library(plotly)
EI <- function(TFA,C02) {
  CF=C02/(TFA+45)
  if(CF > 28.3){
  200-(95*log10(CF))
  } else {
  100-(1.34*CF)
  }
}

y_TFA <- 0:150
x_C02 <- 0:10000

matrix=outer(y_TFA,x_C02,FUN=EI)

my_graph=plot_ly(z = matrix, colors = colorRamp(c("red", "green")), type = "heatmap") %>% config(displayModeBar = F)

htmlwidgets::saveWidget(as_widget(my_graph), "epc.html")