Preface to a Special Issue “Megacity Air Pollution Studies (MAPS)”

Kim, Yong Pyo,Lee, Gangwoong,Emmons, Louisa,Park, Rokjin,Lin, Neng-Huei Taiwan Association for Aerosol Research 2018 Aerosol and air quality research Vol.18 No.9

East Asian tropospheric ozone response to ENSO in CAM-Chem

Yujoo Jeong,Si-Wan Kim,Jeongyeon Kim,Daegeun Shin,Jeongeun Kim,Louisa Emmons,Soon-Il An 한국기상학회 2022 한국기상학회 학술대회 논문집 Vol.2022 No.10

Decoupling peroxyacetyl nitrate from ozone in Chinese outflows observed at Gosan Climate Observatory

Han, Jihyun,Lee, Meehye,Shang, Xiaona,Lee, Gangwoong,Emmons, Louisa K. Copernicus GmbH 2017 Atmospheric Chemistry and Physics Vol.17 No.17

<P>Abstract. We measured peroxyacetyl nitrate (PAN) and other reactive species such as O3, NO2, CO, and SO2 with aerosols including mass, organic carbon (OC), and elemental carbon (EC) in PM2. 5 and K+ in PM1. 0 at Gosan Climate Observatory in Korea (33.17° N, 126.10° E) during 19 October-6 November 2010. PAN was determined through fast gas chromatography with luminol chemiluminescence detection at 425 nm every 2 min. The PAN mixing ratios ranged from 0.1 (detection limit) to 2.4 ppbv with a mean of 0.6 ppbv. For all measurements, PAN was unusually better correlated with PM2. 5 (Pearson correlation coefficient, γ = 0.79) than with O3 (γ = 0.67). In particular, the O3 level was highly elevated with SO2 at midnight, along with a typical midday peak when air was transported rapidly from the Beijing areas. The PAN enhancement was most noticeable during the occurrence of haze under stagnant conditions. In Chinese outflows slowly transported over the Yellow Sea, PAN gradually increased up to 2.4 ppbv at night, in excellent correlation with a concentration increase in PM2. 5 OC and EC, PM2. 5 mass, and PM1. 0 K+. The high K+ concentration and OC ∕ EC ratio indicated that the air mass was impacted by biomass combustion. This study highlights PAN decoupling with O3 in Chinese outflows and suggests PAN as a useful indicator for diagnosing continental outflows and assessing their perturbation of regional air quality in northeast Asia. </P>

EVALUATION OF SATELLITE-BASED MEASUREMENTS FOR TROPOSPHERIC OZONE

Jae H. Kim,Sunmi Na,M. J. Newchurch,L. Emmons 한국기상학회 2002 대기 Vol.12 No.3

Impact of intercontinental pollution transport on North American ozone air pollution: an HTAP phase 2 multi-model study

Huang, Min,Carmichael, Gregory R.,Pierce, R. Bradley,Jo, Duseong S.,Park, Rokjin J.,Flemming, Johannes,Emmons, Louisa K.,Bowman, Kevin W.,Henze, Daven K.,Davila, Yanko,Sudo, Kengo,Jonson, Jan Eiof,Lun European Geophysical Society 2017 Atmospheric chemistry and physics Vol.17 No.9

