Long-term ozone exposure and associated cause-specific mortality risks with adjusted metrics by cohort studies: A systematic review and meta-analysis

ABSTRACTBACKGROUNDLong-term ozone (O3) exposure could lead to a series of non-communicable diseases and increase the mortality risks. However, cohort-based studies were still rather rare, and inconsistent exposure metrics might impair the credibility of epidemiological evidence synthetisation. To provide more accurate meta-estimation, this review updated the systematic review with inclusion of recent studies and summarised the quantitative associations between O3 exposure and cause-specific mortality risks based on unified exposure metrics.METHODSResearch articles reporting relative risks between incremental long-term O3 exposure and causes of mortality covering all-cause, cardiovascular diseases, respiratory diseases, chronic obstructive pulmonary disease, pneumonia, ischaemic heart diseases, ischaemic stroke, congestive heart failure, cerebrovascular diseases, and lung cancer, estimated from cohort studies were identified through systematic searches in MEDLINE, Embase and Web of Science. Cross-metric conversion factors were estimated linearly by decadal of observations during 1990-2019. DerSimonian and Laird random effect meta-regression was applied to pool the relative risks.RESULTSA total of 20 studies involving 97,766,404 participants were included in the systematic review. After linearly adjusting the inconsistent O3 exposure metrics into congruity, the pooled relative risks (RR) associated with every 10 nmol mol-1 (ppbV) incremental O3 exposure, by mean of warm-season daily maximum 8-hour average metric, was: 1.010 with 95% confidence interval (CI) ranging 1.005–1.015 for all-cause mortality; 1.027 (95% CI: 1.004–1.049) for respiratory mortality; 1.061 (95% CI: 1.006– 1.119) for COPD mortality; 1.028 (95% CI: 1.001–1.058) for cardiovascular mortality; and 1.102 (95% CI: 1.046–1.162) for congestive heart failure mortality. Positive but insignificant mortality risk associations were found for ischaemic heart diseases, stroke, pneumonia, and lung cancer.DISCUSSIONSThis review covered up-to-date studies, expanded the O3-exposure associated mortality causes into wider range of categories, and firstly highlighted the issue of inconsistency in O3 exposure metrics. Non-intercept linear regression-based cross-metric RR conversion was another innovation, but limitation lay in the observation reliance, indicating further calibration with more credible observations available. Large uncertainties in the multi-study pooled RRs would inspire more future studies to corroborate or contradict the results from this review.CONCLUSIONSAdjustment for exposure metrics laid more solid foundation for multi-study meta-analysis, the results of which revealed unneglectable cardiopulmonary hazards from long-term O3 exposure.REGISTRATIONThe review was registered in PROSPERO (CRD42021270637).FUNDINGThis study is mainly funded by UK Natural Environment Research Council, UK National Centre for Atmospheric Science, Australian Research Council and Australian National Health and Medical Research Council.HighlightsUpdated evidence for O3-mortality associations from 20 cohorts has been provided.Adjusted various O3exposure metrics can provide more accurate risk estimations.Long-term O3-exposure was associated with increased mortality from all-causes, respiratory disease, COPD, cardiovascular disease and congestive heart failure.

High survival following bleaching highlights the resilience of a highly disturbed region of the Great Barrier Reef

Natural bleaching events provide an opportunity to examine how local scale environmental variation influences bleaching severity and recovery. During the 2020 marine heatwave, we documented widespread and severe coral bleaching (75 – 98% of coral cover) throughout the Keppel Islands in the Southern inshore Great Barrier Reef. Acropora, Pocillopora and Porites were the most severely affected genera, while Montipora was comparatively less susceptible. Site-specific heat-exposure metrics were not correlated with Acropora bleaching severity, but recovery was faster at sites that experienced lower heat exposure. Despite severe bleaching and exposure to accumulated heat that often results in coral mortality (degree heating weeks ~ 4 – 8), cover remained stable. Approximately 94% of fate-tracked Acropora millepora colonies survived, perhaps owing to reduced irradiance stress from high turbidity, heterotrophic feeding, and large tidal flows that can increase mass transfer. Severe bleaching followed by rapid recovery, and the continuing dominance of Acropora populations in the Keppel Islands is indicative of high resilience. These coral communities have survived an 0.8 °C increase in average temperatures over the last 150 years. However, recovery following the 2020 bleaching was driven by the easing of thermal stress, which may challenge their recovery potential under further warming.

