Any animal that inhaled the toxic air would grow larger and go into a frantic state. No one cared about those wild animals in a chaotic time like this though.
Various countries kept cubs and genes of wild animals. Heatia was a poor country, and only 10% of its population got into the arks. The other 90% were left to die.
The frantic beasts charged into cities and hunted the people by following their scents.
Humans also went berserk when they inhaled the toxic substance and began to attack animals and other humans.
All hell broke loose in Heatia.
Heatia was close to the equator and wasn't affected by tsunamis or earthquakes. There were no volcanoes on its land either. It had never occurred to them that they would escape the natural disasters only to die in the hands of their own people.