New Insights for Tracking Global and Local Trends in Exposure to Air Pollutants.

Over six million people die prematurely each year from exposure to air pollution. Current air quality metrics insufficiently monitor exposure to air pollutants. This gap hinders the ability of decisionmakers to address the public health impacts of air pollution. To spur new emissions control policies and ensure implemented solutions realize meaningful gains in environmental health, we develop a framework of public-health-focused air quality indicators that quantifies over 200 countries' trends in exposure to particulate matter, ozone, nitrogen oxides, sulfur dioxide, carbon monoxide, and volatile organic compounds. We couple population density to ground-level pollutant concentrations to derive population-weighted exposure metrics that quantify the pollutant levels experienced by the average resident in each country. Our analyses demonstrate that most residents in 171 countries experience pollutant levels exceeding international health guidelines. In addition, we find a negative correlation between temporal trends in ozone and nitrogen oxide concentrations, which─when qualitatively interpreted with a simple atmospheric chemistry box model─can help describe the apparent tradeoff between the mitigation of these two pollutants on local scales. These novel indicators and their applications enable regulators to identify their most critical pollutant exposure trends and allow countries to track the performance of their emission control policies over time.

Business Leadership in Global Climate Change Responses.

In the 2015 Paris Climate Change Agreement, 195 countries committed to reducing greenhouse gas emissions in recognition of the scientific consensus on the consequences of climate change, including substantial public health burdens. In June 2017, however, US president Donald Trump announced that the United States would not implement the Paris Agreement. We highlight the business community's backing for climate change action in the United States. Just as the US federal government is backing away from its Paris commitments, many corporate executives are recognizing the need to address the greenhouse gas emissions of their companies and the business logic of strong environmental, social, and governance practices more generally. We conclude that climate change could emerge as an issue on which the business and public health communities might align and provide leadership.

Temporal variation in association between short-term exposure to fine particulate matter and hospitalisations in older adults in the USA: a long-term time-series analysis of the US Medicare dataset.

BACKGROUND: Short-term exposure to fine particulate matter (PM2·5) is associated with increased risk of hospital admissions and mortality, and health risks differ by the chemical composition of PM2·5. Policies to control PM2·5 could change its chemical composition and total mass concentration, leading to change in the subsequent health impact. However, there is little ence on whether associations between PM2·5 and health exhibit temporal variation. We investigated whether risks of hospitalisations from short-term exposure to PM2·5 varied over time in the USA. METHODS: We did a time-series analysis using a national dataset comprising daily circulatory and respiratory hospitalisation rates of Medicare beneficiaries (age ≥65 years) and PM2·5 in 173 US counties from 1999 to 2016. We fitted modified quasi-Poisson models to estimate temporal trends of associations within a county, and pooled county-level estimates using Bayesian hierarchical modelling to generate an overall estimate. FINDINGS: The study included 10 559 654 circulatory and 3 027 281 respiratory hospitalisations. We identified changes in the national average association between previous-day PM2·5 and respiratory hospitalisation over time, with a U-shape that is robust under stratification, linear, and non-linear models. The change in risk of respiratory hospitalisation per 10 µg/m3 increase in previous-day PM2·5 decreased from 0·75% (95% posterior credible interval 0·05 to 1·46) in 1999 to -0·28% (-0·79 to 0·23) in 2008, and then increased to 1·44% (0·00 to 2·91) in 2016. No statistically significant temporal change was observed for associations between same-day PM2·5 and circulatory hospitalisation. INTERPRETATION: Hospitalisation risk from PM2·5 changes over time and has increased over the past 7 years in study, especially in northeastern USA. The temporal trend differs by cause of hospitalisation. This study emphasises the necessity of evaluating temporal heterogeneity in health impacts of PM2·5 and suggests caution in applying association estimates to a different time period. FUNDING: US Environmental Protection Agency and Yale Institute for Biospheric Studies.

Where is global waste management heading? An analysis of solid waste sector commitments from nationally-determined contributions.

Waste-sector greenhouse gas emissions have long been accepted as a critical component of climate change mitigation efforts because of the significant radiative forcing of methane (CH4) production from municipal landfills and other emissions from waste management processes. In developed countries, waste generation is expected to peak and decline by the end of the century, whereas waste generation is rapidly rising in many developing nations. The extent to which the countries of the world are planning to handle future quantities of waste has not been explored in detail. This work provides the first detailed account of future waste management planning and waste-sector mitigation strategies through an analysis of stated commitments in the 174 Nationally Determined Contributions (NDCs, documents outlining each country's actions to mitigate carbon emissions and adapt to a changing climate) that have been filed to date within the Framework Convention on Climate Change secretariat in Bonn. One-hundred thirty-seven of 174 countries that submitted NDCs included waste-sector emission mitigation actions, representing approximately 85% of all global emissions. About half (67) of the countries that included waste sector mitigation tactics identified infrastructure or policy actions to meet mitigation commitments, but these strategies vary widely in their scope and level of detail. Landfilling was the most commonly-cited waste-sector commitment (n = 47), followed by deriving energy from waste through various techniques (n = 42). Countries targeting improved solid waste collections had less extensive coverage (µcollection = 38% of generated waste collected) than countries that did not prioritize improved collections (µcollection = 46% of waste generation), but countries not prioritizing the waste sector at all in NDCs had the most limited waste collection coverage (µcollection = 33%). Almost all of the countries that specified emissions inventory assumptions (132 of 135) use outdated CH4 global warming potential values which, coupled with missing or poor waste management data suggests many countries may be underestimating the importance of waste sector emissions in national emissions portfolios. Several examples of data collection and reporting models are identified that can help to inform and potentially improve life-cycle environmental outcomes in the waste sector. Adaptation strategies detailed in NDCs have largely overlooked the waste sector, suggesting inadequate incorporation of future climate scenarios in waste sector infrastructure planning.