As long as a market economy is in place, Albert and Hahnel favour Pigovian taxes over other solutions to environmental problems such as command and control, or the issuance of marketable permits. However, Hahnel, who teaches ecological economics at American University, argues that in a market economy businesses try to avoid the "polluter pays principle" by shifting the burden of the costs for their polluting activities to consumers. In terms of incentives, he argues this might be considered a positive development because it would penalize consumers for "dirty" consumption. However, it also has regressive implications since tax incidence studies show that ultimately it would be poor people who would bear a great deal of the burden of many pollution taxes. "In other words, many pollution taxes would be highly regressive and therefore aggravate economic injustice." He, therefore, recommends that pollution taxes be linked to cuts in regressive taxes such as social security taxes.