Add airgradient (#32020)

source/_integrations/airgradient.markdown

@@ -0,0 +1,39 @@
+---
+title: Airgradient
+description: Instructions on how to setup Airgradient devices in Home Assistant.
+ha_category:
+  - Health
+  - Sensor
+ha_config_flow: true
+ha_release: 2024.6
+ha_iot_class: Local Polling
+ha_codeowners:
+  - '@airgradienthq'
+  - '@joostlek'
+ha_domain: airgradient
+ha_platforms:
+  - sensor
+ha_integration_type: integration
+ha_zeroconf: true
+---
+
+The Airgradient integration will fetch data from your [Airgradient devices](https://www.airgradient.com/).
+
+{% include integrations/config_flow.md %}
+
+## Available sensors
+
+The integration will fetch data from each device. The following sensors are supported:
+
+- Carbon dioxide
+- Humidity
+- Nitrogen index
+- PM0.03 count
+- PM1 density
+- PM2.5 density
+- PM10 density
+- Raw nitrogen
+- Raw total volatile organic compounds
+- Signal strength
+- Temperature
+- Total volatile organic compounds index