<P>The recent update on the US National Ambient Air Quality Standards (NAAQS) of the ground-level ozone (O<SUB>3</SUB>/ can benefit from a better understanding of its source contributions in different US regions during recent years. In the Hemispheric Transport of Air Pollution experiment phase 1 (HTAP1), various global models were used to determine the O<SUB>3</SUB> source–receptor (SR) relationships among three continents in the Northern Hemisphere in 2001. In support of the HTAP phase 2 (HTAP2) experiment that studies more recent years and involves higher-resolution global models and regional models’ participation, we conduct a number of regional-scale Sulfur Transport and dEposition Model (STEM) air quality base and sensitivity simulations over North America during May–June 2010. STEM’s top and lateral chemical boundary conditions were downscaled from three global chemical transport models’ (i.e., GEOS-Chem, RAQMS, and ECMWF C-IFS) base and sensitivity simulations in which the East Asian (EAS) anthropogenic emissions were reduced by 20 %. The mean differences between STEM surface O<SUB>3</SUB> sensitivities to the emission changes and its corresponding boundary condition model’s are smaller than those among its boundary condition models, in terms of the regional/period-mean (<10 %) and the spatial distributions. An additional STEM simulation was performed in which the boundary conditions were downscaled from a RAQMS (Realtime Air Quality Modeling System) simulation without EAS anthropogenic emissions. The scalability of O<SUB>3</SUB> sensitivities to the size of the emission perturbation is spatially varying, and the full (i.e., based on a 100% emission reduction) source contribution obtained from linearly scaling the North American mean O<SUB>3</SUB> sensitivities to a 20% reduction in the EAS anthropogenic emissions may be underestimated by at least 10 %. The three boundary condition models’ mean O<SUB>3</SUB> sensitivities to the 20% EAS emission perturbations are ~8% (May–June 2010)/~11% (2010 annual) lower than those estimated by eight global models, and the multi-model ensemble estimates are higher than the HTAP1 reported 2001 conditions. GEOS-Chem sensitivities indicate that the EAS anthropogenic NO<SUB><I>x</I></SUB> emissions matter more than the other EAS O<SUB>3</SUB> precursors to the North American O<SUB>3</SUB>, qualitatively consistent with previous adjoint sensitivity calculations.</P><P>In addition to the analyses on large spatial–temporal scales relative to the HTAP1, we also show results on subcontinental and event scales that are more relevant to the US air quality management. The EAS pollution impacts are weaker during observed O<SUB>3</SUB> exceedances than on all days in most US regions except over some high-terrain western US rural/remote areas. Satellite O<SUB>3</SUB> (TES, JPL–IASI, and AIRS) and carbon monoxide (TES and AIRS) products, along with surface measurements and model calculations, show that during certain episodes stratospheric O<SUB>3</SUB> intrusions and the transported EAS pollution influenced O<SUB>3</SUB> in the western and the eastern US differently. Free-running (i.e., without chemical data assimilation) global models underpredicted the transported background O<SUB>3</SUB> during these episodes, posing difficulties for STEM to accurately simulate the surface O<SUB>3</SUB> and its source contribution. Although we effectively improved the modeled O<SUB>3</SUB> by incorporating satellite O<SUB>3</SUB> (OMI and MLS) and evaluated the quality of the HTAP2 emission inventory with the Royal Netherlands Meteorological Institute–Ozone Monitoring Instrument (KNMI–OMI) nitrogen dioxide, using observations to evaluate and improve O<SUB>3</SUB> source attribution still remains to be further explored.</P>

HTAP2 multi-model estimates of premature human mortality due to intercontinental transport of air pollution and emission sectors

Liang, Ciao-Kai,West, J. Jason,Silva, Raquel A.,Bian, Huisheng,Chin, Mian,Davila, Yanko,Dentener, Frank J.,Emmons, Louisa,Flemming, Johannes,Folberth, Gerd,Henze, Daven,Im, Ulas,Jonson, Jan Eiof,Keati Copernicus GmbH 2018 Atmospheric Chemistry and Physics Vol.18 No.14

