External considerations Structural designs or redesigns that will increase degradation rates and ■ those that reduce volatility(挥发 FE), persistence in the environment or conversion in the environment to biologically active substances represent examples of major external considerations for reducing exposur 四大学化学学院 2002年7月26日四川大学化学学院 2002年7月26日 4 External considerations ◼ Structural designs or redesigns that will increase degradation rates and ◼ those that reduce volatility（挥发 性）, persistence in the environment or conversion in the environment to biologically active substances ◼ represent examples of major external considerations for reducing exposure