"<span>Plants and small animals might suffer, and some might die" would be the best option, since the poor air quality would most likely affect certain plants and not others--some of which would be used for food by small animals. </span>
If you're referring to new non-European states that have risen since the Cold War Ended, then the effect has perhaps been minimal in terms of their daily lives, but if they have close relations with the US it would mean a stronger connection.
