翻译成英文：如果在这里建一座工厂，将会影响这里的环境。

If a new factory is to be built here, the environment around will be affected.

更好的一点的话就是用虚拟语气了，不过口语中基本用不到
If a new factory was to be built here, the environment aaround would be affected.

If a plant is built here, the environment will be spoiled.

It would be bad for environment if a factory were set up here.

If you build a factory here, it will affect the environment around.
或者
If a factory is built here, it will affect the nearby environment.