fine particulate matter (PM) and the implications for metalcasting facilities in July 2012. In the past three years, a number of develop- ments have occurred, including the lowering of the annual stan- dard. Tis article provides updated information and perspectives on this topic, which may have signifi- cant consequences for metalcasters wanting to expand and modernize their facilities.
M 1
ODERN CAST- ING last discussed the regulation of
most metalcasting sources. In addi- tion, emission levels have consider- able variability, especially for CPM. Te U.S. Environmental Protection Agency (EPA)’s “Compilation of Air Pollutant Emission Factors” (or AP-42) is of limited help since most of the emission factors are for total particulate matter. Limited data exists on the size distribution of PM to allow for accurately estimating the PM2.5
ably on stack test data. A limited amount of data is available for use in estimating PM2.5
portion. Lastly, none of the What is PM2.5 ?
liquid particles that are equal to or smaller than 2.5 microns, which is approximately 30 times thinner than the diameter of a human hair. Tese fine particles can be emitted directly from a metalcasting facility or can form as a result of gaseous emissions that condense to form particles downstream. As such, when PM2.5
able (solid) particulate is measured as well as condensable particulate matter (CPM).
2 How are PM2.5 emissions
from metalcasting sources estimated?
emissions from metalcasting sources is important because these estimates are used: 1. To determine whether certain
Accurately estimating PM2.5
rules may apply. 2. As the basis for enforceable
emission limits. 3. As the basis of air quality assessments. 4. To predict the ability to comply
with enforceable limits. Estimates can be based on
general emission factors or prefer- August 2015 MODERN CASTING | 37 PM2.5 consists of solid and
factors for foundry processes include the condensable portion of the emis- sions. As a practical matter, estimat- ing emission levels can be a fairly complex process of selecting the best data available and also assessing the potential variability of emissions and its impact on the specific regulatory use of the emissions estimates.
3 is evaluated, both filter- PM10 PM2.5
emissions from
4
How do you measure PM2.5 emissions from your facility?
EPA has specific test methods
for measuring both filterable PM2.5 emissions (EPA Method 201A) and
CPM (EPA Method 202). Method 201A measures the weight of the solid or liquid particles that are cap- tured on a filter (after the particles larger than 2.5 microns are segre- gated out). Method 202, the speci- fied method for measuring CPM, is applied downstream of the filter and measures condensed materials that may have passed through the filter. Te combined result of these
two methods is reported as the total PM2.5
value.
What are the principal PM2.5
metalcasting facilities?
including material handling pro- cesses, natural gas combustion, diesel engines, scrap pre-heaters and emis- sions from roadways.
cal metalcasting facilities include melting, sand handling, pouring and shakeout. Filterable emissions from these processes can be significantly reduced using fabric filters or high efficiency wet scrubbers. CPM emis- sions are not effectively controlled by baghouses and can be significant, especially from the pouring, cooling and shakeout processes where they can be much more prevalent than the controlled filterable emissions. Other smaller emission sources also contribute to total PM2.5
Te emission sources with the largest PM2.5 emissions at typi-
emissions 5 ).
Table 1. Daily and Yearly National Ambient Air Quality Standards 24-Hour Average (µg/M3
) 150 35 NA 12 PM10 and PM2.5
Table 1 summarizes the current National Ambient
What national ambient air quality standards apply to PM2.5
?
Air Quality Standards (NAAQS), which are expressed as a concentra- tion in micrograms per cubic meter (µg/M3
lowered from 15 µg/M3 to 12 µg/ M3
Te PM2.5 annual standard was in March 2013. In December
2014, EPA designated 38 counties in
emission sources at
Annual Average, (µg/M3
)
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