PM10 level crossed threshold

The PM10 level crossed threshold trigger fires when the PM10 (particulate matter 10 micrometers or smaller) reading on one or more air quality sensors crosses a specific level. PM10 includes coarser particles like dust, pollen, and mold spores that irritate the nose, throat, and airways. Levels tend to spike during construction work, dry windy days, and seasonal pollen peaks.

Get a heads-up on your phone the moment outdoor PM10 crosses 50, so you know to keep the windows shut on a high-pollen day. Or have your smart windows close automatically when a dust storm rolls in. This trigger is especially helpful during allergy season, letting your home shield you from airborne irritants before they become a problem.

Using this trigger from the user interface

If you prefer building automations visually, Home Assistant walks you through this trigger step by step. You pick what to watch, tweak a few options, and save. No YAML knowledge required.

To use this trigger in an automation:

1. Go to Settings > Automations & scenes.
2. Open an existing automation, or select Create automation > Create new automation.
3. In the When section, select Add trigger.
4. Select what you want to monitor. Under By target (see Targets), pick the area your air quality sensor is in (like your living room or bedroom). You can also select a floor, a device, a specific entity, or a label.
5. From the triggers shown for that target, select PM10 level crossed threshold.
6. Under Threshold type, set the PM10 level the reading must cross for the trigger to fire.
7. Under Trigger when (see Behavior), pick Any, First, or Last to control how multiple targets interact.
8. Under For at least, set how long the level must stay past the threshold before the trigger fires. Leave at the default to fire immediately.
9. Select Save.

Options in the UI

Using this trigger in YAML

If you work directly in YAML, or you want to know exactly what Home Assistant does under the hood, this section has the technical reference. It lists the field names you use in YAML, their types, and which ones are required.

In YAML, refer to this trigger as air_quality.pm10_crossed_threshold. A basic example looks like this:

trigger: air_quality.pm10_crossed_threshold
target:
  entity_id: sensor.patio_pm10
options:
  threshold: 50
  behavior: any

This fires whenever the patio PM10 sensor crosses 50 in either direction.

Options in YAML

YAML sometimes provides additional options for more complex use cases that are not available through the UI.

Targets

This trigger supports targets. A target tells Home Assistant what the trigger should watch. You can point it at a single entityAn entity represents a sensor, actor, or function in Home Assistant. Entities are used to monitor physical properties or to control other entities. An entity is usually part of a device or a service. [Learn more], a device, an area, a floor, or a label, and Home Assistant watches every matching air_quality entity behind that target.

• Entity: one specific air_quality entity, such as air_quality.living_room.
• Device: every air_quality entity that belongs to a device.
• Area: every air_quality entity in a room or area.
• Floor: every air_quality entity on a floor.
• Label: every air_quality entity that shares a label.

You can also mix target types in one trigger. For example, combine a specific entity with an area to watch both at once.

Behavior with multiple targets

When you target more than one entity (or select an area, floor, or label that contains several), the Trigger when option controls how the trigger responds:

• Any (default): the trigger fires every time any one of the targeted entities transitions. For example, if you monitor three motion sensors in the living room and someone walks past sensor 1, the automation fires. When they walk past sensor 2 a moment later, it fires again. Every individual event counts.
• First: the trigger fires only on the first transition in the targeted group, then waits until all targeted entities have reset before it fires again. For example, if you monitor the same three motion sensors, the automation fires when the first one picks up movement (someone entered the room). The other two firing afterward are ignored, so you get one notification per “someone walked in” event instead of three.
• Last: the trigger fires only after the last targeted entity in the group has fired, meaning all of them are now in the expected state. For example, if you monitor the lights in the living room, bedroom, and hallway, the automation fires only once all three have turned off. This is useful for scenarios like “start the robot vacuum only after every light on the floor is off,” so you know the room is truly empty.

Good to know

• The trigger fires on any crossing, up or down. If you only want one direction, add a condition that checks whether the current PM10 level is above or below your threshold.
• The WHO guideline for 24-hour average PM10 exposure is 45. A threshold between 45 and 100 is a reasonable starting point depending on your local environment.
• Pair this trigger with PM10 level changed if you also want to track smaller fluctuations between crossings.

Try it yourself

Ready to test this? Go to Settings > Automations & scenes, create a new automation, and add this trigger. Save the automation, then change the state of the targeted entity to watch the trigger fire on your actual entitiesAn entity represents a sensor, actor, or function in Home Assistant. Entities are used to monitor physical properties or to control other entities. An entity is usually part of a device or a service. [Learn more].

More examples

Real scenarios where this trigger fires in automations and scripts. Copy any example and adapt it to your setup.

Automation: get a pollen season heads-up on your phone

Allergy season is tough enough without guessing whether the air outside is safe. This automation sends a notification to your phone when outdoor PM10 crosses 50, so you know to keep the windows shut and stay comfortable indoors.

• Trigger: PM10 level crossed threshold
• Target: Patio PM10 sensor
• Threshold type: 50
• Trigger when: Any
• Condition: PM10 is above 50
• Action: Notify mobile app

alias: "PM10 pollen season alert"
triggers:
  - trigger: air_quality.pm10_crossed_threshold
    target:
      entity_id: sensor.patio_pm10
    options:
      threshold: 50
      behavior: any
conditions:
  - condition: numeric_state
    entity_id: sensor.patio_pm10
    above: 50
actions:
  - action: notify.mobile_app_phone
    data:
      title: "High PM10 outside"
      message: >
        Outdoor PM10 crossed 50.
        Consider keeping windows closed.

Still stuck?

The Home Assistant community is quick to help: join Discord for real-time chat, post on the community forum with the trigger you’re using and what you expected to happen, or share on our subreddit /r/homeassistant.

Related triggers

These triggers work well alongside this one:

• PM10 level changed - Triggers after one or more PM10 levels change.