S2 Ep29: The true cost of emissions cheating

Episode Summary

Executive Summary: The episode examines Volkswagen’s emissions-cheating scandal as a natural experiment to measure how car pollution affects health. Hannes Schwandt explains that hidden diesel emissions increased ambient pollution and caused substantial harms, including lower birth weight, more low-birth-weight babies, and more childhood asthma. The findings suggest car pollution damages people across income groups, there may be no safe level, and stronger enforcement plus consumer awareness are key policy responses.

Main Topics: Volkswagen emissions scandal as a natural experiment (Priority: 5/5): The transcript explains how VW’s defeat devices created an unintended experiment: identical-looking cars produced very different pollution levels, allowing researchers to isolate causal effects of car exhaust on health. Measuring infant and child health impacts (Priority: 5/5): The paper focuses on birth outcomes and child health, finding lower birth weight, more low-birth-weight infants, and more asthma-related emergency visits in areas with more cheating diesel cars. Why car pollution is hard to study causally (Priority: 4/5): Schwandt lays out the main empirical problems in past research: residential sorting, avoidance behavior, and poor pollution measurement due to sparse monitors and noisy data. Who is most affected by car pollution (Priority: 4/5): Contrary to much prior literature, the strongest effects appear among more advantaged groups because cheating diesel cars were disproportionately purchased in higher-income, cleaner areas. No safe level of car pollution (Priority: 4/5): The results suggest effects are roughly linear, with similar health harms at low and high pollution levels, undermining policies that rely on pollution thresholds. Policy lessons: enforcement and consumer information (Priority: 5/5): The scandal highlights the importance of regulatory enforcement, better monitoring, and informing consumers so they can factor pollution into vehicle choices.

Key Arguments: The scandal provides a rare quasi-experimental setting because consumers did not know the cars were cheating, so they could not avoid exposure. Traditional pollution-health correlations are confounded by who lives where, who drives what, and poorly measured exposure. Cheating diesel cars increased real-world ambient pollution, especially PM2.5 and ozone, while gas-option versions of the same models did not. Even a small increase in cheating cars per thousand vehicles produced measurable health harms, implying large societal effects when scaled up. Low birth weight has long-term consequences beyond infancy, including worse test scores, lower wages, and poorer health later in life. Pollution harms were not limited to poor populations; richer, more educated mothers showed stronger estimated effects because they were more exposed. The evidence does not support a clear safe threshold for car pollution; incremental reductions appear beneficial even in cleaner areas. Stronger enforcement matters because regulation without enforcement can be gamed, as Volkswagen’s conduct demonstrated.

Data Points: Total cheating cars: around 600,000 - Volkswagen diesel cars with defeat devices rolled out in the U.S. between 2008 and 2015 Pollution intensity: up to 150 times as much NO2 as a normal gasoline car - Real-world emissions from cheating diesel engines compared with standard petrol cars Birth outcome impact: 38,000 babies - Estimated number of babies born with low birth weight due to the additional emissions-cheating cars Low-birth-weight definition: less than 2,500 grams - Medical cutoff used to define low birth weight Effect on low birth weight: 2% increase - For every additional cheating car per 1,000 cars Median county exposure: 1.6 cheating diesel cars per 1,000 cars - Typical county-level prevalence of cheating vehicles Emissions translation: one additional cheating car per 1,000 ≈ 10% increase in overall passenger car pollution - Based on the midpoint assumption that a cheating car pollutes about 100 regular cars Asthma effect: 8% increase - Increase in asthma emergency department visits for every additional cheating car per 1,000 cars Pollutants detected: PM2.5 and ozone increased - Ambient air pollution monitors showed rises in pollutants especially associated with diesel exhaust Study scope: infant, child health - Primary outcomes analyzed in the paper, with mortality at older ages noted as a future extension

Pivotal Quotes: "there is really no safe level of car pollution in particular" — Hannes Schwandt: Summarizing the paper’s finding that pollution-health effects appear roughly linear even at lower pollution levels "why would you regulate in the first place if you can't enforce it" — Hannes Schwandt: Arguing that enforcement capacity is essential, not just stronger rules "this emissions cheating scandal really provided us with a unique opportunity to solve this trio of empirical challenges" — Hannes Schwandt: Explaining why the VW scandal creates a credible natural experiment

Implications: The episode suggests car pollution causes broad, measurable health damage, including in relatively affluent areas, so enforcement, monitoring, and consumer transparency are as important as new regulation. It also supports faster movement toward cleaner vehicles, especially electrification.