There is a deleted scene showing the pull-down window in the Technical Section (where Koenig, Helena and Bergman are enjoying the breeze) being installed. Later, after Bergman informs the Commander that the new atmosphere is corroding their metals, another deleted scene has Koenig ordering that their new windows are to be refitted with the original panes.
Helena reports that the planet's atmosphere contains more than four times the oxygen of Earth's. The Alphans seem a little too anxious to get to the planet, as prolonged exposure to the atmosphere would most likely cause oxygen poisoning.
Filmed July 23rd to August 6th, 1974 (Clifton Jones turning 37 during the shoot). This had been one of the story concepts laid out during the series' pre-production. The scene with the Alphans running around in the rain was filmed out in the studio parking lot on August 21st, during filming of Voyager's Return (1975), the next episode shot.
Victor mentions that with their new atmosphere, fine particles of moon dust have contributed to the atmosphere having a corrosive property. This would be very true; inhaling the moon dust would be particularly harmful. Even without an atmosphere - in the moon's natural state - the dust would cause multiple problems with spacesuits and equipment (as well as inhaling it after entering an airlock; loaded with static electricity, the dust would cling to everything, including spacesuits). Presumably their spacesuits and equipment are hooked up with antistatic devices.
Since the show's second episode, Kano has always been the head of the Computer Department. But in this episode, he's inexplicably the head of the Technical Department, which is why Koenig verbally abuses him over the Eagles having mysteriously fallen into disrepair.