<?xml version="1.0" encoding="UTF-8"?><xml><records><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Guo, S.</style></author><author><style face="normal" font="default" size="100%">Hu, M.</style></author><author><style face="normal" font="default" size="100%">Zamora, M. L.</style></author><author><style face="normal" font="default" size="100%">Peng, J. F.</style></author><author><style face="normal" font="default" size="100%">Shang, D. J.</style></author><author><style face="normal" font="default" size="100%">Zheng, J.</style></author><author><style face="normal" font="default" size="100%">Du, Z. F.</style></author><author><style face="normal" font="default" size="100%">Wu, Z.</style></author><author><style face="normal" font="default" size="100%">Shao, M.</style></author><author><style face="normal" font="default" size="100%">L.M. Zeng</style></author><author><style face="normal" font="default" size="100%">Molina, M. J.</style></author><author><style face="normal" font="default" size="100%">Zhang, R. Y.</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Elucidating severe urban haze formation in China</style></title><secondary-title><style face="normal" font="default" size="100%">Proceedings of the National Academy of Sciences of the United States of AmericaProceedings of the National Academy of Sciences of the United States of AmericaProceedings of the National Academy of Sciences of the United States of America</style></secondary-title><alt-title><style face="normal" font="default" size="100%">P Natl Acad Sci USA</style></alt-title><short-title><style face="normal" font="default" size="100%">P Natl Acad Sci USAP Natl Acad Sci USA</style></short-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">aerosol mass-spectrometry</style></keyword><keyword><style  face="normal" font="default" size="100%">China</style></keyword><keyword><style  face="normal" font="default" size="100%">city</style></keyword><keyword><style  face="normal" font="default" size="100%">january 2013</style></keyword><keyword><style  face="normal" font="default" size="100%">nucleation</style></keyword><keyword><style  face="normal" font="default" size="100%">oh-initiated reactions</style></keyword><keyword><style  face="normal" font="default" size="100%">particle formation</style></keyword><keyword><style  face="normal" font="default" size="100%">pm2.5</style></keyword><keyword><style  face="normal" font="default" size="100%">pollution</style></keyword><keyword><style  face="normal" font="default" size="100%">secondary aerosols</style></keyword><keyword><style  face="normal" font="default" size="100%">source apportionment</style></keyword><keyword><style  face="normal" font="default" size="100%">sulfuric-acid</style></keyword><keyword><style  face="normal" font="default" size="100%">supersite t0</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2014</style></year><pub-dates><date><style  face="normal" font="default" size="100%">Dec 9</style></date></pub-dates></dates><number><style face="normal" font="default" size="100%">49</style></number><volume><style face="normal" font="default" size="100%">111</style></volume><pages><style face="normal" font="default" size="100%">17373-17378</style></pages><isbn><style face="normal" font="default" size="100%">0027-8424</style></isbn><language><style face="normal" font="default" size="100%">English</style></language><abstract><style face="normal" font="default" size="100%">As the world's second largest economy, China has experienced severe haze pollution, with fine particulate matter ( PM) recently reaching unprecedentedly high levels across many cities, and an understanding of the PM formation mechanism is critical in the development of efficient mediation policies to minimize its regional to global impacts. We demonstrate a periodic cycle of PM episodes in Beijing that is governed by meteorological conditions and characterized by two distinct aerosol formation processes of nucleation and growth, but with a small contribution from primary emissions and regional transport of particles. Nucleation consistently precedes a polluted period, producing a high number concentration of nano-sized particles under clean conditions. Accumulation of the particle mass concentration exceeding several hundred micrograms per cubic meter is accompanied by a continuous size growth from the nucleation-mode particles over multiple days to yield numerous larger particles, distinctive from the aerosol formation typically observed in other regions worldwide. The particle compositions in Beijing, on the other hand, exhibit a similarity to those commonly measured in many global areas, consistent with the chemical constituents dominated by secondary aerosol formation. Our results highlight that regulatory controls of gaseous emissions for volatile organic compounds and nitrogen oxides from local transportation and sulfur dioxide from regional industrial sources represent the key steps to reduce the urban PM level in China.</style></abstract><accession-num><style face="normal" font="default" size="100%">WOS:000345921500021</style></accession-num><notes><style face="normal" font="default" size="100%">Au9nrTimes Cited:8Cited References Count:46</style></notes><auth-address><style face="normal" font="default" size="100%">Hu, MPeking Univ, Coll Environm Sci &amp; Engn, State Key Joint Lab Environm Simulat &amp; Pollut Con, Beijing 100871, Peoples R ChinaPeking Univ, Coll Environm Sci &amp; Engn, State Key Joint Lab Environm Simulat &amp; Pollut Con, Beijing 100871, Peoples R ChinaPeking Univ, Coll Environm Sci &amp; Engn, State Key Joint Lab Environm Simulat &amp; Pollut Con, Beijing 100871, Peoples R ChinaTexas A&amp;M Univ, Ctr Atmospher Chem &amp; Environm, Dept Atmospher Sci, College Stn, TX 77843 USATexas A&amp;M Univ, Ctr Atmospher Chem &amp; Environm, Dept Chem, College Stn, TX 77843 USAUniv Calif San Diego, Dept Chem &amp; Biochem, La Jolla, CA 92093 USA</style></auth-address></record></records></xml>