observing air quality from space
DESCRIPTION
Observing Air Quality from Space. With contributions from Mike Brauer: University of British Columbia Ralph Kahn, Rob Levy: NASA Goddard Paul Villeneuve: UofT, Health Canada. Randall Martin, Aaron van Donkelaar, Lok Lamsal, Chulkyu Lee, Carolyn Verduzco. Undergraduate Science Conference - PowerPoint PPT PresentationTRANSCRIPT
Observing Air Quality from SpaceObserving Air Quality from Space
Randall Martin, Aaron van Donkelaar, Lok Lamsal, Chulkyu Lee, Carolyn Verduzco
Undergraduate Science Conference25 September 2010
Dalhousie University
With contributions from Mike Brauer: University of British Columbia
Ralph Kahn, Rob Levy: NASA GoddardPaul Villeneuve: UofT, Health Canada
A Group EffortA Group Effort
Major Air Pollutants and Health EffectsMajor Air Pollutants and Health Effects
Key Pollutants that Contribute to Respiratory and Cardiovascular Illness
Fine Aerosol (PM2.5), Ozone (O3), Nitrogen Dioxide (NO2)
(AQHI)
Health Canada, Health Effects of Air Pollution
AQHI = f(NO2, O3, PM2.5)
Smog Alert, Toronto
Sources of Major Air PollutantsSources of Major Air Pollutants
Fires Biosphere Humanactivity
Nitric oxide (NO)Carbon monoxide (CO), Volatile organics (VOCs)
Ozone (O3) Hydroxyl (OH)sunlight
H2O, sunlight
Ammonia (NH3), Sulfur dioxide (SO2), NO, VOCs
oxidation
NH3, H2SO4, HNO3
Semivolatile Organics
Nucleation, Condensation,Coagulation
Mineral Dust
Aerosol
NO2
Sea Salt
Large Regions Have Insufficient In Situ Measurements Large Regions Have Insufficient In Situ Measurements for Air Quality Assessmentfor Air Quality Assessment
Canada Wide Standard (CWS): 3-year average of annual 98th percentile of the daily 24-hour average PM2.5 < 30 ug m-3
WHO standard 10 ug m-3 in annual mean
Sun-synchronous Polar Orbiting GeometrySun-synchronous Polar Orbiting Geometry
Sun-synchronous Polar Orbit
~14 orbits / day
VisibleVisible UltravioletUltraviolet
Photographs in thePhotographs in the
Satellite Observations of Tropospheric NOSatellite Observations of Tropospheric NO22
SCIAMACHY 2003-2005
Tropospheric NO2 (1015 molecules cm-2)
Martin et al., JGR, 2006
Method: Solar backscatter
Scattering by Earth surface and atmosphere
IdealizedNO2
absorptionspectrum
Visibility Impeded by Aerosol LoadingVisibility Impeded by Aerosol LoadingWaterton Lakes/Glacier National ParkWaterton Lakes/Glacier National Park
7.6 ug m-3 12 ug m-3
22 ug m-365 ug m-3
Malm, 1999
Aerosol Remote Sensing Aerosol Remote Sensing
Pollution haze over East Coast Dust off West Africa
a m sR R R R Aerosol Reflectance for specific wavelength and geometry
For dark scenes
measuredmolecular
surface
Aerosol optical thickness
aa
R
P
For small a single scattering albedo P(Θ) phase function
Aerosol Optical Thickness (Aerosol Optical Thickness (ττ)) from Satellite from SatelliteUsing MODIS and MISR Instruments over 2001-2006Using MODIS and MISR Instruments over 2001-2006
van Donkelaar et al., EHP, 2010
0.3
0.25
0.2
0.15
0.1
0.05
0
τ [u
nitle
ss]
Chemical Transport Model (GEOS-Chem) Chemical Transport Model (GEOS-Chem) Simulation of Aerosol Optical Depth Simulation of Aerosol Optical Depth
Aaron van Donkelaar
Ground-level PMGround-level PM2.52.5 = = ηη · ττ
η affected by vertical structure, aerosol properties, relative humidityObtain η from aerosol-oxidant model (GEOS-Chem) sampled coincidently with satellite obs
GEOS-Chem Simulation of η for 2001-2006
van Donkelaar et al., EHP, 2010
Significant Agreement with Coincident In situ MeasurementsSignificant Agreement with Coincident In situ Measurements
SatelliteDerived
In-situ
Sat
ellit
e-D
eriv
ed
[μg/
m3]
In-situ PM2.5 [μg/m3]
Ann
ual M
ean
PM
2.5 [
μg/
m3]
(200
1-20
06)
r
MODIS τ 0.40
MISR τ 0.54
Combined τ 0.63
Combined PM2.5 0.78
van Donkelaar et al., EHP, 2010
Evaluation with measurements outside Canada/US
Global Climatology (2001-2006) of PMGlobal Climatology (2001-2006) of PM2.52.5
Better than in situ vs model (GEOS-Chem): r=0.52-0.62, slope = 0.63 – 0.71
Number sites Correlation Slope Bias (ug/m3)
Including Europe 244 0.86 0.83 1.15
Excluding Europe 84 0.84 0.91 -2.5
van Donkelaar et al., EHP, 2010
van Donkelaar et al., EHP, 2010
van Donkelaar et al., EHP, 2010
• 30% of Asia exposed to >50 μg/m3 in annual mean
• 0.61±0.20 years lost per 10 μg/m3 [Pope et al., 2009]
• Estimate decreased life expectancy due to PM2.5 exposure
PM2.5 Exposure [μg/m3]
Pop
ulat
ion
[%]
Data Valuable to Assess Health Effects of PMData Valuable to Assess Health Effects of PM2.52.5
van Donkelaar et al., EHP, 2010
Simulated (GEOS-Chem) Sulphate TransportSimulated (GEOS-Chem) Sulphate Transport
Aaron van Donkelaar
ChallengesChallenges
Remote Sensing: Improved algorithms to increase accuracy and observe
other pollutants
Modeling: Comprehensive assimilation capability Develop representation of processes
Measurements: Research quality measurements for validation and process-level understanding
Encouraging Prospects for Satellite Remote Encouraging Prospects for Satellite Remote Sensing of Air QualitySensing of Air Quality
Acknowledgements:Acknowledgements: Health Canada Health Canada NSERC NSERC NASA NASA