"Condensables" are the things like Sulfur Dioxide. Although it is a gaseous pollutant by itself, it can also combine with water vapor in the air and will condense around smaller particles as it travels down wind. Thus, very small amounts of fine particulate pollution (PM2.5) can "grow" as the SO2 condenses with water vapor around fine particles to produce larger and larger aerosols over time.
An example of this was a nonattainment determination a few years ago in Marion County. EPA determined that the Fort Martin plant was a contributor to Marion County's nonattainment of the fine particle standard, even though the monitors at the Morgantown airport showed attainment. EPA concluded that fine aerosols from Fort Martin "grew" as they condensed so that levels that were in attainment in Morgantown grew by condensation until they turned into nonattainment in Fairmont.
WV-DEP has always resisted including "condensables" in the PM2.5 determination. There are relatively few PM2.5 monitors in WV, so only a few counties have on-site data to document nonattainment. But if condensables were included, many more counties could be found to be in nonattainment based on known emissions of SO2. Thanks for the note Jonathon.
JBK
P.S. As you know, these ultra-fine particles (PM2.5) are among the greatest health concerns to humans because they are so easily inhaled deep into the lungs. PM2.5 is associated with emphysema, heart disease, and even cancer.
Jonathan Rosenbaum jr@wvcompletestreets.org 5/14/2013 11:51 PM
I thought this may be of interest:
https://www.federalregister.gov/articles/2013/05/09/2013-10935/approval-and-...
(j)(1) EPA is disapproving a narrow portion of West Virginia's August 31, 2011 submittal because it does not satisfy the requirement that emissions of PM 2.5 and PM 10 shall include gaseous emissions which condense to form particulate matter at ambient temperatures. This disapproval extends only to the lack of condensable emissions within the definition of “regulated NSR pollutant,” found at 45CSR14 section 2.66, and does not alter EPA's October 17, 2012 (77 FR 63736 ( https://www.federalregister.gov/citation/77-FR-63736 )) approval of the remaining portions of West Virginia's August 2011 SIP submittal. (2) EPA is disapproving specific portions of West Virginia's infrastructure SIP submissions dated December 3, 2007, December 11, 2007, April 3, 2008, October 1, 2009, October 26, 2011, and February 17, 2012 which address certain obligations set forth at CAA sections 110(a)(2)(C), (D)(i)(II) and (J) relating to the West Virginia PSD permit program. Because West Virginia's definition of “regulated NSR pollutant” in 45CSR14 does not address condensables for PM 2.5 and PM 10 emissions, EPA is determining that West Virginia's infrastructure SIP submissions do not meet certain statutory and regulatory obligations relating to a PSD permit program set forth at CAA sections 110(a)(2)(C), (D)(i)(II) and (J) for the narrow issue of condensables as set forth in the following table. Submittal datesNAAQSInfrastructure element(s) disapproved in this action December 11, 2007; April 3, 20081997 PM2.5110(a)(2)(D)(i)(II). December 3, 2007; December 11, 20071997 ozone110(a)(2)(D)(i)(II). October 1, 20092006 PM2.5110(a)(2)(D)(i)(II). October 26, 20112008 lead110(a)(2)(D)(i)(II), (C), and (J). February 17, 20122008 ozone110(a)(2)(D)(i)(II), (C), and (J).