Central California Ozone Study (CCOS) - Desert Research Institute

CCOS Field Operations Plan Version 2: 5/31/00
• Calculate the corrected flow meter reading in standard liters per minute using the
following equation:
Q std = a x (Q o - (z c - z)) + b
where Q 0 is the flow meter reading
z is the measured mass flow meter zero reading
z c is the mass flow meter zero reading at the time of the certification
a is the certification slope
b is the certification intercept
Dry Test Meters
• Attach the dry test meter to the line being audited.
• Reset the audit stopwatch.
• At a convenient reference point on the dry test meter dial, start the stop watch and record
the exact initial test meter reading.
• Allow at least 1 minute for the test to run.
• At a convenient reference point on the test meter dial, stop the stopwatch and record the
exact final dry test meter reading.
• Repeat the above steps 2 times for the same volume as defined by the dry test meter.
• Calculate an average of the three times obtained from the stopwatch.
• Calculate the measured volumetric flow rate using the following equation:
Q vol = V / t
where V is the volume measured by the dry test meter
t is the average stop watch reading
4.5.6 NMOC/Carbonyl Samplers
Thru-the-probe performance audits will be conducted at each NMOC/Carbonyl
monitoring site to assess the integrity of the sampling equipment and transport system, and the
accuracy of the analytical methods used by the laboratory to measure the ambient concentrations
of VOCs. In a TTP audit, a gaseous mixture of VOCs prepared by NIST is mixed with purified
air under controlled conditions and introduced into the sampling probe of a air sampler. The
sampler collects the audit gas mixture in a humidified stainless steel canister over the normal
sample period. The audit sample is then shipped to the laboratory along with other regular
ambient samples, where it is analyzed following normal standard operating procedures.
4.5.7 Continuous Air Quality Samplers
4.5.7.1 Audits Conducted by Parsons ES
Ozone. The audit zero air and ozone transfer standard are set up and allowed to warm-up
for at least one hour. Once the audit equipment has reached a constant operating temperature,
Chapter 4: QUALITY ASSURANCE 4-19