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Air Quality from Space. Photo from NASA Skylab in 1973 of Los Angeles smog. Satellites provide a “birds eye” view. Bryan N. Duncan Atmospheric Chemistry and Dynamics Laboratory NASA Goddard Space Flight Center. Air Quality. Smog = a noxious mixture of particulates & gases.
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Air Quality from Space
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Air Quality from Space
Photo from NASA Skylab in 1973 of Los Angeles smog.
Satellites provide a “birds eye” view.
Bryan N. Duncan
Atmospheric Chemistry and Dynamics Laboratory
NASA Goddard Space Flight Center
Air Quality
Smog = a noxious mixture of particulates & gases
In the US, 120 million people currently live in areas that do not meet air quality standards
Where there are lights, there is pollution!
Visible Infrared Imaging Radiometer Suite (VIIRS)
on the Suomi NPP satellite
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.
Pollution has a global impact via long-range transport!
True Color Image from the Moderate Resolution Imaging Spectroradiometer (MODIS) on the Terra satellite
●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
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 NOx to decrease ozone!
Ozone Monitoring Instrument (OMI) on the Aura satellite
Nitrogen dioxide is another precursor to ozone
Ozone Monitoring Instrument (OMI) on the Aura satellite
NO2 is an EPA criteria pollutant as well.
Regulations of NOx Emissions are Working!
NO2 decreases by 20-50%
2010
2005
Ozone Monitoring Instrument (OMI) on the Aura satellite
SO2 Reductions over the Eastern US as Seen by OMI
When combusted, coal with sulfur impurities leads to the formation of SO2 – a precursor to acid rain and PM2.5.
2008-2010
2005-2007
Ozone Monitoring Instrument (OMI) on the Aura satellite
And for perspective …
OMI SO2 China 2005 mean
OMI SO2 US Ohio Valley
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)
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.
2005-2007: increasing power plant emissions
2005
2006
2007
Chinese SO2 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.
2008
2008: Beijing Olympics, stringent emission control measures were enforced
2009
2009: Global economic crisis, reduce industrial activity and strict emission controls continue
Landfall
Aug. 29th
New Orleans
Katrina
LA Offshore Oil Port reopened Nov. 5th
Rita
Landfall
Sep. 24th
The Impact of the 2005 Gulf Hurricanes on NO2
Destroyed Oil Platforms (, )
Difference in OMI NO2
(Pre Katrina - Post Rita *)
x1015molec/cm2
Reductions in Oil & Gas Production
* Pre Katrina = August 1 - 26
Post Rita = September 27 - October 17
Katrina
Rita
Wilma
Production [%]
Hurricanes Katrina and Rita caused a significant reduction in NO2 emissions from oil and gas production facilities as well as power plants.
Date
Wildfires & Agricultural Fires
Cold Front
Agricultural Fires
But how does satellite AOD (unitless) relate to “nose-level” PM2.5 (ug/m3)?
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.
