A negative externality exists when exceed The net effect of a negative externality decreases O only consumer surplus. O only producer surplus. O the deadweight loss. O both producer and consumer surpluses. about us Careers privacy policy Terms of use contact us ée 9 A negative externality exists when exceed social costs social benefits The net effect of a negative external private costs private benefits private costs social costs O only consumer surplus. social benefits O only producer surplus. private benefits O the deadweight loss. O both producer and consumer surpluses. erms of contact us privacy policy T about us careers on ее по