Bui, L. T., Shadbegian, R., Marquez, A., Klemick, H., & Guignet, D. (2022). Does short-term, airborne lead exposure during pregnancy affect birth outcomes? Quasi-experimental evidence from NASCAR’s deleading policy. Environment international, 166, 107354.
Can the Social Safety Net catch lead? The moderating effect of WIC on prenatal lead exposure (JMP)
Lead remains a persistent public health concern despite decades of regulatory efforts to reduce exposure. Prenatal exposure is particularly concerning, as lead can cross the placental barrier and impact fetal development. Medical evidence suggests that nutrition can reduce lead absorption in the body. Despite this, causal evidence on whether access to nutritional support can translate this biological mechanism into an effective policy response is limited. I examine this relationship by linking restricted North Carolina birth certificate data to lead-emitting Toxic Release Inventory (TRI) facilities and clinics administering benefits for the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC). I exploit variation in TRI openings as shocks to prenatal lead exposure and implement a triple-differences design to test whether these effects vary with geographic proximity to WIC. I find that TRI openings adversely affect infant health among pregnancies near polluting facilities, with larger effects surrounding higher-emitting facilities. Triple-differences estimates show that proximity to WIC substantially attenuates the adverse effects of a TRI opening, particularly the increase in low birth weight, suggesting that pregnancies with greater geographic access to nutritional support are less sensitive to shocks in lead exposure. These differences are particularly pronounced among nonwhite mothers and mothers utilizing Medicaid, populations supported by the social safety net and disproportionately exposed to environmental hazards. Together, these findings suggest that nutritional support may provide a complementary policy lever for mitigating the health consequences of environmental toxins, particularly among disadvantaged populations.
Cumulative impacts of prenatal and early childhood lead exposure and access to SNAP (joint with Dr. Nicholas Sanders)
Various nutrition-based social programs may be differentially effective when insulating individuals from exposure to pollution. In addition to evidence that nutrition mitigates lead absorption, there is also evidence that lead absorption is diminished when ingested with food (ASTDR 2020). This begs the question - is it the nutrients that matter or simply the calories? SNAP is a prominent avenue in which families receive access to food security. in a typical year, SNAP serves about 20 million children in the country – approximately one out of every four (Center on Budget and Policy Priorities 2016). There is a consensus among the SNAP literature that SNAP participation reduces food insecurity and increases total food spending, though results on the effect of program participation on food quality are often null or extremely modest. We combine spatial and temporal variation in geographic access to SNAP authorized retailers with spatial and temporal variation in lead exposure via the openings and closings of lead-emitting Toxic Release Inventory (TRI) facilities. We find that birth outcomes among pregnancies in close proximity to SNAP-authorized retailers are better insulated against shocks to lead exposure, particularly through TRI openings. We then turn to elementary education data to examine the cumulative effect of childhood lead on academic achievement, and the extent to which this may be mitigated by access to public programs such as SNAP.
The stock and flow of lead exposure: Can remediation keep up?