County-level exposures to greenness and associations with COVID-19 incidence and mortality in the United States

Abstract

Background COVID-19 is an infectious disease that has killed more than 555,000 people in the US. During a time of social distancing measures and increasing social isolation, green spaces may be a crucial factor to maintain a physically and socially active lifestyle while not increasing risk of infection. Objectives We evaluated whether greenness was related to COVID-19 incidence and mortality in the US. Methods We downloaded data on COVID-19 cases and deaths for each US county up through June 7, 2020, from Johns Hopkins University, Center for Systems Science and Engineering Coronavirus Resource Center. We used April-May 2020 Normalized Difference Vegetation Index (NDVI) data, to represent the greenness exposure during the initial COVID-19 outbreak in the US. We fitted negative binomial mixed models to evaluate associations of NDVI with COVID-19 incidence and mortality, adjusting for potential confounders such as county-level demographics, epidemic stage, and other environmental factors. We evaluated whether the associations were modified by population density, proportion of Black residents, median home value, and issuance of stay-at-home orders. Results An increase of 0.1 in NDVI was associated with a 6% (95% Confidence Interval: 3%, 10%) decrease in COVID-19 incidence rate after adjustment for potential confounders. Associations with COVID-19 incidence were stronger in counties with high population density and in counties with stay-at-home orders. Greenness was not associated with COVID-19 mortality in all counties; however, it was protective in counties with higher population density. Discussion Exposures to NDVI were associated with reduced county-level incidence of COVID-19 in the US as well as reduced county-level COVID-19 mortality rates in densely populated counties.

Review of Associations between Built Environment Characteristics and Severe Acute Respiratory Syndrome Coronavirus 2 Infection Risk

“…Population density Linear mixed effect models After accounting for known mechanisms behind transmission rates, we found that park use decreased residual pre-peak case rates, especially when greenspace was low and contiguous. 11 Klompmaker, Hart [ 40 ] US Cross-sectional County 3089 Incidence NDVI Negative binomial mixed models 1. An increase of 0.1 in NDVI was associated with a 6% decrease in COVID-19 incidence rate.…”

Greenspace and park use associated with less emotional distress among college students in the United States during the COVID-19 pandemic

“…Research has also shown that youth ( Jackson et al, 2021 ) and adults ( Cindrich et al, 2021 ; Poortinga et al, 2021 ; Pouso et al, 2021 ; Ribeiro et al, 2021 ) who maintained outdoor activity during the pandemic reported better psychological health outcomes than those who did not go outside. Greenspace exposure, often measured based on proximity and access, has also been associated with lower COVID-19 mortality, infection, and racial disparities in infection rates in the United States ( Klompmaker et al, 2021 ; Lu et al, 2021a , 2021b ; Pan et al, 2021 ; Russette et al, 2021 ; You and Pan, 2020 ); in other parts of the world, however, associations between COVID-19 mortality and infection rates and greenspace are mixed ( Labib et al, 2021 ; Ribeiro et al, 2021 ; Viezzer and Biondi, 2021 ; You et al, 2020 ). Collectively, these studies highlight the wide range of health benefits that outdoor recreation and park use might provide in the era of COVID-19 ( Soga et al, 2021a ), yet underscore the need for additional research.…”

Nature’s contributions in coping with a pandemic in the 21st century: A narrative review of evidence during COVID-19

“…Nguyen et al (2020) studied 30,556 zip code level COVID-19 cases during June 2020 and observed that zip codes with higher levels of greenery along streets (>30%) had fewer COVID cases than zip codes with lower levels of greenery along streets. Klompmaker et al (2021) found that higher neighborhood greenness was significantly associated with lower COVID incidence rates among 3,089 U.S. counties (6% reduction per 0.1 increase in NDVI), but greenness was not related to COVID mortality at population level but correlated for subgroup level mortality. Several other studies investigated COVID outcomes with residential greenness in counties across the USA and found higher residential greenness associated with reduced COVID-19 mortality (Lee et al, 2021;Lu et al, 2021a;Russette et al, 2021).…”

“…In the U.S., white respondents reported lower levels of psychological wellbeing when they felt that the COVID-19 pandemic had restricted their access to nature; in contrast, nonwhite respondents reported higher levels of psychological well-being when they felt restrictions in nature access during the pandemic (Tomasso et al, 2021). U.S. counties with greater shares of Black residents showed no differences in associations between green space and COVID incidence than counties with lower shares of Black residents; further, counties with the smallest shares of Black residents showed positive associations between green space and COVID-related mortality (Klompmaker et al, 2021). This finding suggests harmful associations between green space and COVID mortality in areas with low levels of Black residents.…”

“…In measuring nature exposure during COVID-19, several studies considered residential neighborhood-based measures of green space availability. The majority of these studies used satellite image derived vegetation indices (e.g., normalized difference vegetation index [NDVI]), land use and land cover datasets (e.g., percentage green space, green space density), or self-reported perceived level of neighborhood greenery (Dzhambov et al, 2020;Lu et al, 2021a;You and Pan, 2020;Klompmaker et al, 2021). Concurrently, studies also investigated window view-based greenness exposure to understand the type of nature exposure people may observe from the indoors during lockdowns.…”