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Int J Hyg Environ Health. 2020 Jan;223(1):187-198. doi: 10.1016/j.ijheh.2019.09.003. Epub 2019 Sep 19.

Estimated time-varying exposures to air emissions from animal feeding operations and childhood asthma.

Author information

1
Department of Environmental and Occupational Health Sciences, School of Public Health, Box 357234, University of Washington, Seattle, WA, 98195, United States. Electronic address: cloftus@uw.edu.
2
Department of Environmental and Occupational Health Sciences, School of Public Health, Box 357234, University of Washington, Seattle, WA, 98195, United States.
3
Department of Statistics, College of Arts and Sciences, Box 354322, University of Washington, Seattle, WA, 98195, United States.
4
Northwest Communities Education Center, Radio KDNA, 121 Sunnyside Ave, Granger, WA, 98932, United States.
5
Yakima Valley Farm Workers Clinic, Yakima, WA, United States.
6
Department of Environmental and Occupational Health Sciences, School of Public Health, Box 357234, University of Washington, Seattle, WA, 98195, United States; Department of Pediatrics, School of Medicine, Box 356320, University of Washington, Seattle, WA, 98195, United States.

Abstract

BACKGROUND/AIM:

Industrial-scale animal feeding operations (AFOs) have adverse impacts on regional air quality. Air emissions include endotoxins and other pro-inflammatory components, and exposure may cause airway inflammation and respiratory effects in susceptible individuals residing nearby. We aimed to develop and validate metrics for estimating time-varying exposure to AFO air pollution in surrounding communities and, secondly, to determine whether exposure is associated with health effects in children with asthma.

METHODS:

We conducted a longitudinal panel study of N = 58 children with asthma in an agricultural region of Washington State with a high density of dairy AFOs. Children were followed for up to 26 months with repeated measures of respiratory health (N = 2023 interviews; N = 3853 lung function measurements); urine was collected in a subcohort (N = 16) at six-day intervals over three months and analyzed for leukotriene E4 (LTE4), a biomarker of systemic inflammation (N = 138 measurements). We developed an approach to estimate daily exposure to AFO airborne emissions based on distance to AFOs, AFO size, and daily wind speed and direction, and validated the estimates against direct measurements of ammonia, a chemical marker of AFO emissions, measured biweekly at 18 sites across the region for 14 months. Short-term relationships between AFO pollutant exposure and outcomes were assessed using regression models accounting for within-participant correlation and several potential confounders.

RESULTS:

Estimates of daily AFO air pollution correlated moderately well with outdoor ammonia measurements (N = 842; r = 0.62). Forced expiratory volume in 1 s (FEV1) as percent of predicted was 2.0% (95% CI: 0.5, 3.5) lower with each interquartile increase in previous day exposure, but no associations with asthma symptoms were observed. There was suggestive evidence that LTE4 concentrations were higher following days of elevated exposure to AFO emissions (p = 0.06).

CONCLUSIONS:

A simple metric of time-varying exposure to AFO emissions was correlated with daily outdoor ammonia levels. Children with asthma may be adversely affected by exposure to AFO emissions.

KEYWORDS:

Agriculture; Air pollution; Animal feeding operations; Dairy farms; Industrial food production; Pediatric asthma

PMID:
31543304
PMCID:
PMC7020853
[Available on 2021-01-01]
DOI:
10.1016/j.ijheh.2019.09.003

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