> For the complete documentation index, see [llms.txt](https://docs.aethlabs.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.aethlabs.com/microaethalometer-tm-ma450/quick-start-guide/recommendations-and-best-use-practices.md).

# Recommendations and Best Use Practices

**Instrument Settings:** We recommend getting started using the 60 second timebase and 150 ml/min flow rate, with 5 wavelengths enabled and DualSpot® loading compensation. After deploying the instrument in your application and collecting some data, these settings can be adjusted to suit your requirements.

**SingleSpot™ vs DualSpot®:** The DualSpot® loading compensation method corrects for the optical loading effect and provides additional information about aerosol optical properties. It simultaneously collects aerosol samples on two analysis spots in parallel at different face velocities while measuring the rate of change in absorption of transmitted light as particles load on the filter. DualSpot® is an optional, user-selectable feature in the microAeth® Manager program and is the recommended default for the MA450. SingleSpot™ with a lowered ATN threshold of 50 (with UV enabled) usually has minimal loading effect in the IR channel.

The timebase, flow rate, and wavelength selection have the greatest impact on filter tape consumption and power use, as well as on data quality.

**Individual Data Point Noise:** Instrumental noise contributes a random perturbation to the 'ideal' BC data. Its magnitude is inversely proportional to the timebase and flow rate settings. Data collected on a 1 second timebase should always be smoothed or averaged over longer periods, unless measuring high concentrations where the instrumental noise is negligible.

**Effects of Contamination, Vibration, and Impact:** These are primarily affected by the timebase setting; an increased flow rate will also reduce the effect.

| 1 second   | 5 seconds | 10 seconds | 30 seconds | 60 seconds | 300 seconds |
| ---------- | --------- | ---------- | ---------- | ---------- | ----------- |
| very large | large     | large      | moderate   | low        | least       |

**Choosing the Tape Advance ATN for your application:** Choosing the right tape advance ATN trigger helps ensure the integrity of your measurement by reducing possible loading effects. Loading effects are variable, aerosol dependent, and are not always present. The range of the Tape Advance ATN trigger is 1 to 100. The lower the trigger setting, the lower the impact of loading effects on the data, at the expense of more tape consumption. Your SingleSpot™ vs DualSpot® selection, flow rate, and enabled wavelengths also affect how frequently you reach your ATN setpoint and the tape advance frequency.

**Continuous Deployment and Monitoring:** For unattended continuous monitoring stations, enable **AutoSample** so the instrument automatically resumes sampling and recovers after a power interruption. Monitor the tape position and plan cartridge replacements before the tape runs out. The MA450's built-in **WiFi** can transmit data to the AethLabs server for remote access, and the instrument can also output **RS-232** serial data through the sealed **M12 SERIAL** connector for real-time integration with data acquisition systems. In high-humidity environments, install the optional built-in **Nafion dryer** to reduce moisture artifacts in the sample stream.

**Maintenance:** To keep the MA450 producing quality measurements, keep the instrument and its air passageways, optical chambers, and internal components clean. We recommend, at a minimum, an annual maintenance service at AethLabs or an authorized service center.