Reply to comment by KentDarkmere in TIL the first Blue LED wasn't commercially available until 1989 and bright blue LEDs weren't available until 1993. by j-merc23

Reply to comment by [deleted] in 30 minutes of car preheating in sub-zero conditions produces as much particulate emissions as driving 97km in a gasoline car, or 20km in a diesel car “These findings do not suggest to stop preheating cars; instead, we could reduce the emissions by using similar methods that are in place for engine” by giuliomagnifico