Here’s a good quality remote switch for a heavy duty fan (also available elsewhere):
http://www.leevalley.com/en/wood/page.aspx?p=67020&cat=1,42401,72660
@Mike_C makes a good point. about fumes. A further caution - my understanding is that charcoal filters primarily reduce odor, and depending what you are cutting, may do little or nothing in terms of reducing dangerous gases.