diff --git a/homeassistant/components/homekit/type_sensors.py b/homeassistant/components/homekit/type_sensors.py
index 7e9b4cbbb31..e877ffff07a 100644
--- a/homeassistant/components/homekit/type_sensors.py
+++ b/homeassistant/components/homekit/type_sensors.py
@@ -56,7 +56,6 @@ from .util import (
     convert_to_float,
     density_to_air_quality,
     density_to_air_quality_pm10,
-    density_to_air_quality_pm25,
     temperature_to_homekit,
 )
 
@@ -239,7 +238,7 @@ class PM25Sensor(AirQualitySensor):
         if self.char_density.value != density:
             self.char_density.set_value(density)
             _LOGGER.debug("%s: Set density to %d", self.entity_id, density)
-        air_quality = density_to_air_quality_pm25(density)
+        air_quality = density_to_air_quality(density)
         if self.char_quality.value != air_quality:
             self.char_quality.set_value(air_quality)
             _LOGGER.debug("%s: Set air_quality to %d", self.entity_id, air_quality)
diff --git a/homeassistant/components/homekit/util.py b/homeassistant/components/homekit/util.py
index 34df1008e76..b7af7d516dd 100644
--- a/homeassistant/components/homekit/util.py
+++ b/homeassistant/components/homekit/util.py
@@ -400,16 +400,16 @@ def temperature_to_states(temperature: float | int, unit: str) -> float:
 
 
 def density_to_air_quality(density: float) -> int:
-    """Map PM2.5 density to HomeKit AirQuality level."""
-    if density <= 35:
+    """Map PM2.5 µg/m3 density to HomeKit AirQuality level."""
+    if density <= 12:  # US AQI 0-50 (HomeKit: Excellent)
         return 1
-    if density <= 75:
+    if density <= 35.4:  # US AQI 51-100 (HomeKit: Good)
         return 2
-    if density <= 115:
+    if density <= 55.4:  # US AQI 101-150 (HomeKit: Fair)
         return 3
-    if density <= 150:
+    if density <= 150.4:  # US AQI 151-200 (HomeKit: Inferior)
         return 4
-    return 5
+    return 5  # US AQI 201+ (HomeKit: Poor)
 
 
 def density_to_air_quality_pm10(density: float) -> int:
@@ -425,19 +425,6 @@ def density_to_air_quality_pm10(density: float) -> int:
     return 5
 
 
-def density_to_air_quality_pm25(density: float) -> int:
-    """Map PM2.5 density to HomeKit AirQuality level."""
-    if density <= 25:
-        return 1
-    if density <= 50:
-        return 2
-    if density <= 100:
-        return 3
-    if density <= 300:
-        return 4
-    return 5
-
-
 def get_persist_filename_for_entry_id(entry_id: str) -> str:
     """Determine the filename of the homekit state file."""
     return f"{DOMAIN}.{entry_id}.state"
diff --git a/tests/components/homekit/test_type_sensors.py b/tests/components/homekit/test_type_sensors.py
index 75069ce9467..b916d447d12 100644
--- a/tests/components/homekit/test_type_sensors.py
+++ b/tests/components/homekit/test_type_sensors.py
@@ -126,7 +126,7 @@ async def test_air_quality(hass, hk_driver):
     hass.states.async_set(entity_id, "34")
     await hass.async_block_till_done()
     assert acc.char_density.value == 34
-    assert acc.char_quality.value == 1
+    assert acc.char_quality.value == 2
 
     hass.states.async_set(entity_id, "200")
     await hass.async_block_till_done()
@@ -205,7 +205,7 @@ async def test_pm25(hass, hk_driver):
     hass.states.async_set(entity_id, "23")
     await hass.async_block_till_done()
     assert acc.char_density.value == 23
-    assert acc.char_quality.value == 1
+    assert acc.char_quality.value == 2
 
     hass.states.async_set(entity_id, "34")
     await hass.async_block_till_done()
@@ -215,12 +215,12 @@ async def test_pm25(hass, hk_driver):
     hass.states.async_set(entity_id, "90")
     await hass.async_block_till_done()
     assert acc.char_density.value == 90
-    assert acc.char_quality.value == 3
+    assert acc.char_quality.value == 4
 
     hass.states.async_set(entity_id, "200")
     await hass.async_block_till_done()
     assert acc.char_density.value == 200
-    assert acc.char_quality.value == 4
+    assert acc.char_quality.value == 5
 
     hass.states.async_set(entity_id, "400")
     await hass.async_block_till_done()
diff --git a/tests/components/homekit/test_util.py b/tests/components/homekit/test_util.py
index 3dd30af2056..f3811ce34c5 100644
--- a/tests/components/homekit/test_util.py
+++ b/tests/components/homekit/test_util.py
@@ -224,12 +224,15 @@ def test_temperature_to_states():
 def test_density_to_air_quality():
     """Test map PM2.5 density to HomeKit AirQuality level."""
     assert density_to_air_quality(0) == 1
-    assert density_to_air_quality(35) == 1
-    assert density_to_air_quality(35.1) == 2
-    assert density_to_air_quality(75) == 2
-    assert density_to_air_quality(115) == 3
-    assert density_to_air_quality(150) == 4
-    assert density_to_air_quality(300) == 5
+    assert density_to_air_quality(12) == 1
+    assert density_to_air_quality(12.1) == 2
+    assert density_to_air_quality(35.4) == 2
+    assert density_to_air_quality(35.5) == 3
+    assert density_to_air_quality(55.4) == 3
+    assert density_to_air_quality(55.5) == 4
+    assert density_to_air_quality(150.4) == 4
+    assert density_to_air_quality(150.5) == 5
+    assert density_to_air_quality(200) == 5
 
 
 async def test_async_show_setup_msg(hass, hk_driver, mock_get_source_ip):