The paper examines the interaction among taxes on factors income, environmental quality and welfare. We construct a two-country regional block model with capital mobility and crossborder pollution. Pollution in the two countries is simultaneously abated by the private sector, in response to a pollution tax and by the public sector utilizing income and pollution tax revenue. We demonstrate, among other things, that due to the existence of cross-border pollution in many cases the Nash optimal policy on capital income is a positive tax, even if taxes on the income of immobile factors are chosen optimally. This tax rate increases with the degree of cross-border pollution.