Greener residential environment is associated with increased bacterial diversity in outdoor ambient air

Jennifer N Styles; Andrey I Egorov; Shannon M Griffin; Jo Klein; J W Scott; Elizabeth A Sams; Edward Hudgens; Chris Mugford; Jill R Stewart; Kun Lu; Ilona Jaspers; Scott P Keely; Nichole E Brinkman; Jason W Arnold; Timothy J Wade

doi:10.1016/j.scitotenv.2023.163266

Greener residential environment is associated with increased bacterial diversity in outdoor ambient air

Sci Total Environ. 2023 Jul 1:880:163266. doi: 10.1016/j.scitotenv.2023.163266. Epub 2023 Apr 5.

Authors

Affiliations

¹ United States Environmental Protection Agency, Center for Public Health and Environmental Assessment, Office of Research and Development, Research Triangle Park, NC, USA; Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC, USA; Department of Pediatrics, Division of Allergy and Immunology, Chapel Hill, NC, USA. Electronic address: [email protected].
² United States Environmental Protection Agency, Center for Public Health and Environmental Assessment, Office of Research and Development, Research Triangle Park, NC, USA.
³ United States Environmental Protection Agency, Center for Public Health and Environmental Assessment, Office of Research and Development, Cincinnati, OH, USA.
⁴ United States Environmental Protection Agency, Center for Public Health and Environmental Assessment, Office of Research and Development, Research Triangle Park, NC, USA; North Carolina State University Libraries, Raleigh, NC, USA.
⁵ United States Public Health Service Commissioned Corps, Research Triangle Park, NC, USA; The Agency for Toxic Substances and Disease Registry, Boston, MA, USA.
⁶ Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC, USA.
⁷ Curriculum in Toxicology and Environmental Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA; Center for Environmental Medicine, Asthma, and Lung Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA; Department of Pediatrics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
⁸ United States Environmental Protection Agency, Center for Environmental Measurement and Monitoring, Office of Research and Development, Cincinnati, OH, USA.
⁹ United States Environmental Protection Agency, Center for Environmental Solutions and Emergency Response, Office of Research and Development, Cincinnati, OH, USA.
¹⁰ Division of Gastroenterology and Hepatology, Department of Medicine, Microbiome Core Facility, Center for Gastrointestinal Biology and Disease, School of Medicine, University of North Carolina, Chapel Hill, NC, USA; Department of Molecular Genetics and Microbiology, Duke Microbiome Center, Duke University, Durham, NC, USA.

PMID: 37028654
DOI: 10.1016/j.scitotenv.2023.163266

Abstract

In urban areas, exposure to greenspace has been found to be beneficial to human health. The biodiversity hypothesis proposed that exposure to diverse ambient microbes in greener areas may be one pathway leading to health benefits such as improved immune system functioning, reduced systemic inflammation, and ultimately reduced morbidity and mortality. Previous studies observed differences in ambient outdoor bacterial diversity between areas of high and low vegetated land cover but didn't focus on residential environments which are important to human health. This research examined the relationship between vegetated land and tree cover near residence and outdoor ambient air bacterial diversity and composition. We used a filter and pump system to collect ambient bacteria samples outside residences in the Raleigh-Durham-Chapel Hill metropolitan area and identified bacteria by 16S rRNA amplicon sequencing. Geospatial quantification of total vegetated land or tree cover was conducted within 500 m of each residence. Shannon's diversity index and weighted UniFrac distances were calculated to measure α (within-sample) and β (between-sample) diversity, respectively. Linear regression for α-diversity and permutational analysis of variance (PERMANOVA) for β-diversity were used to model relationships between vegetated land and tree cover and bacterial diversity. Data analysis included 73 ambient air samples collected near 69 residences. Analysis of β-diversity demonstrated differences in ambient air microbiome composition between areas of high and low vegetated land (p = 0.03) and tree cover (p = 0.07). These relationships remained consistent among quintiles of vegetated land (p = 0.03) and tree cover (p = 0.008) and continuous measures of vegetated land (p = 0.03) and tree cover (p = 0.03). Increased vegetated land and tree cover were also associated with increased ambient microbiome α-diversity (p = 0.06 and p = 0.03, respectively). To our knowledge, this is the first study to demonstrate associations between vegetated land and tree cover and the ambient air microbiome's diversity and composition in the residential ecosystem.

Keywords: 16S rRNA; Aerobiome; Airborne Bacteria; Greenspace; Microbiome; Outdoor air.

MeSH terms

Bacteria
Biodiversity*
Ecosystem*
Humans
Linear Models
RNA, Ribosomal, 16S / genetics
Trees / genetics

Substances

RNA, Ribosomal, 16S