# Trimester-Specific Variation in Air Quality and Risk for Autism Spectrum Disorder: A Natural Experiment

> **NIH NIH R01** · JOHNS HOPKINS UNIVERSITY · 2020 · $600,420

## Abstract

Abstract
Autism spectrum disorder (ASD) is a set of neurodevelopmental disorders marked by impaired social
communication and interaction, and repetitive, restricted behaviors and interests. Studies from the U.S. and
Europe suggest that prenatal air pollution exposure (PNAPE), and exposure during early infancy, increase risk
for ASD. PNAPE-associated risk for ASD has not yet been well studied in areas with very high levels of air
pollution around the world. This proposal capitalizes on a once-in-a-life-time opportunity afforded by the
quantifiable manipulation of air quality in Beijing, China during the 2008 Olympics and Paralympics. A series of
aggressive pollution-control measures, implemented from July 20 to September 19, 2008, resulted in drastic
reductions in air pollutant concentrations during this well-defined period. The marked temporary improvement
in air quality within this 2-month time window provides a unique natural experiment, enabling us to explore
population-wide effects of PNAPE on ASD during specific stages of prenatal (and early post-natal)
development in a large urban population of children. This project will first characterize quantitative ASD traits
and estimate ASD prevalence. Subsequently, the association of PNAPE with ASD will be evaluated, assessing
ASD as both a categorical diagnosis and as a continuous trait. The proposed study will advance our scientific
understanding of ASD trait distribution in a well-defined population, elucidate the effect of PNAPE on ASD risk,
examine whether specific PNAPE windows differentially alter ASD risk, and determine whether birth outcomes
mediate the associations. The specific aims are: 1) Estimate population-based prevalence of ASD in Beijing
City among children who were in utero before, during, and after the Olympic period; 2) Assess time-window-
specific PNAPE effects on ASD; and 3) Investigate the extent to which the effect of PNAPE on ASD and ASD
traits is mediated by birthweight and gestational age at birth. We will also show the feasibility of establishing a
biosample repository in this population by collecting saliva samples and accessing banked cord blood. This will
enable future investigations of genetic or epigenetic mechanisms involved in PNAPE associations with ASD
and related quantitative traits. The investigative team is uniquely poised to exploit the rare population-wide
natural experiment of a massive air quality intervention. We have experience and expertise in ASD screening
and assessment in Chinese populations, with surveillance and trait psychometrics, and in air pollution
assessment. This study explores the potential for reducing early-life air pollution exposure as a public-health
intervention to lessen ASD risk.

## Key facts

- **NIH application ID:** 9967082
- **Project number:** 5R01ES030414-02
- **Recipient organization:** JOHNS HOPKINS UNIVERSITY
- **Principal Investigator:** Christine Ladd-Acosta
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $600,420
- **Award type:** 5
- **Project period:** 2019-07-01 → 2025-03-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9967082

## Citation

> US National Institutes of Health, RePORTER application 9967082, Trimester-Specific Variation in Air Quality and Risk for Autism Spectrum Disorder: A Natural Experiment (5R01ES030414-02). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/9967082. Licensed CC0.

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