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Emerging issues in air quality

Emerging issues in air quality. Daniel J. Jacob. w ith Lin Zhang, Raluca Ellis, Fabien Paulot , Eloise Marais, Qiaoqiao Wang, Kevin Wecht , Alex Turner, Helen Amos, Hannah Horowitz. and Anne Perring , Joshua Schwartz, David Fahey (NOAA),

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Emerging issues in air quality

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  1. Emerging issues in air quality Daniel J. Jacob with Lin Zhang, Raluca Ellis, Fabien Paulot, Eloise Marais, Qiaoqiao Wang, Kevin Wecht, Alex Turner, Helen Amos, Hannah Horowitz and Anne Perring, Joshua Schwartz, David Fahey (NOAA), Cui Ge, Jun Wang (U. Nebraska), David Streets (Argonne) Support from BP, NASA, NSF

  2. 4th-highest annual maximum of daily 8-h average ozone,2008-2010 Current standard: 75 ppb Proposed standard: 60-70 ppb

  3. Long-term surface ozone trend Trend in 95th percentile, June-August 1990-2010 • Decrease in eastern US driven by NOx emission controls; • Increase or flat in Intermountain West Cooper et al. [2012]

  4. 4th-highest annual maximum for daily 8-h average ozone,2008-2010 Intermountain West: The next ozone frontier! High elevation, arid terrain → high ozone background Current standard: 75 ppb Proposed standard: 60-70 ppb

  5. High background and stratospheric intrusionsin Intermountain West Two definitions of stratospheric influence on tropospheric ozone: Ozone at Gothic, Colorado (2,900m) Observed GEOS-Chem N Am background O3 produced in stratosphere O3 transported from stratosphere S T tropopause Strat (transported) Strat (produced) 2007 • Most surface ozone in Intermountain West originates from outside N America • Highest ozone events (>80 ppb) due to stratospheric filaments, • cannot be reproduced in models (stretched-flow numerical diffusion) • Have to be careful with definition of stratospheric influence Zhang et al., in prep.

  6. Wildfire plumes alone do not drive high-ozone events Glacier NP, 2007: model has high O3 in fire plumes, observations show none Organic aerosol (OC) correlates with western US fires but not ozone OC (IMPROVE) Ozone (CASTNet) 2006-2008 Observed GEOS-Chemwildfires • No evidence of high-ozone events from fire plumes unless mixed with pollution • Models generate excessive ozone because they don’t account for emissions of highly reactive VOCs that lock up NOx as PAN in the plume – a difficult problem! • Fires can still contribute to background ozone through PAN decomposition Zhang et al., in prep.

  7. N deposition at US national parks: critical load exceedances Critical loads are 3-5 kg N ha-1 a-1 depending on ecosystem More deposition is expected to originate from ammonia in future Present and future (RCP) US emissions 2006 NOx NH3 2050 2006 Future exceedances driven by ammonia emissions 2050 RCP2.6 Ellis et al. [2013] Ellis et al. [submitted]

  8. Optimizing NH3 emissions by adjoint inversion of 2005-2008 NH4+ wet deposition flux data NADP data (circles) and GEOS-Chem model after adjoint inversion April: fertilizer July: livestock kgN ha-1 month-1 Error correlation between NH4+ wet deposition flux (F) and precipitation (P) obtained by GEOS-Chem simulations with GEOS-4 vs. GEOS-5 meteorology: 0.6 power dependence FGEOS5/FGEOS4 PGEOS5/PGEOS4 Paulot et al. [submitted]

  9. Optimized ammonia emissions …and new MASAGE bottom-up ammonia emission inventory US EU E Asia x 0.5 8.4 (China) 2.8 3.1 8.4 2.7 2.9 natural crops other anthro livestock Paulot et al. [submitted]

  10. N deposition from agriculture is a global pollution problem Annual mean agricultural ammonia emissions from MASAGE (2005-2008) 63% are from countries outside the US, European Union, and China Paulot et al. [submitted]

  11. MASAGE NH3 emissions from food export Contribution of US food export to PM (NH4NO3) air pollution PM due to food export (GEOS-Chem) wheat corn beef annual Economic implications by state ($ per capita): Paulot et al., in prep

  12. OMI formaldehyde 2005-2009 Next frontier for air pollution: Nigeria • Population: 270 million (+2.6% a-1) • GDP: $273 billion (+7% a-1) – oil! • Most natural gas is flared • >80% of domestic energy from biofuel, waste gas flaring! An unusual mix of very high VOCs, low NOx – What will happen as infrastructure develops? 1015 molecules cm-2 aerosol (AOD) NO2 HCHO glyoxal methane Lagos Port Harcourt SCIA MISR Marais et al., in prep.

