• The Bay Area Air Quality management office has a nifty little handbook section that deals with coffee roasting operations, and what their limits are. It contains some interesting background information that you may or may not have known, including discussion of how this crap ends up being such a huge problem, and what is generally done to control it. Since your irritating neighbors don't seem to understand this (or since whatever they're doing doesn't seem to work), you might want to throw
• carcinogenicity information from NIH at them, and mabye scare them witless. The best part?

  There is sufficient evidence for the carcinogenicity of acetaldehyde in experimental animals ... when administered by inhalation, acetaldehyde increased the incidence of squamous cell carcinomas and adenocarcinomas in the nasal mucosa of rats of both sexes and laryngeal carcinomas in hamsters of both sexes.

  (Emphasis mine, for obvious reasons.) It does go on to say, however, that hamsters were OK when lower exposure levels were used -- good for the hamsters; who knows what it means for humans.

• California's Air Resources Board publishes a nifty fact sheet on acetaldehyde. (You need Adobe Acrobat to read this document.)
• NIOSH (and the CDC, source of all good things in the public health world) has a neat-o international chemical safety card for acetaldehyde. Since coffee roasting also produces other, um, junk, you might find these helpful:
  • Acetic acid
  • Acrolein
  • Formaldehyde
  (Just some of the other stuff that gets kicked out by the guys upwind.)

Good luck, kids!