Bcmwiki: Wiki update: sync with manual and dev docs (2026-03)

2026-03-08T13:10:10Z

Wiki update: sync with manual and dev docs (2026-03)

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== Best Practices ==

=== Environment ===

* Keep the device '''away from direct sunlight''', radiators, and fireplaces — it is sensitive to temperature and lighting changes.
* Position the inlet away from localized emission sources unless intentionally measuring them.
* For indoor use, avoid placement near HVAC vents or drafts.

=== Sampling Configuration ===

* '''Sample frequency:'''
** Ambient immission monitoring: '''180–600 seconds''' (3–10 min)
** Direct emissions from wood stoves (µg vs ng range): '''10–30 seconds'''
** Note: increasing frequency may increase noise.

* '''Airflow:'''
** Minimum 40 mL/min, maximum 400 mL/min (hardware-dependent).
** Higher airflow improves signal strength but loads the filter faster.

{| class="wikitable"
! Pollution Level !! Daily Avg BC !! Recommended Airflow
|-
| Heavy pollution || >2000 ng/m³ || 50 mL/min
|-
| Typical urban || ~500 ng/m³ || 100–250 mL/min
|-
| Low pollution || <500 ng/m³ || 300–400 mL/min
|}

When '''Auto Flow Control''' is enabled, the device adjusts airflow automatically based on measured BC concentration — reducing flow when BC is high (to extend filter life) and increasing flow when BC is low (for better signal).

=== Signal Quality ===

Signal-to-noise ratio improves with:
* Higher BC loads
* Higher air volume per sample
* Smaller sample spot diameter

'''Filtering:''' Apply median/average filtering (denoise slider) to reduce noise. The rolling average is closer to the "real" value than individual data points.

'''Calibration:''' Always calibrate after every filter change for reliable filter status indication and accurate measurement.

=== Filter Management ===

* At the default airflow in a typical urban environment (~500 ng/m³), a filter lasts approximately '''3–5 days'''.
* In heavily polluted areas, a filter may saturate in '''6–12 hours'''.
* The filter is considered saturated at approximately '''30% attenuation'''. Beyond this, accuracy degrades — values are flagged in the CSV.
* The [[Configuration#Measurement Tab|Airflow Reference table]] in Settings helps estimate filter lifetime for your conditions.

=== Supported Filter Papers ===

{| class="wikitable"
! Filter Paper !! Scattering Correction Factor
|-
| Pall T60A20 || 1.0
|-
| AE33 Filter || 0.75
|-
| AE51 Filter || 1.0
|}

Other filter papers can be supported by determining their scattering factor. Send a sample to jd@bcmeter.org for calibration.

Best practices - Revision history

Bcmwiki: Wiki update: sync with manual and dev docs (2026-03)