第一篇
【题目】A synoptic climatological analysis of air quality in the Grand Canyon National Park
【作者】Robert E. Davis and David A. Gay
【链接】http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B757D-48CGB90-P8&_user=1553337&_coverDate=04%2F30%2F1993&_alid=1291628652&_rdoc=1&_fmt=high&_orig=search&_cdi=12896&_sort=r&_docanchor=&view=c&_ct=45316&_acct=C000053666&_version=1&_urlVersion=0&_userid=1553337&md5=46dc592232c8f131017cae7a452c57b3

第二篇
【题目】Air pollution and the decline of the fir forest in Parnis National Park, near Athens, Greece
【作者】 Francis D. Heliotis  Michael G. Karandinos  John C. Whiton
【链接】http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6VB5-48XKNJ3-3H&_user=1553337&_coverDate=12%2F31%2F1988&_alid=1291712770&_rdoc=7&_fmt=high&_orig=search&_cdi=5917&_sort=r&_st=4&_docanchor=&_ct=48&_acct=C000053666&_version=1&_urlVersion=0&_userid=1553337&md5=061ff8712c678ac39c036e9e4f962aac


谢谢~