HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Abstract Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via ISI Web of Science (3) Citing Articles via Google Scholar Google Scholar Articles by Schade, G. W. Articles by Goldstein, A. H. Search for Related Content PubMed PubMed Citation Articles by Schade, G. W. Articles by Goldstein, A. H. GeoRef GeoRef Citation Agricola Articles by Schade, G. W. Articles by Goldstein, A. H. Related Collections Organic Compounds Air Pollution

Atmospheric Methyl Tertiary Butyl Ether (MTBE) at a Rural Mountain Site in California

University of California at Berkeley, Dep. of Environmental Science, Policy, and Management (ESPM), Ecosystem Science Division, 151 Hilgard Hall, Berkeley, CA 94720-3110

View larger version (23K): [in a new window]   Fig. 1. County map of northern California showing the site as well as some major cities from which advection of anthropogenic hydrocarbons can occur. Also shown are two 12-h isentropic back-trajectories calculated with HYSPLIT (National Oceanic and Atmospheric Administration Air Resources Laboratory, 1997) for 18 and 21 June 1999, arriving at Blodgett at 1900 h (first symbol at -1 h).

View larger version (24K): [in a new window]   Fig. 2. Methyl tertiary butyl ether (MTBE) mixing ratio distributions (quantification for 1997 is tentative) near Blodgett Forest Research Station. The dashed line represents the detection limit.

View larger version (43K): [in a new window]   Fig. 3. Mixing ratios of isopentane and methyl tertiary butyl ether (MTBE) during 17–21 June 1999, along with the wind speed (thin line, multiplied by 10) and direction (thick line) (see also Fig. 1).

View larger version (27K): [in a new window]   Fig. 4. (a) Median diurnal mixing ratio variation of methyl tertiary butyl ether (MTBE), isopentane, and n-pentane above their regional background levels (see legend), together with the median wind direction pattern for 17–20 June 1999 (thick line). (b) Median diurnal change of the isopentane to MTBE ratio for that time, including the background ratio (dotted line).

View larger version (28K): [in a new window]   Fig. 5. Example of three-day back trajectories from 24 Oct. 1998 and 30 Aug. to 1 Sept. 1999 during which methyl tertiary butyl ether (MTBE) at Blodgett Forest (Blo) was at or below the detection limit, while toluene was still detectable. SF and Sac indicate the longitude of the urban centers Sacramento (Central Valley) and San Francisco (west coast). Three additional trajectories from June 1999 with "normal" flow through the Central Valley are depicted as well.

View larger version (37K): [in a new window]   Fig. 6. Dependence of the methyl tertiary butyl ether (MTBE) to toluene ratio on MTBE abundance for fall 1998 and summer 1999. The horizontal gray bar depicts the estimated emission ratio from the Caldecott tunnel experiments (Kirchstetter et al., 1999), the dotted line is a calculated, background-corrected ratio at Blodgett Forest assuming source emission ratio (ERsource) = 0.5, [OH] = 1.1 x 107 molecules cm-3, and t = 9 h.