Dataset Information

A National Multicity Analysis of the Causal Effect of Local Pollution, [Formula: see text], and [Formula: see text] on Mortality.

ABSTRACT:

Background

Studies have long associated [Formula: see text] with daily mortality, but few applied causal-modeling methods, or at low exposures. Short-term exposure to [Formula: see text], a marker of local traffic, has also been associated with mortality but is less studied. We previously found a causal effect between local air pollution and mortality in Boston.

Objectives

We aimed to estimate the causal effects of local pollution, [Formula: see text], and [Formula: see text] on mortality in 135 U.S. cities.

Methods

We used three methods which, under different assumptions, provide causal marginal estimates of effect: a marginal structural model, an instrumental variable analysis, and a negative exposure control. The instrumental approach used planetary boundary layer, wind speed, and air pressure as instruments for concentrations of local pollutants; the marginal structural model separated the effects of [Formula: see text] from the effects of [Formula: see text], and the negative exposure control provided protection against unmeasured confounders.

Results

In 7.3 million deaths, the instrumental approach estimated that mortality increased 1.5% [95% confidence interval (CI): 1.1%, 2.0%] per [Formula: see text] increase in local pollution indexed as [Formula: see text]. The negative control exposure was not associated with mortality. Restricting our analysis to days with [Formula: see text] below [Formula: see text], we found a 1.70% (95% CI 1.11%, 2.29%) increase. With marginal structural models, we found positive significant increases in deaths with both [Formula: see text] and [Formula: see text]. On days with [Formula: see text] below [Formula: see text], we found a 0.83% (95% CI 0.39%, 1.27%) increase. Including negative exposure controls changed estimates minimally.

Conclusions

Causal-modeling techniques, each subject to different assumptions, demonstrated causal effects of locally generated pollutants on daily deaths with effects at concentrations below the current EPA daily [Formula: see text] standard. https://doi.org/10.1289/EHP2732.

SUBMITTER: Schwartz J

PROVIDER: S-EPMC6375387 | biostudies-literature | 2018 Aug

REPOSITORIES: biostudies-literature

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Publications

A National Multicity Analysis of the Causal Effect of Local Pollution, NO 2 , and PM 2.5 on Mortality.

Schwartz Joel J Fong Kelvin K Zanobetti Antonella A

Environmental health perspectives 20180801 8

<h4>Background</h4>Studies have long associated PM2.5 with daily mortality, but few applied causal-modeling methods, or at low exposures. Short-term exposure to NO2, a marker of local traffic, has also been associated with mortality but is less studied. We previously found a causal effect between local air pollution and mortality in Boston.<h4>Objectives</h4>We aimed to estimate the causal effects of local pollution, PM2.5, and NO2 on mortality in 135 U.S. cities.<h4>Methods</h4>We used three me ...[more]

PMID: 30235421

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