The effects of hydraulic fracturing activities on birth outcomes are evident in a non-individualized county-wide aggregate data sample from Colorado

Background: There is growing concern about the recent increase in oil and gas development using hydraulic fracturing. Studies linking adverse birth outcomes and maternal proximity to hydraulic fracturing wells exist but tend to use individualized maternal and infant data contained in protected health care records. In this study, we extended the findings of these past studies to evaluate if analogous effects detected with individualized data could be detected from non-individualized county-wide aggregated data.Design and Methods: This study used a retrospective cohort of 252,502 birth records from 1999 to 2019 gathered from a subset sample of 5 counties in the state of Colorado where hydraulic fracturing activities were conducted. We used Generalized Linear Models to evaluate the effect of county-wide well density and production data over unidentified birth weight, and prematurity data. Covariates used in the model were county-wide statistics sourced from the US Census.Results: Our modeling approach showed an interesting effect where hydraulic fracturing exposure metrics have a mixed effect directional response. This effect was detected on birth weight when well density, production and their interaction are accounted for. The interaction effect provides an additional interpretation to discrepancies reported previously in the literature. Our approach only detected a positive association to prematurity with increased production.Conclusions: Our findings demonstrate two main points: First, the effect of hydraulic fracturing is detectable by using county-wide unidentified data. Second, the effect of hydraulic fracturing can be complicated by the number of operations and the intensity of the activities in the area.

Urban Nature and Public Health: How Nature Exposure and Sociocultural Background Relate to Depression Risk

As the world’s population becomes more urbanized, there is an associated decrease in nature exposure and a rise in noncommunicable diseases, including depression. Previous cross-sectional studies examining urban nature exposure and depression have reported favorable associations. However, many of these studies rely primarily on nature exposure metrics that measure the intensity of nature exposure, while other dimensions of urban nature exposure remain understudied. Therefore, in a cross-sectional, questionnaire-based case study targeting a general urban population (n = 282), we examined the relationship between two less commonly studied urban nature exposure variables (i.e., gardening behavior and greenspace visit frequency) and depression risk while also considering sociocultural background (multivariate logistic regression model). Results indicated that being a gardener was significantly associated with a reduced odds of being at risk of depression and that having a family migration history, but not a self-migration history, was associated with increased odds of being at risk of depression. In the examination of neighborhood socialization frequency and depression risk, we did not determine any significant association. The results of this study, therefore, highlight the importance of considering both people’s sociocultural backgrounds and urban nature exposure in more detail to help plan for and support healthier cities in the future.

Quantified Exposures from Potential Deepwater Releases for Comparative Risk Assessment of Oil Spill Response Options Including Dispersant Use

