Formaldehyde was measured in rainwater samples collected at a residential a
rea of Trombay, Mumbai (a coastal site in India). A mean concentration of 2
.1 mu mol/l and a range of 0.4-11.0 mu mol/l were observed. The mean formal
dehyde concentration in rainwater has increased from 1.2 mu mol/l in 1979 b
y a factor of about two at this site.