METHOD 201A, AMENDED - The purpose of Method 201A is to measure particulate matter emissions equal to or less than given nominal aerodynamic diameter(s). In general, a gas sample is extracted from a stationary combustion source at a predetermined constant flow rate through in-stack sizing devices.

As amended, Method 201A now combines the existing method (PM10) with a PM2.5 cyclone to create a sampling train that includes a total of two cyclones (one cyclone to size particles with aerodynamic diameters greater than 10micron and one cyclone to size particles with aerodynamic diameters greater than 2.5 micron) and a final filter to collect particles with aerodynamic diameters less than or equal to 2.5 micron. The PM2.5 cyclone is inserted between the PM10 cyclone and the filter of the Method 201A sampling train. PM10 + Filter = measures total and PM10 emissions, PM2.5 + Filter = measures total and PM2.5 emissions, PM10 + PM2.5 + Filter = measures PM10 and fine particulate matter: If the gas filter temperature exceeds 30 deg C (85 deg F), to measure total primary (direct) particulate matter (both the filterable and condensable components) then you must combine the procedures in Method 201A with the procedures in Method 202 for measuring condensable particulate matter. However, if the gas filtration temperature never exceeds (30 deg C (85 deg F), then use of Method 202 is not required to measure total primary particulate matter. Method201A cannot be used to measure emissions from stacks that have entrained moisture droplets (e.g., from a wet scrubber stack). Method 201A is not applicable for stacks with small diameters (18 inches or less).