Bryan N Duncan Atmospheric Chemistry and Dynamics Laboratory NASA Goddard Space Flight Center Photo from NASA Skylab in 1973 of Los Angeles smog Satellites provide a birds eye view Smog ID: 501917
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Slide1
Air Quality from Space
Bryan N. DuncanAtmospheric Chemistry and Dynamics LaboratoryNASA Goddard Space Flight Center
Photo from NASA Skylab in 1973 of Los Angeles smog.
Satellites provide a “birds eye” view.Slide2
Smog =
a noxious mixture of particulates & gases
Air Quality
In the US, 120 million people currently live in areas that do not meet air quality standardsSlide3
Where there are lights, there is pollution!
Visible Infrared Imaging Radiometer Suite (VIIRS
)o
n the Suomi NPP satelliteSlide4
Question:
Why does NASA monitor pollution? Isn’t that the job of the EPA?
Answer: Spatial coverage.
Instruments on NASA satellites can measure pollution over the whole U.S. and even the whole globe. Surface measurements are sparse and don’t give us the whole air pollution picture.Slide5
Haze over the Mid-Atlantic
Pollution has a global impact via long-range transport!
True Color Image from the Moderate
Resolution Imaging Spectroradiometer (MODIS) on the Terra satelliteSlide6
What are
NASA
instruments
measuring?Slide7
●The ozone standard is currently 75 ppbv as averaged over 8-hours.
● A new rule may lower the standard to 60 ppbv = European standard.
Source of graphic:Wall Street Journal, July 21, 2011
OzoneSlide8
A Quick Tutorial….
“Good” Ozone
Blocks most UV rays
“Bad” OzoneDamages LungsSlide9
Formaldehyde – a proxy for VOCs – a precursor to ozone
Isoprene is a VOC emitted from trees & emissions
increase with temperature.HCHO is a product of isoprene oxidation,
so variation in the concentration of HCHO can serve as a proxy for variation of isoprene.Isoprene plays an important role in the formation of unhealthy levels of ozone – more important than anthropogenic VOCs, so
must decrease NO
x
to decrease ozone!
Ozone Monitoring Instrument (OMI) on the Aura satelliteSlide10
Nitrogen
dioxide is another precursor to ozone
NO
2
is an EPA criteria
pollutant as well.
Ozone Monitoring Instrument (OMI) on the Aura satelliteSlide11
11
2005
2010
Regulations of NO
x
Emissions are Working!
Ozone Monitoring Instrument (OMI) on the Aura satellite
NO
2
decreases by 20-50%Slide12
SO
2 Reductions over the Eastern US as Seen by OMI
Ozone Monitoring Instrument (OMI) on the Aura satellite
When combusted, coal with sulfur impurities leads to the formation of SO
2
– a precursor to acid rain and PM
2.5
.
2005-2007
2008-2010Slide13
And for perspective …
OMI measurements show that SO2
was very high in China (2005) and much lower over the Ohio valley in the US. The SO2
in China comes from power plants without scrubbers burning high sulfur coal. The 1971 Clean Air Act mandated scrubbers on US power plants built after 1977.
OMI SO
2
US Ohio Valley
OMI SO
2
China 2005 mean
0.0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5
SO2 Column (DU) Slide14
2008: Beijing Olympics, stringent emission control measures were enforced
Chinese SO
2
emission controls were strengthened by the 11th Five-Year-Plan that requires flue-gas desulfurization technology (FGD) on all new plants and some old ones. There is also better inspection and enforcement.
2009: Global economic crisis, reduce industrial activity and strict emission controls continue
2005-2007: increasing power plant emissions
Sulfur Dioxide
2005
2006
2007
2008
2009Slide15
The Impact of the 2005 Gulf Hurricanes
on NO
2
Difference in OMI NO
2
(Pre Katrina - Post Rita *)
x10
15
molec
/cm
2
Reductions in Oil & Gas Production
Destroyed Oil Platforms (
,
)
*
Pre Katrina = August 1 - 26
Post Rita = September 27 - October 17
Hurricanes Katrina and Rita caused a significant reduction in NO
2
emissions from oil and gas production facilities as well as power plants.
Katrina
Refineries
New Orleans
LA Offshore Oil Port reopened Nov. 5
th
Rita
Landfall
Sep. 24
th
Landfall
Aug. 29
th
Katrina
Rita
Wilma
Production [%]
DateSlide16
Wildfires & Agricultural Fires
Cold Front
Agricultural Fires
AOD
= Aerosol Optical Depth
the
degree to which aerosols prevent the transmission of light by absorption or scattering of light through the entire vertical column of the atmosphere from the ground to the satellite’s
sensor.
But how does satellite AOD (
unitless
) relate to “nose-level” PM
2.5
(
ug
/m
3
)?Slide17
PM
2.5 Estimation: Popular Methods
AOT
PM2.5
Y=mX + c
Difficulty LevelSlide18
Satellite-Derived PM
2.5 [ug/m3
]
18