  13. Multimodel intercomparison and comparison to observations Multimodel intercomparisons and comparisons to observations Large model errors for black carbon (BC) aerosol in remote air Ensemble of AeroCom models ARCTAS (Arctic spring) TC4 (Costa Rica, summer) Observed Models Pressure, hPa BC, ng kg-1 BC, ng kg-1 HIPPO over Pacific (Jan) • Models differ by order of magnitude between themselves and with observations • Large overestimates of observations over oceans, • upper troposphere • Discrepancy must be driven by model errors in scavenging Pressure, hPa obs models 20S-20N obs models 60-80N BC, ng kg-1 BC, ng kg-1 Koch et al. [2009], Schwarz et al. [2010]

  14. Global BC simulation in GEOS-Chem Source (2009): 4.9 Tg a-1 fuel + 1.6 Tg a-1 open fires Lifetime: 4.2 days Successful simulation in source regions and outflow Observations (circles) and model (background) Wang et al., in prep NMB= -27% surface networks AERONET BC AAOD NMB= 6.6% NMB= -32% Aircraft profiles in continental/outflow regions HIPPO (US) Asian outflow (A-FORCR) US (HIPPO) observed model Arctic (ARCTAS) NMB= -12%

  15. Observations by Perring et al. (in prep.) HIPPO BC curtains across the Central Pacific, 2009-2011 PDF Observed Model PDF, (mg m-3 STP)-1 • Minima in deep tropics • Model doesn’t capture low tail, is also too high at N mid-latitudes; median bias is factor of 2, mean column bias is +48% Wang et al., in prep

  16. BC top-of-atmosphere direct radiative forcing (DRF) • In our work, BC above 5 km contributes 30% of global DRF and BC over the oceans contributes 24%; these contributions would be higher in other models with less efficient scavenging. • We find that BC radiative forcing is much less than previously estimated; • need to better understand BC in free/remote troposphere! Wang et al., in prep

  17. Constraints on US methane emissions from SCIAMACHY data • Adjoint inversion with EDGAR v4.2 (anthropogenic), Kaplan (wetlands) as priors • Focus on INTEX-A mission period to validate SCIAMACHY data and inversion SCIA CH4 column mixing ratio, Jul-Aug 2004 Adjoint inversion scaling factors ppb 1700 1800 Total US anthropogenic emissions (Tg a-1) EDGAR v4.2 26.6 EPA 28.3 This work 32.7 1.0 0.5 1.5 Wecht et al. [in prep]

  18. Methane from GOSAT: preliminary adjoint inversion Can we monitor from space the evolving source from oil & gas? GOSAT data for CalNex period (May-Jul 10) Scaling factors to EDGAR inventory • GOSAT data show consistency with SCIAMACHY for constraining livestock and wetland sources, but also discrepancies • The data are sparse; now applying a Gaussian Mixture Model to optimally reduce the state vector for the inversion Turner et al. [in progress]

  19. Biogeochemical cycle of mercury ANTHROPOGENIC PERTURBATION: fuel combustion mining WATER-SOLUBLE VOLATILE oxidation Hg(II) Hg(0) lifetime ~6 months (months) volcanoes erosion ATMOSPHERE OCEAN/SOIL Hg(0) Hg(II) particulate Hg reduction biological uptake burial uplift SEDIMENTS

  20. History of global anthropogenic Hg emissions Large past (legacy) contribution from N. American and European emissions; Asian dominance is a recent phenomenon Streets et al. , 2011

  21. Global source contributions to Hg in present-day surface ocean from biogeochemical box model constrained with GEOS-Chemfluxes emissions pre-1850 natural • Human activity has increased 7x the Hg content of the surface ocean • Half of this human influence is from pre-1950 emissions • N America, Europe and Asia share similar responsibilities for anthropogenic Hg in present-day surface ocean ROW former USSR N America S America Europe Asia Amos et al., in press

  22. Disposal of Hg in commercial products:a missing component of the Hg biogeochemical cycle? Global production of commercial Hg peaked in 1970 • Commercial Hg enters environment upon use or disposal; much larger source than inadvertent emission • Could explain observed atmospheric decrease of Hg(0) over past two decades Environmental release from commercial products dwarfs current emission estimates Horowitz et al., in prep

  23. selected in November 2012 for 2018/2019 launch PI: Kelly Chance, Harvard-Smithsonian • Monitoring of tropospheric ozone (2 levels), aerosols, NO2, SO2, formaldehyde, glyoxal with 1-hour temporal resolution, 4-km spatial resoution • To be part of a geostationary constellation with other sensors observing Europe and East Asia TEMPO geostationary UV/Vis satellite instrument Next frontier in satellite observations of atmospheric composition! TEMPO Sentinel-4 GEMS

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