<P><p><strong>Abstract.</strong> Ambient air pollution from ozone and fine particulate matter is associated with premature mortality. As emissions from one continent influence air quality over others, changes in emissions can also influence human health on other continents. We estimate global air-pollution-related premature mortality from exposure to PM<span class='inline-formula'>_2.5</span> and ozone and the avoided deaths due to 20<span class='thinspace'></span>% anthropogenic emission reductions from six source regions, North America (NAM), Europe (EUR), South Asia (SAS), East Asia (EAS), Russia-Belarus-Ukraine (RBU), and the Middle East (MDE), three global emission sectors, power and industry (PIN), ground transportation (TRN), and residential (RES), and one global domain (GLO), using an ensemble of global chemical transport model simulations coordinated by the second phase of the Task Force on Hemispheric Transport of Air Pollutants (TF HTAP2), and epidemiologically derived<span id='page10498'/> concentration response functions. We build on results from previous studies of TF HTAP by using improved atmospheric models driven by new estimates of 2010 anthropogenic emissions (excluding methane), with more source and receptor regions, new consideration of source sector impacts, and new epidemiological mortality functions. We estimate 290<span class='thinspace'></span>000 (95<span class='thinspace'></span>% confidence interval (CI): 30<span class='thinspace'></span>000, 600<span class='thinspace'></span>000) premature <span class='inline-formula'>O₃</span>-related deaths and 2.8 million (0.5 million, 4.6 million) PM<span class='inline-formula'>_2.5</span>-related premature deaths globally for the baseline year 2010. While 20<span class='thinspace'></span>% emission reductions from one region generally lead to more avoided deaths within the source region than outside, reducing emissions from MDE and RBU can avoid more <span class='inline-formula'>O₃</span>-related deaths outside of these regions than within, and reducing MDE emissions also avoids more PM<span class='inline-formula'>_2.5</span>-related deaths outside of MDE than within. Our findings that most avoided <span class='inline-formula'>O₃</span>-related deaths from emission reductions in NAM and EUR occur outside of those regions contrast with those of previous studies, while estimates of PM<span class='inline-formula'>_2.5</span>-related deaths from NAM, EUR, SAS, and EAS emission reductions agree well. In addition, EUR, MDE, and RBU have more avoided <span class='inline-formula'>O₃</span>-related deaths from reducing foreign emissions than from domestic reductions. For six regional emission reductions, the total avoided extra-regional mortality is estimated as 6000 (<span class='inline-formula'>−</span>3400, 15<span class='thinspace'></span>500) deaths per year and 25<span class='thinspace'></span>100 (8200, 35<span class='thinspace'></span>800) deaths per year through changes in <span class='inline-formula'>O₃</span> and PM<span class='inline-formula'>_2.5</span>, respectively. Interregional transport of air pollutants leads to more deaths through changes in PM<span class='inline-formula'>_2.5</span> than in <span class='inline-formula'>O₃</span>, even though <span class='inline-formula'>O₃</span> is transported more on interregional scales, since PM<span class='inline-formula'>_2.5</span> has a stronger influence on mortality. For NAM and EUR, our estimates of avoided mortality from regional and extra-regional emission reductions are comparable to those estimated by regional models for these same experiments. In sectoral emission reductions, TRN emissions account for the greatest fraction (26-53<span class='thinspace'></span>% of global emission reduction) of <span class='inline-formula'>O₃</span>-rela

Nontransformational Syntax

Bach, Emmon 서울대학교 어학연구소 1981 語學硏究 Vol.17 No.1

Last year at the University of Wisconsin in Milwaukee there was a conference about the theory of syntax. Fourteen different theories of syntax wre discussed at this conference. The aim of the conference was to see if there could be some measure of agreement about syntactic theory. I did not attend the conference but I am told that at the end of the conference there were still fourteen theories of syntax, maybe even more. I like to look behind disagreements about details and notice agreements that were sometimes apparent in the heat of discussions and battle. I don't know about Korean linguists but in America linguists love to argue, and it is very hard for many linguists to say, "Yes", when someone says, "Well, you really agree with me, don't you?" Then they usually say, "No." There is a story about Noam Chomsky, who, I think, is perhaps most argumentative of all. He was giving a lecture at a university in Canada and someone in the audience got up and said, "Well, I agree with you because of this and this...," and Noam Chomsky immediately said, "No, you don't."