Data frame with components: ozone, radiation, temperature, and wind.
Measurements of daily ozone con- centration (ppb), wind speed (mph),
daily maximum temperature (degrees F), and solar radiation
(langleys) on 111 days from May to September 1973 in New York. This
data frame is similar to air in S-PLUS (or library(data) in S), but
has a different definition for ozone (air contains cube-roots of
ozone).