geographically weighted regression over North America to produce spatially complete representation sulfate, nitrate, ammonium, black...
We evaluate the sensitivity of tropospheric OH, O 3 , and precursors to photochemical effects aerosols not usually included in global models: (1) aerosol scattering absorption ultraviolet radiation (2) reactive uptake HO 2 NO . Our approach is couple a 3‐D model chemistry (GEOS‐CHEM) with fields from (GOCART). Reactive by computed using reaction probabilities recent review (γ HO2 = 0.2, γ NO2 10 −4 NO3 −3 ). Aerosols decrease → O( 1 D) photolysis frequency 5–20% at surface throughout...
We use a global three‐dimensional model (GEOS‐CHEM) to better quantify the sources of elemental carbon (EC) and organic (OC) aerosols in United States through simulation year‐round observations for 1998 at network 45 sites (Interagency Monitoring Protected Visual Environments (IMPROVE)). Simulation with our best priori understanding sources, including satellite data constrain fire emissions, captures most variance (R 2 = 0.84 EC, 0.67 OC) low bias 15% EC 26% OC. Multiple linear regression...
Few cohort studies have evaluated the risk of mortality associated with long-term exposure to fine particulate matter [≤ 2.5 μm in aerodynamic diameter (PM(2.5))]. This is first national-level study investigate these risks Canada.We investigated association between ambient PM(2.5) and cardiovascular nonimmigrant Canadian adults.We assigned estimates derived from satellite observations a 2.1 million adults who 1991 were among 20% population mandated provide detailed census data. We identified...
We present a new formulation for the air mass factor (AMF) to convert slant column measurements of optically thin atmospheric species from space into total vertical columns. Because scattering, AMF depends on distribution species. formulate as integral relative (shape factor) over depth atmosphere, weighted by altitude‐dependent coefficients (scattering weights) computed independently radiative transfer model. The scattering weights are readily tabulated, and one can then obtain any...
We assess the relationship of ground‐level fine particulate matter (PM 2.5 ) concentrations for 2000–2001 measured as part Canadian National Air Pollution Surveillance (NAPS) network and U.S. Quality System (AQS), versus remote‐sensed PM determined from aerosol optical depths (AOD) by Moderate Resolution Imaging Spectroradiometer (MODIS) Multiangle (MISR) satellite instruments. A global chemical transport model (GEOS‐CHEM) is used to simulate factors affecting relation between AOD . AERONET...
Abstract. Soils have been identified as a major source (~15%) of global nitrogen oxide (NOx) emissions. Parameterizations soil NOx emissions (SNOx) commonly used in the current generation chemical transport models were designed to capture mean seasonal behaviour. These parameterizations do not, however, respond quantitatively meteorological triggers that are observed result pulsed SNOx. Here we present new parameterization SNOx implemented within model (GEOS-Chem). The represents available...
We present a retrieval of tropospheric nitrogen dioxide (NO 2 ) columns from the Global Ozone Monitoring Experiment (GOME) satellite instrument that improves in several ways over previous retrievals, especially accounting Rayleigh and cloud scattering. Slant columns, which are directly fitted without low‐pass filtering or spectral smoothing, corrected for an artificial offset likely induced by structure on diffuser plate GOME instrument. The stratospheric column is determined NO remote...
BackgroundFew studies examining the associations between long-term exposure to ambient air pollution and mortality have considered multiple pollutants when assessing changes in due residential mobility during follow-up.ObjectiveWe investigated cause-specific concentrations of fine particulate matter (≤ 2.5 μm; PM2.5), ozone (O3), nitrogen dioxide (NO2) a national cohort about million Canadians.MethodsWe assigned estimates annual these postal codes subjects for each year 16 years follow-up....
Annual global satellite-based estimates of fine particulate matter (PM2.5) are widely relied upon for air-quality assessment. Here, we develop and apply a methodology monthly uncertainties during the period 1998–2019, which combines satellite retrievals aerosol optical depth, chemical transport modeling, ground-based measurements to allow characterization seasonal episodic exposure, as well aid management. Many densely populated regions have their highest PM2.5 concentrations in winter,...