Suppose you mapped the locations of individual gas wells, looked at the distance between the wells and the homes where the mothers of those babies lived during their pregnancies. (dotearth.blogs.nytimes.com)
$ 17,000 later I had 3 individual electric meters and 3 individual gas meters. (thegreenswan.org)
The changes in the atmospheric abundance of individual gases are shown in the lower panels using a combination of direct atmospheric measurements, estimates of historical abundance, and future projections of abundance. (esrl.noaa.gov)