ACTRIS

Station personnel should be able to handle all but yearly inspections. Here is a list of instrumentation each station should have.

• All the necessary tools and chemicals for cleaning and other tasks
• Drycal flow meter. This flow meter should be intercompared against Helsinki standard annually 
• TSI 0-200LPM flow meter, which should be compared against Drycal twice a year
• HEPA filter
• Hand held meter for pressure, temperature and pressure. To be calibrated/intercompared every second year
• Nebulizer for PSL testing (ultrapure water needed)
• HV probe with high impedance

Clean the inlets, when required, at least once per year. Remember to keep aerosol drier sheath flows on May-Sep. RH should be below 40%. Temperature in the measurement space should preferably be stable at around ~23 °C+/-2 °C. Fluctuations in temperature should be minimized when possible.

CPC

• Follow the concentrations and status values from Wiki/Grafana as often as possible. Check also the intercomparison against SMPS total concentration, if possible
• CPC flow should be checked every month. If the nozzle or orifice differential pressure starts to change or are too low, check inlet flow rate immediately. Check the default CPC flow rate from CPC screen, 2% difference is still accepted. 
• Zero check every month with HEPA filter. If station has a CPC in the SMPS with similar cut off size, compare concentrations with outdoor air when no UF particles present.
• Yearly checks
  • Do the monthly checks
  • Clean the CPC flow path and change the wick. Clean nozzle and critical orifice in ultrasonic path. If you know how to clean optics, do that
  • Check that CPC temperatures are the same, when you start the cold instrument and against a reference
  • Check the CPC pressure against a reference
  • Check the CPC concentration against a reference CPC with outdoor air when no UF particles present. If you have a concentration calibration setup at the station, better to use 40nm test aerosol with different concentrations min-max the values recorded at the station
• Every second year CPC to Tropos workshop. If Tropos calibration is not done, ship the instrument to Helsinki for calibration.

SMPS

• Aerosol size distribution and the instrument status values should be followed as often as possible from the Wiki/Grafana pages. Check also the ratio between SMPS and total CPC, if possible. Difference can be max 15%
• Aerosol inlet flow and CPC flow should be measured every month. Inlet and outlet flows should not deviate more than 2% from each others. Also measured CPC flow should not differ more than 2% from the default value on the CPC screen.  Sheath flow meter should be checked against a reference. Update flows or flow corrections to SMPS measurement program configuration and check that NRT data submission files have correct aerosol flow rates
• Zero check with HEPA filter every month
• Sheath flow meter, aerosol flow meter, pressure, temperature and RH  should be checked twice a year against a reference. If
• Yearly checks
  • Check the CPC as the total CPC is checked
  • Clean sample lines (not the neutralizer) and DMA
  • Compare temperature, RH and pressure sensors against a reference and adjust in SMPS config
  • Compare HV source output against high impedance HV probe and adjust calibration in SMPS config
  • PSL check with 100nm (or  200nm) particles, up to 3% difference accepted. PSL test can be used also test and adjust the SMPS delay time. 
• Neutralizer should be changed according to the  manufacturer instructions. It can be cleaned without opening with instructions given by experts in Helsinki
• Every second year SMPS to Tropos workshop. If Tropos calibration is not done, ship the instrument to Helsinki for calibration.

APS

• Follow the instrument size distribution and status plots from Wiki/Grafana as often as possible. Inlet blockage typically causes very high values and laser failure zero values.
• Measure aerosol flow and sheath flow twice a year. Adjust, if more than 5% ? difference (instructions for adjustment should be found)
• PSL test with 1.0um PSL (10% difference accepted) twice a year
• Clean the inlet nozzle twice a year

Nephelometer

• Follow the concentrations and status values from Wiki/Grafana as often as possible. Scattering usually 0-50 Mm^-1. Event peaks can spike to above 100 Mm^-1. Backscattering should be less than total scattering. Wavelengths should go from low to high red-green-blue.
• Daily zero check should be automatically scheduled from instrument settings. Zero should be between -2 Mm-1 and 2 Mm-1 .
• Perform full calibration with CO2 and air every third month
• Check flow is rather stable at 5 L/min +- 1L/min.
• Yearly checks
  • Temperature and pressure sensors should be intercompared against a reference
  • Photon counts should be checked. Shutter photon counts 0.8-1.3M, measure photon counts 1M-20M and dark photon counts below 1k
  • Leak test
  • Cleaning only when necessary in problem cases. This includes abnormal values, failed zero checks or calibrations or bscat values are higher than scat.
• Every second year Nephelometer is sent to Tropos workshop. If Tropos calibration is not done, TBD.

Aethalometer

• Follow the concentrations and status values from Wiki/Grafana as often as possible. Wavelengths should go from low to high 950->370 nm or channels 7->1
• Aethalometer flow should be checked every month (5 L/min). Measured flow is compared to instrument value. This requires converting to standard pressure and temperature Q = Q_meas * T/T_0 * P_0/P (NIST, 101325 Pa, 0 °C). (5 L/min is around 5.4 L/min, when T ≈ 20°C ja p ≈ 1000 hPa)
• Monitor the filter tape. When empty change new filter tape. 
• Regularly monitor the spot shape. Spot shape should be sharp. Diffuse edges indicate a problem with the closing mechanism.
• Yearly checks (pref. twice per year)
  • Perform automatic tests (clean air, stability, flow verification, leakage test)
  • Flow calibration if necessary
  • Cleaning of the optical head when necessary. Ethanol or isopropanol.
• Every second year Aethalometer is sent to Tropos workshop. If Tropos calibration is not done, TBD. Hyytiälä MAAP and AE33 should not go to the workshop at same time.

MAAP

• Follow the concentrations and status values from Wiki/Grafana as often as possible.
• MAAP flow should be checked at least every month (16.67 L/min). Adjust when necessary.
• Monitor the filter tape. When empty change new filter tape. 
• Regularly monitor the spot shape. Spot shape should be sharp. Diffuse edges indicate a problem with the closing mechanism.
• Yearly checks
  • Check pressure and temperature sensors
  • Check zero
• Every second year MAAP is sent to Tropos workshop. If Tropos calibration is not done, TBD. Hyytiälä MAAP and AE33 should not go to the workshop at same time.

Meteorology