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Organic systems are more labor intensive than conventional systems. This higher labor requirement is most often attributed to the increased time monitoring and managing pests. Washington State research statistics indicate that labor hours per acre can be as much as 11% higher for agronomic crops. The increase can be much greater for horticultural crops. Economic Considerations Organic crops can receive price premiums of anywhere from 10% to 200% (or more) over conventionally grown products, according to the USDA Economic Research Service. Although production costs for organic crops can be higher, organic growers typically obtain higher net profits due. | Atmos. Chem. Phys. 10 2353-2376 2010 www.atmos-chem-phys.net 10 2353 2010 Author s 2010. This work is distributed under the Creative Commons Attribution 3.0 License. Atmospheric Chemistry and Physics Chemical evolution of volatile organic compounds in the outflow of the Mexico City Metropolitan area E. C. Apel1 L. K. Emmons1 T. Karl1 F. Flocke1 A. J. Hills1 S. Madronich1 J. Lee-Taylor1 A. Fried1 P. Weibring1 J. Walega1 D. Richter1 X. Tie1 L. Mauldin1 T. Campos1 A. Weinheimer1 D. Knapp1 B. Sive2 L. Kleinman3 S. Springston3 R. Zaveri4 J. Ortega4 P. Voss5 D. Blake6 A. Baker6 C. Warneke7 D. Welsh-Bon7 J. de Gouw7 J. Zheng8 R. Zhang8 J. Rudolph9 W. Junkermann10 and D. D. Riemer11 1National Center for Atmospheric Research Boulder CO USA 2University of New Hampshire Durham NH USA 3Brookhaven National Laboratory Upton NY USA 4Pacific Northwest National Laboratory Richland WA USA 5Smith College and the University of Massachusetts Amherst MA USA 6University of California Irvine CA USA 7National Oceanic and Atmospheric Administration Boulder CO USA 8Department of Atmospheric Sciences Texas A M College Station TX USA 9York University Toronto Ontario Canada 10Institute for Meteorology and Climate Research IMK-IFU Research Center Karlsruhe Garmisch-Partenkirchen Germany 11University of Miami Rosenstiel School of Marine and Atmospheric Sciences Miami FL USA currently at the National Center for Atmospheric Research Boulder CO USA Received 07 October 2009 - Published in Atmos. Chem. Phys. Discuss. 12 November 2009 Revised 12 February 2010 - Accepted 20 February 2010 - Published 8 March 2010 Abstract. The volatile organic compound VOC distribution in the Mexico City Metropolitan Area MCMA and its evolution as it is uplifted and transported out of the MCMA basin was studied during the 2006 MILAGRO MIRAGE-Mex field campaign. The results show that in the morning hours in the city center the VOC distribution is dominated by non-methane hydrocarbons NMHCs but with a substantial .
