EPA is proposing to reduce the annual NAAQS limits for PM2.5 from 15 ug/m3 to 12 or 13 ug/m3: http://www.epa.gov/pm/actions.html#jun12
Anecdotal info from regulators is that this new standard will push a lot more areas into nonattainment for PM2.5. This may result in more enforcement of residential sources of PM2.5, such as wood smoke. See State Implementation Plans for details on how each state complies with PM2.5 NAAQS requirements (http://www.epa.gov/airquality/urbanair/sipstatus/). Many northern states identify wood smoke as a major source of PM2.5.
Traditional industry is expected to complain about these new standards, but agriculture and gravel/sand-related industry will complain more. Industrial sources of PM2.5 are minimal when compared to fuel combustion sources and dust/dirt. http://www.epa.gov/cgi-bin/broker?_service=data&_debug=0&_program=dataprog.national_1.sas&polchoice=PM Fuel combustion is a source category used by EPA for burning anything from biomass to coal.
The proposal is open for public comment for 60 days. Now’s your chance to tell EPA to reduce the allowable annual PM2.5 limits to 12 or even 11 ug/m3. This is the primary driver for any wood smoke regulations.