Presentation on theme: "Air Quality from Space Bryan N. Duncan Atmospheric Chemistry and Dynamics Laboratory NASA Goddard Space Flight Center Photo from NASA Skylab in 1973 of."— Presentation transcript:
Air Quality from Space 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 = a noxious mixture of particulates & gases Air Quality 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
What are NASA instruments measuring?
●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 Ozone
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 NO x to decrease ozone! Ozone Monitoring Instrument (OMI) on the Aura satellite
Nitrogen dioxide is another precursor to ozone NO 2 is an EPA criteria pollutant as well. Ozone Monitoring Instrument (OMI) on the Aura satellite
Regulations of NO x Emissions are Working! Ozone Monitoring Instrument (OMI) on the Aura satellite NO 2 decreases by 20-50%
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
And for perspective … OMI measurements show that SO 2 was very high in China (2005) and much lower over the Ohio valley in the US. The SO 2 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 OMI SO 2 US Ohio Valley OMI SO 2 China 2005 mean SO2 Column (DU)
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 : increasing power plant emissions Sulfur Dioxide
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 Post Rita = September 27 - October 17 * Pre Katrina = August 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 KatrinaRitaWilma Production [%] Date
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 )?
PM 2.5 Estimation: Popular Methods Two Variable Method Multi-Variable Method Artificial Neural Network MSC AOT PM2.5 Y=mX + c Difficulty Level