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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 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.
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 satellite
Ozone ●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
A Quick Tutorial…. “Good” Ozone Blocks most UV rays “Bad” Ozone Damages Lungs
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.
Sulfur Dioxide 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
Refineries 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.
PM2.5 Estimation: Popular Methods Difficulty Level Y=mX + c PM2.5 AOT