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How Polluted Is Beijing's Air This Hour?

From the dew point, temperature, pressure, wind, snow and rain, how much fine particulate matter is in Beijing's air? Weather explains a lot of pollution, and knowing how much helps a city tell weather from emissions.

Use caseClimatePredictionModel evaluation

The table

Five years of hourly weather readings at the US embassy in Beijing, with the PM2.5 concentration for each hour. It's in Welt's research catalogue as Beijing PM2.5 Air Quality and Weather, 43,824 rows by 13 columns, licensed CC BY 4.0. The catalogue measures its signal at 0.57. At 43,824 rows and 12 features the table is larger than the model limits allow, so the walkthrough evaluates and fits on a seeded sample of 8,000 rows. TabICLv2 and Kumo Tabular Medium compete.

Walkthrough

  1. Load it from the catalogue

    Find the table, read its recorded target and print the column names.

    import pandas as pd
    from welt import Client
    
    with Client() as client:
        item = client.research_datasets(q="Beijing PM2.5", limit=1)["items"][0]
        info = client.research_dataset(item["id"])
        data = client.load_research_dataset(item["id"])
    
    target = info["targets"][0]
    target = target["name"] if isinstance(target, dict) else target
    print([column["name"] for column in info["schema"]], target)
  2. Pick the rows

    Set aside 20 rows to predict at the end. The models learn from a seeded sample of 8,000 of the rest, the most this table's width allows.

    known = data.dropna(subset=[target])
    new_rows = known.sample(20, random_state=1)
    table = known.drop(new_rows.index).sample(8000, random_state=7)
  3. Compare the models and predict

    The models compete on the same folds against a simple guess, then the top-ranked one is fitted on the whole table. RMSE and MAE are average errors in the target's own units, so lower is better. The last table puts each prediction next to the real answer.

    with Client() as client:
        evaluation = client.evaluate(table, target, task="regression", seed=7,
                                     models=["tabicl-v2", "kumo-medium"])
        model = evaluation.fit()
    
    print(evaluation.summary()[["name", "rank", "rmse_mean", "mae_mean"]])
    features = new_rows.drop(columns=target)
    print(pd.DataFrame({"actual": new_rows[target].values, "predicted": model.predict(features)}))

What you get

PM2.5 per hourAn estimate from the weather alone.
Weather or emissionsHours far above the estimate point to a source, not the weather.
A clear comparisonThe leaderboard shows how much weather explains.

Try it

Use Open with to run the research datasets notebook in Colab, Kaggle or Jupyter and search for "Beijing PM2.5", or run the code above after pip install "welt-client[parquet]".