Assuming your data is in datf ...
First, I would choose exactly what you need in order to make the right choice.
datf <- datf[order(datf$pollut, datf$lag), ]
You need space before and after each lab grouping, so I would add extra lines that have NA. This makes the job easier, because then you will automatically have gaps in your conversations.
datfPlusNA <- lapply(split(datf, datf$pollut), function(x) rbind(NA, x, NA)) datf <- do.call(rbind, datfPlusNA)
Now that you have the data.frame sorted and with additional NAs, drawing is simple.
nr <- nrow(datf)
There are packages that make this easier, but if you can do it, you can start making any graphics you can imagine.

source share