adversely
adv.in a way that is negative or harmful. You use this when something has a bad effect on a situation or person.
adv.in a manner that is harmful, negative, or contrary to one's interests. Often used to describe how external factors impact a system, health, or financial status.
“The cold weather affected the crops adversely.”
“The new tax laws will adversely affect small businesses that rely on international shipping.”
“Economists worry that the sudden increase in interest rates will adversely impact consumer spending, potentially leading to a period of stagnant growth across the retail sector.”
Typically placed before the verb it modifies or at the end of the clause.
Adversely is an adverb modifying the verb 'affect', which is transitive and does not take the preposition 'to'.
Usage adversely affect
From adverse + -ly.
Etymology adapted from Wiktionary, available under CC BY-SA 4.0.