防治污染政策與研發補貼：R&D 內生成長模型的應用

Environmental Protection Policy and the R&D Subsidy: Application of R&D Endogenous Growth Model

本文乃將R&D 內生成長模型中，考量中間財為獨占性競爭且具有污染性之產業，據此探討若政府對中間財部門課徵污染稅，並專款專用來從事防治污染支出，而對R&D 部門之研發活動予以補貼，分別分析此兩種政策對於經濟成長與社會福利會產生何種影響？透過比較靜態與數值模擬分析的結果顯示，政府對中間財部門的污染課稅，除了可以改善環境品質外，經濟體系亦分別存在一個「成長率極大之最適污染稅率」與「福利極大之最適污染稅率」，使得經濟成長率與社會福利分別達到極大。而對R&D 部門補貼則有助於經濟成長，同時亦存在一個最適的R&D部門補貼率，使得社會福利達到極大。

This paper integrates the R&D-based model with environmentalprotection, and sets the intermediate goods sectors as monopolisticallycompetitive and as polluting industries. The government sector has twopolicies. One policy is to tax polluters, the intermediate goods sectors, fortheir pollution inputs to finance pollution prevention. The other policy is toimpose a lump-sum tax on households to partially finance the subsidyexpenditure for the R&D sector. This paper discusses how the twopolicies affect the economic growth rate and welfare. By comparativestaticand numerical simulation analysis, we find that taxing polluters tofinance pollution prevention will improve environmental quality. Moreover,there exists an “optimum pollution tax rate for economic growth” and an“optimum pollution tax rate for welfare” to maximize the economic growthrate and welfare, respectively. On the other hand, raising the R&Dsubsidy rate is helpful for increasing the economic growth rate.Furthermore, there exists an optimum R&D subsidy rate to maximizewelfare.