diff --git a/src/Span.h b/src/Span.h
index 1d3b922..571d92e 100644
--- a/src/Span.h
+++ b/src/Span.h
@@ -477,15 +477,15 @@ namespace Characteristic {
CREATE_CHAR(boolean,MotionDetected,false,0,1,NOT_DETECTED,DETECTED); // indicates if motion is detected
CREATE_CHAR(boolean,Mute,false,0,1,OFF,ON); // not used
CREATE_CHAR(const char *,Name,"unnamed",0,1); // default name of a Service used only during initial pairing
- CREATE_CHAR(double,NitrogenDioxideDensity,0,0,1000); // measured in micrograms/m3
+ CREATE_CHAR(double,NitrogenDioxideDensity,0,0,1000); // measured in µg/m3
CREATE_CHAR(boolean,ObstructionDetected,false,0,1,NOT_DETECTED,DETECTED); // indicates if obstruction is detected
- CREATE_CHAR(double,PM25Density,0,0,1000); // 2.5-micron particulate density, measured in micrograms/m3
+ CREATE_CHAR(double,PM25Density,0,0,1000); // 2.5-micron particulate density, measured in µg/m3
CREATE_CHAR(uint8_t,OccupancyDetected,0,0,1,NOT_DETECTED,DETECTED); // indicates if occupanccy is detected
CREATE_CHAR(boolean,OutletInUse,false,0,1,NOT_IN_USE,IN_USE); // indicates if an appliance or light is plugged into the outlet, regardless of whether on or off
CREATE_CHAR(boolean,On,false,0,1,OFF,ON); // indicates if the Service is active/on
- CREATE_CHAR(double,OzoneDensity,0,0,1000); // measured in micrograms/m3
+ CREATE_CHAR(double,OzoneDensity,0,0,1000); // measured in µg/m3
CREATE_CHAR(uint8_t,PictureMode,0,0,13);
- CREATE_CHAR(double,PM10Density,0,0,1000); // 10-micron particulate density, measured in micrograms/m3
+ CREATE_CHAR(double,PM10Density,0,0,1000); // 10-micron particulate density, measured in µg/m3
CREATE_CHAR(uint8_t,PositionState,2,0,2,GOING_TO_MINIMUM,GOING_TO_MAXIMUM,STOPPED); // deprecated
CREATE_CHAR(uint8_t,PowerModeSelection,0,0,1);
CREATE_CHAR(uint8_t,ProgramMode,0,0,2,NONE,SCHEDULED,SCHEDULE_OVERRIDEN);
diff --git a/tools/test.md b/tools/test.md
index 016694f..85b4f8e 100644
--- a/tools/test.md
+++ b/tools/test.md
@@ -27,11 +27,11 @@
| Characteristic | UUID | Format | Perms | Min | Max | Defaults | Notes |
|---|
| AirQuality | 95 | uint8 | PR+EV | 0 | 5 | - UNKNOWN (0)
- EXCELLENT (1)
- GOOD (2)
- FAIR (3)
- INFERIOR (4)
- POOR (5)
| a subjective description |
| Name | 23 | string | PR | - | - | "unnamed" | default name of a Service used only during initial pairing |
-| OzoneDensity | C3 | float | PR+EV | 0 | 1000 | 0 | measured in micrograms/m3 |
-| NitrogenDioxideDensity | C4 | float | PR+EV | 0 | 1000 | 0 | measured in micrograms/m3 |
+| OzoneDensity | C3 | float | PR+EV | 0 | 1000 | 0 | measured in µg/m3 |
+| NitrogenDioxideDensity | C4 | float | PR+EV | 0 | 1000 | 0 | measured in µg/m3 |
| SulphurDioxideDensity | C5 | float | PR+EV | 0 | 1000 | 0 | |
-| PM25Density | C6 | float | PR+EV | 0 | 1000 | 0 | 2.5-micron particulate density, measured in micrograms/m3 |
-| PM10Density | C7 | float | PR+EV | 0 | 1000 | 0 | 10-micron particulate density, measured in micrograms/m3 |
+| PM25Density | C6 | float | PR+EV | 0 | 1000 | 0 | 2.5-micron particulate density, measured in µg/m3 |
+| PM10Density | C7 | float | PR+EV | 0 | 1000 | 0 | 10-micron particulate density, measured in µg/m3 |
| VOCDensity | C8 | float | PR+EV | 0 | 1000 | 0 | |
| StatusActive | 75 | bool | PR+EV | 0 | 1 | true | |
| StatusFault | 77 | uint8 | PR+EV | 0 | 1 | | |