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At US-Mexico border Ports of Entry, vehicles idle for long times waiting to cross northbound into the US. Long wait times at the border have mainly been studied as an economic issue, however, exposures to emissions from idling vehicles can also present an exposure risk. Here we present the first data on in-vehicle exposures to driver and passengers crossing the US-Mexico border at the San Ysidro, California Port of Entry (SYPOE). Participants were recruited who regularly commuted across the border in either direction and told to drive a scripted route between two border universities, one in the US and one in Mexico. Instruments were placed in participants' cars prior to commute to monitor-1-minute average levels of the traffic pollutants ultrafine particles (UFP), black carbon (BC) and carbon monoxide (CO) in the breathing zone of drivers and passengers. Location was determined by a GPS monitor. Results reported here are for 68 northbound participant trips. The highest median levels of in-vehicle UFP were recorded during the wait to cross at the SYPOE (median 29,692 particles/cm 3 ) significantly higher than the portion of the commute in the US (median 20,508 particles/cm 3 ) though not that portion in Mexico (median 22, 191 particles/cm 3 ). In-vehicle BC levels at the border were significantly lower than in other parts of the commute. Our results indicate that waiting in line at the SYPOE contributes a median 62.5% (range 15.5%–86.0%) of a cross-border commuter's exposure to UFP and a median 44.5% (range (10.6–79.7%) of exposure to BC inside the vehicle while traveling in the northbound direction. Reducing border wait time can significantly reduce in-vehicle exposures to toxic air pollutants such as UFP and BC, and these preventable exposures can be considered an environmental justice issue. [ABSTRACT FROM AUTHOR]

[Display omitted] • Analysis of long-term exposure to PM 2.5 major components and overall mortality among the elderly in the southeastern United States. • A large-scale population-based cohort study by leveraging fine-resolution PM 2.5 components data and the Medicare population. • We observed elevated all-cause mortality associated with long-term exposure to black carbon, organic matters, nitrate, and soil particles. • Better understanding of component-specific effects of PM 2.5 on all-cause mortality could inform pollution control policies on specific sources. Long-term exposure to fine particulate matter (PM 2.5) mass has been associated with adverse health effects. However, the health effects of PM 2.5 components have been less studied. There is a pressing need to better understand the relative contribution of components of PM 2.5 , which can lay the scientific basis for designing effective policies and targeted interventions. We conducted a population-based cohort study, comprising all Medicare enrollees aged 65 or older in the southeastern United States from 2000 to 2016, to explore the associations between long-term exposure to PM 2.5 major components and all-cause mortality among the elderly. Based on well-validated prediction models, we estimated ZIP code-level annual mean concentrations for five major PM 2.5 components, including black carbon (BC), nitrate (NIT), organic matter (OM), sulfate (SO 4), and soil particles. Data were analyzed using Cox proportional hazards models, adjusting for potential confounders. The cohort comprised 13,590,387 Medicare enrollees and a total of 107,191,652 person-years. In single-component models, all five major PM 2.5 components were significantly associated with elevated all-cause mortality. The hazard ratios (HR) per interquartile range (IQR) increase in exposure were 1.027 (95% CI: 1.025–1.030), 1.012 (95% CI: 1.010–1.013), 1.018 (95% CI: 1.017–1.020), 1.021 (95% CI: 1.017–1.024), and 1.004 (95% CI: 1.003–1.006) for BC, NIT, OM, SO 4 , and soil particles, respectively. While the effect estimate of soil component was statistically significant, it is much smaller than those of combustion-related components. Our study provides epidemiological evidence that long-term exposure to major PM 2.5 components is significantly associated with elevated mortality. [ABSTRACT FROM AUTHOR]

The current technologies to treat hypersaline produced water (PW), such as thermal evaporation, are usually energy-intensive and cost-prohibitive. This study developed a low-cost, robust, solar-driven carbon black and airlaid paper-based evaporator (CAPER) for desalination of PW in the Permian Basin, United States. The study aims to better understand the removal of aromatic organic compounds and heavy metals during solar distillation, water output, and heat transfer. Outdoor experiments using CAPER assisted with polystyrene foam in a single slope, single basin solar still achieved an enhanced average evaporation rate of 2.23 L per m2 per day, 165% higher than that of a conventional solar still. Analysis of heat transfer models demonstrated that CAPER solar evaporation achieved an evaporative heat transfer coefficient of ∼28.9 W m−2·K−1, 27.9% higher than without CAPER. The maximum fractional energy of evaporation and convection heat transfer inside the solar still with and without CAPER was ∼81.4% and ∼78.2%, respectively. For the PW with a total dissolved solids concentration of 134 g L−1, solar distillation removed 99.97% salts and over 98% heavy metals. The high removal efficiency of 99.99% was achieved for Ca, Na, Mg, Mn, Ni, Se, Sr, and V. Organic characterization revealed that solar distillation removed over 83% aromatic compounds. Solar desalination using CAPER provides a low-cost and high-performance process to treat PW with high salinity and complex water chemistry for potential fit-for-purpose beneficial uses. Image 1 • A carbon black and airlaid paper-based solar evaporator (CAPER) was developed. • Outdoor distillation of produced water (PW) achieved evaporation of 2.23 L m−2·d−1. • The evaporation rate of PW with CAPER is 165% higher than without CAPER. • Heat transfer coefficient with CAPER is 27.9% higher than without CAPER. • 99.97% salts, 98% metals, >83% aromatic compounds removed from 134 g L−1 TDS PW. [ABSTRACT FROM AUTHOR]