本文建立一個受到社會環保意識網絡外部性影響的消費者效用函數的垂直差異獨佔模型。並且假設市場是只有一家提供產品的獨佔市場，消費者在購買飲料前會選擇要使用一次性飲料杯、租借環保杯還是自備環保杯來購買飲料。本文目的旨在藉由分析社會環保意識對市場均衡的影響，達到社會福利之改進。除此之外，亦加入立法管控、徵費、獎勵金等各干預政策的狀況，分析這些政策環保意識提升帶來之差別。

結果顯示，環保意識水平相對低時，消費者偏好使用一次性飲料杯，其次自備，最後租借。當環保意識的提升後能減少人們對一次性飲料杯之選擇，有部分消費者離開市場，導致市場涵蓋範圍縮小，難以確定社會福利有否改善;當環保意識水平相對相對高時，消費者偏好變為使用租借環保杯，其次自備，最後一次性飲料杯。雖然擴大了市場涵蓋範圍，但也因為更多人使用一次性飲料杯造成更多污染。只有位於兩者之間時，更多人轉使用環保杯，由於環保意識並非政府能輕易控制之變數，因此需要使用政策干預來達至同樣的效果。接著我們知道，立法管控銷售會使環保意識之效果消失，所以此政策僅適合運用在一次性飲料杯造成環境污染程度相當大的情況下，否則失去環保意識的市場範圍擴大效果，在長遠下對社會福利水平是不利的。徵費和獎勵金政策，它們造成的效果相似，有利於消費者盈餘和利潤，鼓勵民眾使用環保杯，但獎勵金相比徵費，對於金額大小使價格的變動會有更大程度之反應。

This paper delves into the implications of environmental awareness on consumer choices within the beverage market, specifically focusing on the selection between disposable cups, rented eco-friendly cups, and personal eco-friendly cups. We also assess the effectiveness of four potential government interventions: legislative control, taxation, incentives.

Our findings reveal that heightened environmental awareness can positively influence social welfare, albeit potentially limiting market coverage. We offer the following policy insights:

Legislative Control: While this approach can be effective in cases of significant environmental pollution, it may be over-correction to market . Careful consideration of its application is warranted.

Taxation and Incentives: These policies have similar effects. The stimulate consumer surplus and business profitability. How to find the maximun society benefit price is approach is essential to strike a beneficial equilibrium.

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