Best practices - Revision history

Bcmwiki: Remove eBcMeter-specific content from the public bcMeter documentation

2026-07-31T23:45:01Z

Remove eBcMeter-specific content from the public bcMeter documentation

← Older revision		Revision as of 00:45, 1 August 2026
Line 4:		Line 4:

	* Keep the device '''away from direct sunlight''', radiators, and fireplaces — it is sensitive to temperature and lighting changes.		* 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~~.		* Position the inlet away from localized pollution sources so readings represent the surrounding air.
	* For indoor use, avoid placement near HVAC vents or drafts.		* For indoor use, avoid placement near HVAC vents or drafts.

	=== Sampling Configuration ===		=== Sampling Configuration ===

	* '''Sample frequency:'''		* '''Sample frequency:''' For ambient monitoring, use '''180–600 seconds''' (3–10 min). Shorter intervals can increase noise.
	** 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:'''		* '''Airflow:'''

Bcmwiki: Consistency pass 2: airflow range via Configuration, multi-wavelength as in-development, ESP32/Pi CSV filename split, legacy sensor wording

2026-06-08T18:47:40Z

Consistency pass 2: airflow range via Configuration, multi-wavelength as in-development, ESP32/Pi CSV filename split, legacy sensor wording

← Older revision		Revision as of 19:47, 8 June 2026
Line 15:		Line 15:

	* '''Airflow:'''		* '''Airflow:'''
	** ~~Adjustable roughly between 25 and 500~~ mL/min (~~default 300 mL/min~~); the usable range narrows as the filter loads. With Auto Flow Control the device sets the rate automatically from the measured BC concentration.		** Default 300 mL/min, adjustable (see [[Configuration]] for the range). Higher flow improves signal but loads the filter faster; the usable range narrows as the filter loads. With Auto Flow Control the device sets the rate automatically from the measured BC concentration.
	** Higher airflow improves signal strength but loads the filter faster.		** Higher airflow improves signal strength but loads the filter faster.

Bcmwiki: Consistency pass: multi-wavelength in-development, bcmeter-pi link, anchor/Flask/V2 fixes, airflow & ATN clarifications

2026-06-08T18:43:41Z

Consistency pass: multi-wavelength in-development, bcmeter-pi link, anchor/Flask/V2 fixes, airflow & ATN clarifications

← Older revision		Revision as of 19:43, 8 June 2026
Line 15:		Line 15:

	* '''Airflow:'''		* '''Airflow:'''
	** ~~Minimum 40~~ mL/min~~, maximum 400~~ mL/min ~~(hardware-dependent~~).		** Adjustable roughly between 25 and 500 mL/min (default 300 mL/min); the usable range narrows as the filter loads. With Auto Flow Control the device sets the rate automatically from the measured BC concentration.
	** Higher airflow improves signal strength but loads the filter faster.		** Higher airflow improves signal strength but loads the filter faster.

Line 45:		Line 45:
	* At the default airflow in a typical urban environment (~500 ng/m³), a filter lasts approximately '''3–5 days'''.		* 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'''.		* 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~~.		* Filter status is derived from attenuation (ATN): measurements are fully quantitative up to about ATN 75 and degrade at higher loading; the device flags the filter for replacement around ATN 120. (The ATN value is not a simple percentage of light loss.)
	* The [[Configuration#Measurement Tab\|Airflow Reference table]] in Settings helps estimate filter lifetime for your conditions.		* The [[Configuration#Measurement Tab\|Airflow Reference table]] in Settings helps estimate filter lifetime for your conditions.

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)

New page

== 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.