How VisiblAir Cloud Portal Alerts Work

Cloud Portal alerts help you know when a sensor reading crosses an important threshold, when particulate readings may be affected by fog or humidity, or when a sensor stops reporting data.

Published: July 2026
Reading Time: 9 minutes
Category: How-To Guide

Where Alerts Are Configured

Alerts are configured per sensor in the VisiblAir Cloud Portal. Sign in, open the sensor configuration, and select the Alerts tab.

The main Enable Alerts checkbox controls the alert settings for that sensor. If it is off, metric threshold alerts, muted weekdays, PM pause options, and offline sensor alerts are not active for that sensor.

Per-Sensor Settings

Each sensor has its own alert configuration. Changing alert settings on one sensor does not change the settings on another sensor in the same account.

Metric Threshold Alerts

A metric threshold alert compares a new sensor reading to a value you choose. You can configure up to 10 metric rules per sensor.

Each rule has three parts:

  • Metric: the measurement to watch, such as CO2, PM2.5, temperature, humidity, pressure, VOC, NOX, noise, light, CH2O, supported gas readings, or wind speed where available.
  • Condition: whether the alert should trigger when the reading goes above or below the threshold.
  • Value: the threshold value for that metric.

Alerts are checked when the sensor sends a new sample to the cloud. If a reading crosses an enabled threshold, the portal records an alert event and sends email if recipients are configured.

Example: CO2 Ventilation Alert

To be notified when a room may need more ventilation, configure a rule such as:

  • Metric: CO2
  • Condition: above
  • Value: 1000

When a new sample reports CO2 above 1000 ppm, the sensor creates an alert event and sends email to the configured recipients, subject to the cool-off period.

Email Recipients

Alert emails can be sent to the account email, to additional visible recipients, and to BCC recipients.

  • Use Send alerts to account e-mail to notify the sensor owner's account address.
  • Use Send alerts to other e-mails to add a comma-separated list of additional recipients.
  • Use the BCC field when recipients should receive the alert without being visible to other recipients.

Use valid email addresses and separate multiple addresses with commas. If an invalid recipient is entered, that address may be skipped.

Cool-Off Period

The cool-off period limits repeated emails for the same alert condition: the same sensor, metric, condition, and threshold value. It is not one shared timer for every alert on the sensor. The default is 60 minutes.

For example, if CO2 remains above 1000 ppm for several samples, the portal does not send a new email for every sample. It waits until the CO2 above 1000 ppm cool-off period has passed before sending another email for that same alert condition.

Other alert conditions have their own cool-off timing. If PM2.5 above threshold sends an alert at 2:00 AM, CO2 above threshold can still send an alert at 3:00 AM. If PM2.5 is still above the same threshold at 3:30 AM, it can send again because more than 60 minutes have passed since the PM2.5 alert. The CO2 alert at 3:00 AM does not reset the PM2.5 cool-off timer.

Changing the metric, the above/below condition, or the threshold value makes it a different alert condition for cool-off purposes.

Set a longer cool-off period for slow-moving situations where repeated notifications would not be useful. Set a shorter cool-off period when faster follow-up is needed.

Tier 2 Persistent Alerts

Tier 2 alerts are follow-up notifications for conditions that remain active after an initial threshold alert. They are useful when the first alert can go to the day-to-day contact, while a persistent issue should notify another person or escalation list.

When a metric threshold alert first triggers, the portal starts a Tier 2 watch window for that same sensor, metric, condition, and threshold value. At the end of that window, the system checks recent samples. If the condition was still true for most samples in the window, it sends a Tier 2 email and records a persistent alert event.

Use these fields together:

  • Send alert if a previous alert condition is valid for up to the defined period: turns on Tier 2 persistent alerts.
  • To: visible Tier 2 recipients, entered as a comma-separated list.
  • BCC: private Tier 2 recipients, entered as a comma-separated list.
  • Time period: the watch window in minutes. If the value is missing or invalid, the system uses 15 minutes.

Current portal behavior expects both the Tier 2 To and BCC fields to be filled before Tier 2 emails are sent. If you do not need private recipients, use an appropriate operational address in the BCC field so the Tier 2 configuration is complete.

Tier 2 applies to metric threshold alerts, not to offline sensor alerts. It follows the same threshold condition that created the initial alert. It is available for the main air-quality and environmental metrics, but not currently for wind speed or PM4.0 persistent-alert emails.

Example: Escalating Persistent CO2

A classroom sensor can send the first CO2 alert to the facility contact when CO2 goes above 1000 ppm. Tier 2 can then notify a facilities manager if CO2 remains above 1000 ppm through a 30-minute watch window.

  • Metric alert: CO2 above 1000
  • Primary recipients: the account email or room operator
  • Tier 2 time period: 30 minutes
  • Tier 2 recipients: the escalation contact or team mailbox

Muted Full Days

Muted weekdays suppress threshold alert checks for full calendar days. Muted days use the sensor timezone shown in the portal. If the sensor timezone is missing or invalid, the system falls back to America/Toronto.

This is useful for predictable periods when notifications are not wanted. For example, a school may mute alerts on Saturday and Sunday, while keeping weekday alerts active.

PM Fog And Humidity Pauses

Outdoor particulate matter readings can be affected by fog or very high humidity. The Alerts tab includes options to pause PM alerts when those conditions are likely.

  • Pause PM alerts if fog is detected: uses temperature and humidity to estimate likely fog conditions.
  • Pause PM alerts if humidity goes above: pauses PM alerts when relative humidity is above the percentage you enter.

These pauses apply to PM metrics only. Other alert metrics, such as CO2 or temperature, continue to be evaluated.

Offline Sensor Alerts

Offline alerts are separate from metric threshold alerts. Enable Alerts when sensor stops sending data for 15 minutes when you want to be notified if a sensor has not reported recently.

The offline alert processor runs on a schedule, so an offline email may not arrive exactly 15 minutes after the last sample. In production, the check currently runs hourly. Treat the 15-minute setting as the offline detection threshold, not as an exact email delivery time.

Offline emails are sent to the account owner and any configured additional recipients. Duplicate offline messages are suppressed for a period so a sensor that stays offline does not send constant emails.

Example: Offline Sensor Alert

For an outdoor sensor installed at a remote site, turn on Enable Alerts, then turn on Alerts when sensor stops sending data for 15 minutes. If the sensor stops reporting, the next scheduled offline check can email the configured recipients.

Troubleshooting

No Email Was Received

  • Confirm Enable Alerts is on for the sensor.
  • Confirm at least one recipient option is enabled.
  • Check that recipient addresses are valid and comma-separated.
  • For Tier 2 alerts, make sure both the Tier 2 To and BCC fields are filled.
  • Check spam or quarantine folders for messages from VisiblAir.
  • Remember that cool-off periods suppress repeated emails for the same alert.

An Alert Did Not Trigger

  • Confirm the metric rule is not set to Disabled.
  • Confirm the condition and threshold value match what you intended.
  • Check whether the sensor sent a new sample after the rule was saved.
  • Check whether the current day is muted for that sensor timezone.
  • For PM alerts, check whether fog or high-humidity pause options are active.
  • For Tier 2 alerts, confirm the original metric threshold alert triggered first and that the condition remained active during the watch window.

An Alert Repeated

Repeated alerts are expected after the cool-off period expires if the same condition is still true. Increase the cool-off period if you want fewer repeat notifications.

Practical Starting Point

For most indoor CO2 use cases, start with one CO2 threshold, send alerts to the account email, and keep the default 60-minute cool-off period. Add extra recipients or muted days only when the basic alert flow is working as expected.