> ## Documentation Index > Fetch the complete documentation index at: https://offthepace.mintlify.site/llms.txt > Use this file to discover all available pages before exploring further. # int_dirty_air_tax_component > One row per lap. Part of the [Physics](/transform/families/physics) family. > For the conceptual foundation, read [Int Dirty Air Tax Component](/decomposition/methodology). One row per lap. Cost of driving in dirty air (turbulent wake) following another car. Uses prior-lap dirty-air intensity to establish causality: current lap slowdown → prior lap's position. Avoids reverse causality. Seconds lost = θ\_air × dirty\_air\_intensity\_lag1, capped \[0, 5.0] seconds. θ\_air IS FITTED FROM THE DATA, not configured: it is the OLS slope of partial residual on the lagged dirty-air bit over the full two-arm calibration panel (treated and untreated laps). Before 08q (2026-09-21) the panel was filtered to `dirty_air_share_lag1 > 0`, which left the binary regressor constant and unidentified, so θ\_air silently fell through a COALESCE to the literal 0.5 s/lap on every build and dirty\_air\_tax\_s was 0.5 on every dirty-air lap and 0.0 otherwise. Measured on the v12 substrate the fitted value is +0.1310 s/lap \[95% CI +0.1144, +0.1476] over 123,993 laps — the shipped 0.5 was 3.8x too high. The COALESCE literal is now that measured estimate and serves only as a degenerate-panel guard. A global pooled θ is used deliberately; per-season θ runs +0.418 (2018) to -0.011 (2024) and is not distinguishable from zero on 2021 and 2024, which is an open ruling for any fan-facing surface that reports per-driver seconds (see work/08-foundations-repair.md section 08q). ## Lineage ```mermaid theme={null} flowchart LR int_event_corrections --> int_dirty_air_tax_component int_field_pace_curve --> int_dirty_air_tax_component int_lap_air_state --> int_dirty_air_tax_component int_lap_fuel_state --> int_dirty_air_tax_component int_stint_geometry --> int_dirty_air_tax_component int_track_evolution --> int_dirty_air_tax_component int_dirty_air_tax_component --> fct_stint_features int_dirty_air_tax_component --> int_lap_residual_decomposed style int_dirty_air_tax_component fill:#e40404,stroke:#e40404,color:#fff ``` ## Overview | Property | Value | | ----------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | Layer | `intermediate` | | Family | [Physics](/transform/families/physics) | | Contract enforced | No | | Tags | `causal_decomposition`, `dirty_air` | | Upstream | [`int_lap_fuel_state`](./int_lap_fuel_state), [`int_field_pace_curve`](./int_field_pace_curve), [`int_stint_geometry`](./int_stint_geometry), [`int_lap_air_state`](./int_lap_air_state), [`int_event_corrections`](./int_event_corrections), [`int_track_evolution`](./int_track_evolution) | **11 tests** [guard](/transform/ci/overview) this model - 10 generic, 1 singular. ## Columns | Column | Type | Nullable | Tests | Description | | --------------------------------- | ---- | -------- | -------------------------------------------------------------------------------------------------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | `lap_id` | | Yes | [`not_null`](/transform/ci/structural), [`unique`](/transform/ci/structural) | PK, FK to stg\_laps | | `dirty_air_intensity_lag1` | | Yes | [`not_null`](/transform/ci/structural) | One-lap-lagged dirty-air intensity from int\_lap\_air\_state | | `dirty_air_tax_s` | | Yes | [`not_null`](/transform/ci/structural), [`expect_column_values_to_be_between`](/transform/ci/range-and-domain) | Per-lap dirty-air slowdown in seconds. θ\_air × dirty\_air\_intensity\_lag1. Positive (slower cost). Bounded \[0, 5.0]. θ\_air is estimated from the two-arm calibration panel, not defaulted (08q). Because dirty\_air\_intensity\_lag1 is one bit per lap, this column still takes two values per build — 0.0 on a clean-air lap and θ\_air on a dirty-air lap — but θ\_air is now the fitted +0.1310 s/lap rather than the unfitted 0.5 literal it was through v12. A dose-response on the measured gap (int\_lap\_air\_state.min\_gap\_s / stg\_telemetry\_position.distance\_to\_ahead\_m) is the standing follow-up; removing the treated-arm filter is the identification fix, not the measurement fix. | | `dirty_air_tax_se_s` | | Yes | [`not_null`](/transform/ci/structural) | Standard error of the tax estimate via propagation | | `tax_calibration_confidence` | | Yes | [`not_null`](/transform/ci/structural), [`expect_column_values_to_be_between`](/transform/ci/range-and-domain) | Confidence in the tax \[0, 1], as n / (n + 500) over the calibration sample n. Since 08q restored both arms to that panel, n is the full 123,993-lap panel rather than the 28,523 treated laps it was through v12, so this reads \~0.996 rather than \~0.983. It measures calibration SAMPLE SIZE ONLY and is not a statement about whether θ\_air is distinguishable from zero in a given season — it is near 1.0 on every season including 2021 and 2024, where the per-season estimate straddles zero. | | `cumulative_dirty_air_tax_race_s` | | Yes | [`not_null`](/transform/ci/structural) | Running race-cumulative sum of per-lap dirty-air tax for each driver | | `dirtiest_air_lap_in_race_flag` | | Yes | [`not_null`](/transform/ci/structural) | TRUE on the lap where this driver's per-lap tax is at its maximum in the race |