\name{environmental}
\alias{environmental}
\docType{data}
\title{ Atmospheric environmental conditions in New York City }

\description{
  Daily measurements of ozone concentration, wind speed, temperature and
  solar radiation in New York City from May to September of 1973.
}

\usage{environmental}

\format{
  A data frame with 111 observations on the following 4 variables.
  \describe{
    \item{ozone}{Average ozone concentration (of hourly measurements) of
      in parts per billion.}
    \item{radiation}{Solar radiation (from 08:00 to 12:00) in langleys.}
    \item{temperature}{Maximum daily emperature in degrees Fahrenheit.}
    \item{wind}{Average wind speed (at 07:00 and 10:00) in miles per hour.}
  }
}

\source{
  Bruntz, S. M., W. S. Cleveland, B. Kleiner, and J. L. Warner.  (1974).
  The Dependence of Ambient Ozone on Solar Radiation, Wind, Temperature,
  and Mixing Height.  In \emph{Symposium on Atmospheric Diffusion and
    Air Pollution}, pages 125--128.  American Meterological Society,
  Boston.
}

\author{
  Documentation contributed by Kevin Wright.
}

\references{
  Cleveland, William S. (1993). \emph{Visualizing Data}.  Hobart Press,
  Summit, New Jersey.
}

\examples{
# Scatter plot matrix with loess lines
splom(~environmental,
  panel=function(x,y){
    panel.xyplot(x,y)
    panel.loess(x,y)
  }
)


# Conditioned plot similar to figure 5.3 from Cleveland
attach(environmental)
Temperature <- equal.count(temperature, 4, 1/2)
Wind <- equal.count(wind, 4, 1/2)
xyplot((ozone^(1/3)) ~ radiation | Temperature * Wind,
  aspect=1,
	prepanel = function(x, y) 
		prepanel.loess(x, y, span = 1),
	panel = function(x, y){
		panel.grid(h = 2, v = 2)
		panel.xyplot(x, y, cex = .5)
		panel.loess(x, y, span = 1)
	},
	xlab = "Solar radiation (langleys)",
	ylab = "Ozone (cube root ppb)")
detach()

# Similar display using the coplot function
with(environmental,{
  coplot((ozone^.33) ~ radiation | temperature * wind,
  number=c(4,4),
  panel = function(x, y, ...) panel.smooth(x, y, span = .8, ...),
  xlab="Solar radiation (langleys)",
  ylab="Ozone (cube root ppb)")
})
}

\keyword{datasets}