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fix: adopt 2024 EPA PM2.5 AQI breakpoints for cross-platform alignment #6273

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Merged
jamesarich merged 1 commit into from
Jul 15, 2026
Merged

fix: adopt 2024 EPA PM2.5 AQI breakpoints for cross-platform alignment #6273

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14 changes: 8 additions & 6 deletions core/model/src/commonMain/kotlin/org/meshtastic/core/model/util/AirQualityIndex.kt
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Original file line number Diff line number Diff line change
Expand Up @@ -84,15 +84,17 @@ object AirQualityIndex {
val aqiHigh: Int,
)

// Standard EPA PM2.5 (µg/m³) breakpoint table.
// Current (2024) EPA PM2.5 24-hour breakpoint table (AQS parameter 88101), µg/m³.
// Kept in lockstep with iOS (meshtastic/Meshtastic-Apple#2075) for cross-platform AQI alignment
// (meshtastic/design#54).
private val BREAKPOINTS =
listOf(
Breakpoint(0.0, 12.0, 0, 50),
Breakpoint(12.1, 35.4, 51, 100),
Breakpoint(0.0, 9.0, 0, 50),
Breakpoint(9.1, 35.4, 51, 100),
Breakpoint(35.5, 55.4, 101, 150),
Breakpoint(55.5, 150.4, 151, 200),
Breakpoint(150.5, 250.4, 201, 300),
Breakpoint(250.5, 500.4, 301, 500),
Breakpoint(55.5, 125.4, 151, 200),
Breakpoint(125.5, 225.4, 201, 300),
Breakpoint(225.5, 325.4, 301, 500),
)

/**
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23 changes: 15 additions & 8 deletions core/model/src/commonTest/kotlin/org/meshtastic/core/model/util/AirQualityIndexTest.kt
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Original file line number Diff line number Diff line change
Expand Up @@ -27,21 +27,28 @@ private const val EPSILON = 0.001

class AirQualityIndexTest {

// EPA PM2.5 breakpoint table reference values (concentration -> AQI).
// Current (2024) EPA PM2.5 24-hour breakpoint table reference values (concentration -> AQI).
@Test
fun pm25ToAqi_matches_epa_breakpoint_table() {
assertEquals(0, AirQualityIndex.pm25ToAqi(0.0))
assertEquals(50, AirQualityIndex.pm25ToAqi(12.0))
assertEquals(51, AirQualityIndex.pm25ToAqi(12.1))
assertEquals(50, AirQualityIndex.pm25ToAqi(9.0))
assertEquals(51, AirQualityIndex.pm25ToAqi(9.1))
assertEquals(100, AirQualityIndex.pm25ToAqi(35.4))
assertEquals(101, AirQualityIndex.pm25ToAqi(35.5))
assertEquals(150, AirQualityIndex.pm25ToAqi(55.4))
assertEquals(151, AirQualityIndex.pm25ToAqi(55.5))
assertEquals(200, AirQualityIndex.pm25ToAqi(150.4))
assertEquals(201, AirQualityIndex.pm25ToAqi(150.5))
assertEquals(300, AirQualityIndex.pm25ToAqi(250.4))
assertEquals(301, AirQualityIndex.pm25ToAqi(250.5))
assertEquals(500, AirQualityIndex.pm25ToAqi(500.4))
assertEquals(200, AirQualityIndex.pm25ToAqi(125.4))
assertEquals(201, AirQualityIndex.pm25ToAqi(125.5))
assertEquals(300, AirQualityIndex.pm25ToAqi(225.4))
assertEquals(301, AirQualityIndex.pm25ToAqi(225.5))
assertEquals(500, AirQualityIndex.pm25ToAqi(325.4))
}

// Regression for meshtastic/design#54: PM2.5 = 10 µg/m³ was "42, Good" on the legacy table;
// on the 2024 table it must be "53, Moderate", matching iOS (meshtastic/Meshtastic-Apple#2075).
@Test
fun pm25ToAqi_uses_2024_breakpoints_for_low_concentrations() {
assertEquals(53, AirQualityIndex.pm25ToAqi(10.0))
}

@Test
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