ARKHANGELSK, Russia — From the promenade at the water’s edge in the city of Arkhangelsk, a view opens of the broad, fast-flowing Northern Dvina River and a smudge of greenery on the far bank.

About 40 miles in that direction, a still mysterious nuclear accident last week released radiation, killed at least seven people and tripped radiation meters in two cities, including Arkhangelsk.

Yet there they were, Ilya and Yelena Ivanov, pushing a baby stroller on the embankment along with dozens of other new parents, taking in a cool, moist breeze blowing off the water.

“It is worth worrying about,” Yelena said of the radiation release. But the baby, 1-year-old Marina, needed air and besides, she said, nobody had warned against going outside.