# Reviewed air-analysis verification

## Reviewed change

The existing air-analysis.py and all prior outputs were preserved. air-analysis-reviewed.py was created with one presentation-only change: the report heading date range is derived from the validated input start and end timestamps. The calculation, at-least-18-valid-hours completeness rule, plot construction, and CSV fields were not changed.

The reviewed script differs from air-analysis.py in exactly one line: the report heading template.

## Script integrity

- SHA-256 before baseline run: 75823855828de9a934f1a0bf7f5b5b8f3569ed8138841f7694e59c87e5b64804
- SHA-256 after baseline run: 75823855828de9a934f1a0bf7f5b5b8f3569ed8138841f7694e59c87e5b64804
- SHA-256 after updated run: 75823855828de9a934f1a0bf7f5b5b8f3569ed8138841f7694e59c87e5b64804
- Unchanged across both runs: True

## Report headings verified

- Baseline report: Aotizhongxin PM2.5 analysis, 2016-01-01 through 2016-01-07
- Updated report: Aotizhongxin PM2.5 analysis, 2016-01-01 through 2016-01-14

## CSV equivalence verified

- air-daily-baseline.csv equals air-daily-v1.csv in every field: True
- Rows compared for baseline: 7
- air-daily-updated.csv equals air-daily-v2.csv in every field: True
- Rows compared for updated analysis: 14

Equality was checked after reopening the CSV files, with identical column order, data types, values, and missing-value positions required.