Determination of Low Level Particulate Matter Emissions from Stationary Sources – USEPA Method 5i

USEPA Method 5i is used for the determination of low level Particulate Matter (PM) emissions from stationary sources.
 
Particulate is withdrawn isokinetically from the source and collected on a 47 mm glass fiber filter maintained at room temperature of 120 ± 14°C (248 ± 25°F).  The PM mass is determined by gravimetric analysis after the removal of uncombined water.  Specific measures in this procedure designed to improve system performance at low particulate levels include:

• improved sample handling procedures;
• light weight sample filter assembly;
• use of low residue grade acetone.

The method is performed using a paired train configuration.  The trains are operated as co-located trains (two trains collecting from one port) or as simultaneous trains (separate trains operating from different ports at the same time).  The procedures for calculating precision of the paired trains are provided in the method.
 
This method is most effective for total PM catches of 50 mg or less.  The method was initially developed for performing correlation of manual PM measurements to PM continuous emissions monitoring systems (CEMS), however it is also useful for other low particulate concentration applications.
 
Accuracy is improved through the minimization of systemic errors associated with sample handling and weighing procedures.  High purity reagents, all glass, grease free, sample train components, and light weight filter assemblies and beakers, each contribute to the overall objective of improved precision and accuracy at low particulate concentrations.
 
There are numerous potential interferences that are encountered through method sampling and analysis.  This method should be considered more sensitive to the normal interferents typically encountered during particulate testing because of the low level concentrations of the flue gas stream being sampled.  Care must be taken with respect to the following:

• field contamination, especially the filter
• sample loss
• balance room conditions
• electrostatic charges
• sulfates
• acid gases