{ "synthetic": true, "format": "Generic teaching format, version 1; not a manufacturer export", "gas": "Hydrogen sulfide (H2S)", "unit": "ppm", "timezone": "UTC", "planned_window_start": "2026-01-15T09:00:00+00:00", "planned_window_end": "2026-01-15T09:20:00+00:00", "numeric_field_definition": "Mean for the entire half-open one-minute interval [start,end), accepted as valid within this teaching exercise. No concentration curve is supplied.", "missing_field_definition": "No measurement value supplied for this interval. The cause is unknown. Not zero.", "event_definition": "Independent event summary. Duration is recorded alarm-event duration, not proof of total exposure duration. Peak is a reported event maximum, not the unknown true atmospheric maximum.", "unknown_real_instrument_fields": [ "internal sampling frequency", "sensor response", "detection/reporting thresholds", "actual firmware", "actual calculation algorithm", "actual person and location" ], "exercise_date_is_fictional": true }