隨著世界各國追求經濟快速成長的同時，卻也帶來自然環境的加速破壞。因此，經濟活動對環境影響的相關議題備受經濟學者與環境學者的重視。本論文分別將效率工資、租稅逃避以及社會規範等理論應用於環境議題，以祈對環境政策的效果有更深一層的瞭解。

首先，第二章設定一個跨時最適的效率工資 (efficiency wage) 模型，該模型除了沿續效率工資理論所強調的工資誘因外，同時也考慮到廠商的污染防治行為可以促進員工的健康，進而提高員工的工作效率。據此，廠商目前的污染防治支出雖然增加了生產成本，但卻也換得未來的產出增加。所以，廠商將其污染防治支出視為是一種環境的投資，透過這個管道可以解釋廠商有誘因主動從事污染防治的工作。另外，若政府提高對廠商污染防治支出的補貼，該章也分析了經濟體系的短期動態調整以及長期的穩定均衡。

其次，經濟學者建議政府提高污染稅，並且將增加的稅收移轉用來補貼廠商的勞動雇用。藉此，希望同時能夠改善環境品質並刺激就業量，即達到所謂 ”雙重紅利” (double dividends) 的結果。第三章在自動申報(self-reporting) 的機制下，分析政府執行稽查政策與廠商匿報污染稅行為的互動關係。該章分別探討政府對勞動補貼以及對污染防治補貼的效果，我們發現：有效污染稅收的多寡將影響達成雙重紅利的條件；同時，提高罰金與加強稽查也可能得到雙重紅利的效果。

第四章將建立一個環境的社會規範 (environmental social norms) 模型，描述違規廠商由心理層面所產生的社會約束成本，藉以解釋雖然面對違規的預期處罰很低但是廠商遵守污染標準的比例卻很高的矛盾現象。另外，Frey (1997) 指出外在的價格機制可能會排擠廠商內在的環保動機，該章的模型明確地將此排擠 (crowding-out) 效果納入考慮。藉此，我們發現當排擠效果大於價格效果 (以價制量) 時，提高污染稅可能使違規的廠商數目增加，整體社會的污染量反而增加。因此，價格機制也許不是對抗污染的有效環境政策。

In this dissertation three essays are written to address the environmental policies, they are the applications of efficiency wages, tax evasion, and social norms, respectively.

In Chapter 2, by presenting an efficiency wage model embodying intertemporal optimization, we propose a channel to illustrate the willingness of firm’s abatement activities.　The idea is that worker’s efficiency on working is positively related to his stock of health capital, and that abatement will raise the flow of health.　The firm thus will treat the abatement expenditure as an environmental investment since it will raise the stock of health capital and hence the working efficiency in the future.　In addition, we analyze the firm’s responsiveness when the authorities raise the subsidy on firm’s abatement expenditure.　It is found that the firm will raise both employment and abatement expenditures and lower its wage offer in the long run.

An increase in environmental taxes recycled to subsidize employment may yield a so-call “double dividend” in the sense of improving environmental quality and boosting employment simultaneously.　In Chapter 3, we address the possibility of double dividends when environmental tax revenues are collected incompletely due to firms’ noncompliance.　Taking account of the pollution tax evasion, we find that a double dividend may happen under some restrictive conditions.　However, the conditions for the existence of double dividends are crucially dependent upon the enforcement of tax collections.　In addition, we also find that a higher fine and more intensive inspection may create double dividends.

In Chapter 4, we establish an environmental social norm model to embody the collective environmental actions among firms.　The model provides a plausible explanation for the puzzling phenomenon of empirical findings whereby a high compliance rate co-exists with a low expected penalty.　Frey (1997) argues that the intrinsic motivation of environmental norms is often crowded out by extrinsic pricing (or tax) instrument.　We show that, if the crowding-out effect of the tax instrument dominates the incentive effect, tax incentives could increase pollution, rather than decrease it.