# Bad Air Days: The Effect of Air Stagnation during Pregnancy on Birth Outcomes and Infant Mortality in the U.S. and Mexico

> **NIH NIH R03** · TUFTS UNIVERSITY MEDFORD · 2020 · $78,000

## Abstract

Project Summary/Abstract
Despite the documented relationship between climate and extreme weather events, to date, there remain
important gaps in scientific knowledge regarding how and the extent to which human health may be damaged
by climate-related weather events, both directly and indirectly, domestically and internationally.
 We propose to identify air stagnation as a unique and critical environmental determinant of health and to
assess its effects on newborns. Air stagnation, characterized by low wind and absence of precipitation, can lead
to air pollution episodes and is expected to intensify and lengthen as a changing climate shifts global wind and
precipitation patterns. However, little is known about its implications for human health. We focus on birth
outcomes of newborns and infant mortality because evidence of the relationship between in-utero exposures to
environmental hazards and fetal health and infant mortality remains insufficient to infer causality, the modes of
exposure, sizes of the effects, and critical timings of the exposures.
 The analysis takes advantage of the unique and exogenous variation in daily air stagnation events and the
comprehensive natality and mortality datasets with geocoded residential locations from Michigan, Pennsylvania,
and Mexico collected for nearly a decade. These features allow us to precisely estimate the intensity of
exposures to air stagnation experienced by individual mothers over the terms of their pregnancies by trimester.
 Our preliminary evidence, based on the monthly occurrence of air stagnation events in Michigan, indicates
statistically and economically significant associations between air stagnation events during gestation and birth
outcomes. Given these findings, we hypothesize that air stagnation is a critical environmental determinant of
health, and we will assess its effects on newborns. We also hypothesize that there are important heterogeneities
in the effects of air stagnation across different climate regions and demographic characteristics.
 These hypotheses will be addressed by the following Specific Aims: (1) Construct air stagnation events
data at the daily level, which substantially refines the estimation of pollution exposure measures and expands
the coverage to include Pennsylvania and Mexico; (2) Determine the effects of in-utero exposure to air stagnation
on birth outcomes of newborns’ health and infant mortality; and (3) Determine the heterogeneity in the effects of
air stagnation between the U.S. and Mexico, and within the countries by socioeconomic status.
 The anticipated outcomes will help policy makers design successful mitigation and adaptation policies,
such as development of an alert warning system and identify and protect sensitive populations. In addition, it will
advance knowledge regarding health effects of climate change-related extreme weather events by providing
rigorous scientific evidence using real-time health, weather, geospatial, and exposure data.

## Key facts

- **NIH application ID:** 10058008
- **Project number:** 1R03ES030458-01A1
- **Recipient organization:** TUFTS UNIVERSITY MEDFORD
- **Principal Investigator:** Shinsuke Tanaka
- **Activity code:** R03 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $78,000
- **Award type:** 1
- **Project period:** 2020-09-11 → 2022-08-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10058008

## Citation

> US National Institutes of Health, RePORTER application 10058008, Bad Air Days: The Effect of Air Stagnation during Pregnancy on Birth Outcomes and Infant Mortality in the U.S. and Mexico (1R03ES030458-01A1). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10058008. Licensed CC0.

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