ABSTRACT The goal of oil spill response is to mitigate the overall impacts of spilled oil on ecological and socioeconomic resources. Surface and subsea dispersant applications are effective tools that remain controversial after decades of research and discussion. The tradeoff that dispersants potentially increase effects on water column and benthic communities while reducing floating and nearshore/shoreline oil exposure is recognized, but inevitably are qualitatively considered when subjectivity and stakeholder interests prevail. To be objective and transparent, we developed a quantitative approach using oil spill modeling to evaluate response alternatives in a Comparative Risk Assessment (CRA) framework where the fractions of resources potentially exposed are compared, along with their recovery potential. The model quantifies exposure as water surface area, shoreline area and water volume exposed above thresholds of concern, multiplied by duration of exposure, in each environmental compartment. These exposure metrics (i.e., area-days or volume-days) are multiplied by relative densities across the environmental compartments to evaluate the fractions of the resources exposed in each modeled scenario. The fractions of resources exposed, along with their recovery potential, inform decisionmakers using a Spill Impact Mitigation Assessment (SIMA) approach with quantitative estimates of potential consequences, which they may consider along with stakeholder values. Previously, we evaluated a deepwater blowout in the Gulf of Mexico, assuming no intervention or various response options (mechanical recovery, in-situ burning, surface dispersant application, and subsea dispersant injection [SSDI]). The findings were that inclusion of SSDI reduced human and wildlife exposure to volatile organic compounds; dispersed oil into a large water volume at depth; enhanced biodegradation; and reduced surface water, nearshore and shoreline exposure to floating oil and entrained/dissolved oil in the upper water column. Tradeoffs included increased exposures at depth. However, since organisms are less abundant at depth, overall exposure of valued ecosystem components was minimized by use of SSDI. Follow-up modeling shows the benefits of SSDI are due to reduction of the oil droplet sizes released to the water column. Droplet sizes are sensitive to oil and gas release rates, release depth, orifice size and dispersant-to-oil ratio. The exposure metrics resulting from a matrix of scenarios varying these inputs and response actions are expected to be generally representative of the fate and behavior of oil and gas blowouts in the offshore areas of the Gulf of Mexico, as well as other regions with similar oceanographic conditions.

Impacts of Surface Ozone Pollution on Global Crop Yields: Comparing Different Ozone Exposure Metrics and Incorporating Co-effects of CO2

Surface ozone (O3) pollution poses significant threats to crop production and food security worldwide, but an assessment of present-day and future crop yield losses due to exposure to O3 still abides with great uncertainties, mostly due: (1) to the large spatiotemporal variability and uncertain future projections of O3 concentration itself; (2) different methodological approaches to quantify O3 exposure and impacts; (3) difficulty in accounting for co-varying factors such as CO2 concentration and climatic conditions. In this paper, we explore these issues using a common framework: a consistent set of simulated present-day O3 fields from one chemical transport model, coupled with a terrestrial ecosystem-crop model to derive various O3 exposure metrics and impacts on relative crop yields worldwide, and examine the potential effects of elevated CO2 on O3-induced crop yield losses. Throughout, we review and explain the differences in formulation and parameterization in the various approaches, including the concentration-based metrics, flux-based metrics, and mechanistic biophysical crop modeling. We find that while the spatial pattern of yield losses for a given crop is generally consistent across metrics, the magnitudes can differ substantially. Pooling the concentration-based and flux-based metrics together, we estimate the present-day globally aggregated yield losses to be: 3.6 ± 1.1% for maize, 2.6 ± 0.8% for rice, 6.7 ± 4.1% for soybean, and 7.2 ± 7.3% for wheat; these estimates are generally consistent with previous studies but on the lower end of the uncertainty range covered. We attribute the large combined uncertainty mostly to the differences among methodological approaches, and secondarily to differences in O3 and meteorological inputs. Based on a biophysical crop model that mechanistically simulates photosynthetic and yield responses of crops to stomatal O3 uptake, we further estimate that increasing CO2 concentration from 390 to 600 ppm reduces the globally aggregated O3-induced yield loss by 21–52% for maize and by 27–38% for soybean, reflecting a CO2-induced reduction in stomatal conductance that in turn alleviates stomatal O3 uptake and thus crop damage. Rising CO2 may therefore render the currently used exposure-yield relationships less applicable in a future atmosphere, and we suggest approaches to address such issues.

What dataset should I choose? The influence of data choices on flood exposure estimations at national scales

<p>There are currently several large-scale gridded archives available for the study of flood exposure, and the results will inevitably depend on the datasets included in the analysis. The purpose of this work is to demonstrate how country flood exposure, here represented as the presence of population within floodplains, is influenced by dataset choices.</p><p>We conduct this geographical analysis in two parts. First, we conduct a global analysis showing how different flood exposure metrics influence comparisons between countries. Second, we overlay five commonly used gridded archives (three population archives and two floodplain archives) for 32 countries. The purpose is to quantify the influence of data choices, while also giving an overview of the various dataset methodologies. We finally zoom in on areas where the five datasets yield very dissimilar results, to exemplify typical differences among the datasets.</p>