《Impaired visibility the air pollution people see》.pdf

Atmospheric Environment 43 (2009) 182–195 Contents lists available at ScienceDirect Atmospheric Environment journal homepage: www.else /locate/atmosenv Impaired visibility: the air pollution people see Nicole Pauly Hyslop* Crocker Nuclear Laboratory, University of California, One Shields Avenue, Davis, CA 95616, USA a b s t r a c t Almost every home and office contains a portrayal of a scenic landscape whether on a calendar, postcard, photograph, or painting. The most sought after locations boast a scenic landscape right outside their window. No matter what the scene – mountains, skyscrapers, clouds, or pastureland – clarity and vividness are essential to the image. Air pollution can degrade scenic vistas, and in extreme cases, completely obscure them. Particulate matter suspended in the air is the main cause of visibility degra- dation. Particulate matter affects visibility in multiple ways: obscures distant objects, drains the contrast from a scene, and discolors the sky. Visibility is an environmental quality that is valued for aesthetic reasons that are difficult to express or quantify. Human psychology and physiology are sensitive to visual input. Visibility has been monitored throu