# Spatial Causal Inference for Wildland Fire Smoke Effects on Air Pollution and Health

> **NIH NIH R01** · NORTH CAROLINA STATE UNIVERSITY RALEIGH · 2021 · $289,186

## Abstract

PROJECT SUMMARY
Wildland ﬁre smoke is a major contributor to air pollution in the United States (US) and is associated with a wide
range of health risks. The number and intensity of wildland ﬁres are expected to increase with a changing climate;
therefore, there is a pressing need to accurately quantify the extent to which wildland ﬁre smoke contributes to air
pollution levels and corresponding health burden, and to evaluate the effectiveness of preventative measures to
mitigate the health burden. However, this work presents many challenges. Exposure to wildland ﬁres clearly can-
not be randomized, so we rely on spatially-correlated observational data and causal inference. While there is an
impressive literature on causal inference for independent data, the methods available for spatial data are limited.
Progress in the spatial setting has been slow due to complexities induced by spatial correlations and interference,
i.e., the effect of treatment at one location depends on the response at nearby locations. We also analyze data
from Smoke Sense, an Environmental Protection Agency (EPA)-sponsored citizen science project designed to
engage citizens that experience the effects of ﬁre smoke using smart-phone applications (app). Citizen science
studies have transformative potential to amass valuable data and engage the public in scientiﬁc research, but can
be plagued by self selection of treatment and complex missing data patterns. The overarching theme of the
proposal is to develop a suite of casual analysis tools to analyze observational spatial data and data aris-
ing from smart-phone applications, handling interference, spatially-varying treatment effects, informative
missingness and spatial unmeasured confounders. In Aim 1, we provide a new formulation of spatial interfer-
ence using kernel distance functions. We extend marginal structural models and structural nested mean models
to the setting with spatial interference and propose doubly-robust estimators of direct and indirect/spillover effects.
We will apply this new method to estimate wildland ﬁre smoke effects on air pollution levels and health burden.
Because of subject heterogeneity in response to treatment, it is desirable to develop personalized recommenda-
tion strategies to determine which treatment works best, for whom, and under what circumstances. In Aim 2 we
propose a novel causal model that describes how treatment effects vary over space and with evolving subject
characteristics. Using the Smoke Sense data, we will estimate heterogeneous effects of app engagement and
preventative measures to mitigate the impact of wildland ﬁre smoke. We also propose an instrumental variable
approach to handling informative missingness, which arises frequently in studies with smart phone applications
and can lead to invalid inference if not properly addressed. In Aim 3 we build on our previous work to adjust for
missing spatial confounders by modeling the relationship between the treatment and the ...

## Key facts

- **NIH application ID:** 10134344
- **Project number:** 5R01ES031651-02
- **Recipient organization:** NORTH CAROLINA STATE UNIVERSITY RALEIGH
- **Principal Investigator:** Brian J. Reich
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $289,186
- **Award type:** 5
- **Project period:** 2020-04-01 → 2024-01-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10134344

## Citation

> US National Institutes of Health, RePORTER application 10134344, Spatial Causal Inference for Wildland Fire Smoke Effects on Air Pollution and Health (5R01ES031651-02). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10134344. Licensed CC0.

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