13. Energy, Air, Water, Amenities Air pollution, solid waste, waste heat, waste pollution The Materials Balance Model :the interdependence of economic activity and the nature- closed system and open system Nature Output market Factor market Households Firms Natural resources drawn from nature Residuals from consumption Residuals from production Suppl y of goods and services Reuse--recycling--recovery Demand for resources Supply of resources Demand for goods and services Recovery --- recycling -- reuse