Long-term mortality burden trends attributed to black carbon and PM2·5 from wildfire emissions across the continental USA from 2000 to 2020: a deep learning modelling study.

BACKGROUND: Long-term improvements in air quality and public health in the continental USA were disrupted over the past decade by increased fire emissions that potentially offset the decrease in anthropogenic emissions. This study aims to estimate trends in black carbon and PM2·5 concentrations and their attributable mortality burden across the USA. METHODS: In this study, we derived daily concentrations of PM2·5 and its highly toxic black carbon component at a 1-km resolution in the USA from 2000 to 2020 via deep learning that integrated big data from satellites, models, and surface observations. We estimated the annual PM2·5-attributable and black carbon-attributable mortality burden at each 1-km2 grid using concentration-response functions collected from a national cohort study and a meta-analysis study, respectively. We investigated the spatiotemporal linear-regressed trends in PM2·5 and black carbon pollution and their associated premature deaths from 2000 to 2020, and the impact of wildfires on air quality and public health. FINDINGS: Our results showed that PM2·5 and black carbon estimates are reliable, with sample-based cross-validated coefficients of determination of 0·82 and 0·80, respectively, for daily estimates (0·97 and 0·95 for monthly estimates). Both PM2·5 and black carbon in the USA showed significantly decreasing trends overall during 2000 to 2020 (22% decrease for PM2·5 and 11% decrease for black carbon), leading to a reduction of around 4200 premature deaths per year (95% CI 2960-5050). However, since 2010, the decreasing trends of fine particles and premature deaths have reversed to increase in the western USA (55% increase in PM2·5, 86% increase in black carbon, and increase of 670 premature deaths [460-810]), while remaining mostly unchanged in the eastern USA. The western USA showed large interannual fluctuations that were attributable to the increasing incidence of wildfires. Furthermore, the black carbon-to-PM2·5 mass ratio increased annually by 2·4% across the USA, mainly due to increasing wildfire emissions in the western USA and more rapid reductions of other components in the eastern USA, suggesting a potential increase in the relative toxicity of PM2·5. 100% of populated areas in the USA have experienced at least one day of PM2·5 pollution exceeding the daily air quality guideline level of 15 µg/m3 during 2000-2020, with 99% experiencing at least 7 days and 85% experiencing at least 30 days. The recent widespread wildfires have greatly increased the daily exposure risks in the western USA, and have also impacted the midwestern USA due to the long-range transport of smoke. INTERPRETATION: Wildfires have become increasingly intensive and frequent in the western USA, resulting in a significant increase in smoke-related emissions in populated areas. This increase is likely to have contributed to a decline in air quality and an increase in attributable mortality. Reducing fire risk via effective policies besides mitigation of climate warming, such as wildfire prevention and management, forest restoration, and new revenue generation, could substantially improve air quality and public health in the coming decades. FUNDING: National Aeronautics and Space Administration (NASA) Applied Science programme, NASA MODIS maintenance programme, NASA MAIA satellite mission programme, NASA GMAO core fund, National Oceanic and Atmospheric Administration (NOAA) GEO-XO project, NOAA Atmospheric Chemistry, Carbon Cycle, and Climate (AC4) programme, and NOAA Educational Partnership Program with Minority Serving Institutions.

Employers' views of the "Healthy Hub Roadshow": a workplace HIV testing intervention in England.

We explored employer uptake and perceptions of workplace human immunodeficiency virus (HIV) testing delivered to employees as part of Healthy Hub Roadshow, a multi-component general health check. Intervention included health checks with tailored advice delivered to 776 employees at 20 events hosted by 11 different workplaces (29 approached, 38% employer uptake). Delivery partners were third sector organisations with significant expertise in HIV testing and support. Health checks included optional HIV test (using 4th generation Insti finger prick rapid tests), Body Mass Index (BMI), blood glucose, blood pressure, and cholesterol. Mixed-methods evaluation included post-event online survey and qualitative interviews with participating employers. Declining employers were invited to complete an online feedback survey. Workplace HIV testing was positively received by all participating organisations, although 78% (14/18) of declining organisations did not provide their reasons for non-participation. Factors of importance to employers included the perceived trustworthiness of delivery partners, being able to provide engaging opportunities for employee health, offering HIV testing as part of a wider health check, and having visible top-level managerial support. Concerns about hosting the events were rare and related to having limited budgets for future events, and the potential loss of productivity related to attendance during work time. Employers indicated that they would not actively seek out workplace HIV testing as part of health promotion efforts, but they were highly receptive to its inclusion in workplace health and wellbeing provision by credible external delivery partners. In conclusion, workplaces are an untapped arena for HIV awareness raising and testing in the UK. Employers should be encouraged and supported to offer opt-in HIV testing as part of a wider workplace health and wellbeing provision for employees.