Table 3.

Comparing OLS and RD estimates of PM's impact on health outcomes

Outcome	[1]	[2]	[3]
Life expectancy at birth, y	−0.27*** (0.09)	−0.86* (0.51)	−0.64*** (0.22)
Cardiorespiratory (per 100,000, log)	0.02*** (0.01)	0.11* (0.06)	0.08*** (0.03)
Estimation method	OLS	IV	IV
RD type		Polynomial	LLR

In column [1], we report OLS estimates of the association between PM₁₀ and the listed outcome. In column [2], we report the 2SLS IV estimates using north of the Huai River as the IV and a cubic polynomial in degrees latitude from the Huai River interacted with a north dummy variable. In column [3], we estimate the impact of PM₁₀ on the listed outcomes using local linear regression (LLR), treating distance from the Huai River as the forcing variable and PM₁₀ as the treatment variable, with the Huai River representing a “fuzzy” discontinuity in the level of PM₁₀ exposure. Results are reported in terms of the impact of an additional 10 μg/m³ long-term PM₁₀ exposure. Results in columns [1] and [2] are based on the full sample (n = 154) and include the covariates listed in SI Appendix, Table S1. Column [3] is based on the bandwidth selection method proposed by Imbens and Kalyanaraman (14) with a triangular kernel.

^*Significant at 10%.

^***Significant at 1%.