- 1:What is the overall measurement procedure?
- Click here to view the overall measurement procedure.
- 2:How to assemble the Ogawa Passive Sampler?
- Click here to view the assembly diagram of the Passive Sampler.
- 3:How to setup the Passive Sampler for outdoor use?
- Click here to view the Set Up Diagrams for Outdoor use of the Passive Sampler
- 4:How to wash the sampler?
- Rinse in Di-ionized water, allow to dry on clean paper towel. DO NOT USE HEAT.
- 5:What is the recommended sampling height?
- 2.5 meters or 8 feet.
- 6:Transporting the Passive Sampler to the site?
- After assembly, the loaded sampler is placed into the re-sealable plastic bag, the bagged sampler is placed into the brown airtight container provided and taken to the exposure site.
- 7:How long can a loaded sampler be kept before it is used?
- Once the sampler is loaded and placed in its airtight vial, it should be kept at standard room temperature, as long as it is to be taken on site within several days.
- 8:What pads are loaded into the Passive Sampler for the collection of each specific gas?
- Click here to view the configuration of the Passive Sampler for various gases.
- 9:What is the 'Control or Blank Pad'?
- It is a pre-coated pad, from the same batch, that is loaded into the sampler and put in its brown airtight vial to be used as a ‘control’. This ‘control’ sampler should accompany the samplers that are to be exposed, so it is subject to the same temperatures and conditions as the others, but the control sampler should never be opened, except to remove the pads and placed into an airtight shipping vial.
- 10:What is the storage time for the pre-coated pads?
- If pads are sealed in original glass vial within the aluminum vacuum pack – 90 days in refrigerator or 1 year in freezer.
- 11:Is there a certain refrigerated temperature to store the pads?
- Not really, just the standard household refrigerator temperature. Note: Pads should be removed from the refrigerator about 12 hours before exposure for the purpose of equilibrating to the room temperatures. This is done to prevent condensation from forming on the pad. Moisture is the enemy of the coated pad, as it can remove some of the collecting material.
- 12:Can NOx value alone be obtained by using one NOx pad?
- The concentration of NOx cannot be obtained by just using one NOx pad.
The concentrations obtained are then both used in the analytical formula shown in the protocol.The calculation for NO is done by subtracting NO2 from NOx.
- 13:How many pads are needed for each type of sampling?
- You will need one PS-100 sampler for every site and every gas that your customer wants to sample.
- 14:What are the exposure and collection times for the absorption?
- Depending on concentration, from as little as 8 hours and up to 30 days. Ideally, no less than 24 hours.
- 15:How long can an 'exposed pad' be kept?
- Once the pad is exposed, it loses much of its sensitivity and can be stored in a normal room temperature. Naturally, the sooner the exposed pad is taken to the lab for analysis, the better. The coated pads are not affected by normal temperatures but should not be put in direct sunlight or in heated areas.
- 16:Does Barometric pressure affect collection results?
- As long as the calculations are for units of ppb, the passive sampler measurements are independent of barometric pressure, for any gas.
O3 ANALYSIS uses two O3 pads that are analyzed together, and is considered one analysis cost.
NO Analysis uses One NOx pad and one NO2 pad on either end of the sampler.
NOx = NO2+NO and NO = NOx-NO2.
Each side is a separate analysis cost.
- 17:How to extract the exposed pad for analysis?
- Click here to view the diagram for anlayzing the Passive Sampler.
- 18:What are the absorption reagents, analytical methods and analytes?
- Click here to view the chart for Reagents, Methods and Analytes.
- 19:What is the calculation for gas concentration for ambient air?
- Click here to view the calculation for concentration in ambient air.
- 20:What is the lowest detectable range?
NO2 24 hr 2.3 ppb 168 hr 0.32 ppb NOx 24 hr 2.3 ppb 168 hr 0.37 ppb SO2 24 hr 3.8 ppb 168 hr 0.54 ppb 03 24 hr 2.7 ppb 168 hr 0.39 ppb NH3 24 hr 2.3 ppb 168 hr 0.32 ppb
- 21:What is the upper detectable range?
NO2 24 hr < 25 ppm 168 hr < 3.6 ppm NOx 24 hr 2 < 5 ppm 168 hr < 3.6 ppm SO2 24 hr < 25 ppm 168 hr < 3.6 ppm 03 24 hr < 0.8 ppm 168 hr < 0.11 ppm NH3 24 hr < 25 ppm 168 hr < 3.6 ppm
- 22:What is the normal detectable range?
NO2 24 hr 0-25 ppm 168 hr 0- 3.6 ppm NOx 24 hr 0-25 ppm 168 hr 0- 3.6 ppm SO2 24 hr 0-25 ppm 168 hr 0- 3.6 ppm 03 24 hr 0-0.8 ppm 168 hr 0-0.11 ppm NH3 24 hr 0-25 ppm 168 hr 0- 3.6 ppm
- 23:What is the response time (R.T.)?
- Response Time = L2/2D = 0.9 (sec.)