“…T h e phenomenon known as photochemical smog is mainly caused by secondary pollutants (such as oxidants) and is a particularly severe problem in the Los Angeles area, to which reference will frequently be made in the discussion (though findings are not limited in relevance to that one metropolitan area). It happens that until recently,3 more data has been available for Los Angeles than for anywhere else, and, as a result, the EPA chose it as the location for initial testing of the most sophisticated models yet d e~e l o p e d .~ However, other models have been developed and tested in such places as Nashville (Turner, 1964;Miller and Holzworth, 1967), Cincinnati (Clark, 1964), Jacksonville (Koogler et al, 1967), St. Louis (Koch and Thayer, 1972;Ludwig and Dabberdt, 1972;Dabberdt et al, 1973;Shir and Shieh, 1973), Connecticut (Hilst, 1967;Bowne, 1969), Chicago (Roberts et al, 1970), New York (Shieh et al, 1970), San Francisco (MacCracken et al, 1971Ludwig and Kealoha, 1974), and the Hackensack (N J) Meadowland (Wills, 1973).…”