作者: Bair, Salix ; Claassen, Matthew ; Arnott, W. Patrick ; Meyer, Marit E. ; Watson, John G. ; Fortenberry, Claire ; Wang, Xiaoliang ; Bingham, Bjoern ; Chow, Judith C.

Fire is an imminent risk in space activities.Toxic gas and particle emissions can quickly reach dangerous levels in sealed environments.To improve smoke detection, protection, and post-fire cleanup, understanding the emissions from the pyrolysis of spacecraft-relevant materials is crucial.This study investigated the pyrolysis of four common spacecraft materials, including Kapton, polytetrafluoroethylene (PTFE), Teflon/Kapton/Teflon (TKT) wire insulation, and Velcro, to identify, evaluate, and quantify their gaseous and particulate emissions.Kapton emitted high levels of carbon monoxide and hydrogen cyanide, PTFE and TKT emitted multiple toxic fluorine-based gases including carbonyl fluoride and hydrogen fluoride, while Velcro had the highest PM_2.5 emission factor.Most particles were in the submicron size range, with mode diameter peaked in the 100-200 nm range.The particles were nearly elec. neutral, carrying less than 0.15 net elementary charges per particle.Organic compounds predominated in the particle compositions

2025-05-01·Environmental Pollution

Latitudinal gradients of snow contamination in the Rocky Mountains associated with anthropogenic sources

Article

作者: McConnell, Joseph R ; Choma, Nicole ; Schwan, Melissa R ; Gleason, Kelly E ; Weisberg, Peter J ; Dunham-Cheatham, Sarrah M ; Sexstone, Graham A ; Gustin, Mae Sexauer ; Arienzo, Monica M ; Csank, Adam

Seasonal snow is an important source of drinking water and recreation, and for agriculture in the Rocky Mountain region. Monitoring snow-water quality can inform on the effects to the albedo and energy balance of the snowpack, and the sources of natural and anthropogenic aerosol and gases. This study analyzed metals in the seasonal snowpack from water year (WY) 2018 for 49 sites. Calcium, lanthanum, and cerium concentrations support the importance of mineral dust to the southern Rocky Mountains. Mercury (Hg), zinc (Zn), and cadmium (Cd) concentrations showed a similar spatial pattern to mineral dust, whereas antimony (Sb) concentrations were highest in the northern Rocky Mountains. To assess the relative contributions from dust versus anthropogenic contaminant sources, enrichment factors (EF) were calculated, with values above 10 indicating anthropogenic contamination. For Cd, Hg, Sb, and Zn, EF values exceeded 10 at northern sites. These observations were compared to spatial trends of EF values of Hg from WY2009 to WY2018, regional monitoring networks, and back trajectory analyses. The agreement between these datasets revealed temporally consistent contaminant sources and/or transport processes to the northern Rocky Mountains snowpack. Sources include current and historical mining and smelting in the region. Strategies to limit the emissions of these metals to the Northern Rockies could benefit from focusing on remediation of contaminated sites, and continued monitoring and mitigation of active mining and smelting.

2025-05-01·Journal of Environmental Sciences

Impacts of emission reduction and meteorological conditions on air quality improvement from 2016 to 2020 in the Northeast Plain, China

Article

作者: Wang, Qiyuan ; Yang, Xueling ; Liu, Lang ; Xie, Hailing ; Cao, Yue ; Wang, Luyao ; Ho, Steven Sai Hang ; Tian, Jie

The Northeast Plain in China ranks among the top five regions that have been significantly impacted by haze pollution. To effectively control pollution, it is crucial to accurately assess the effects of emission reduction measures. In this study, we analyzed surveillance data and found substantial decreases (ranging from 19.0% to 50.1%) in average annual mass concentrations of key pollutants (such as CO, SO₂, NO₂, and PM_2.5) in the Northeast Plain from 2016 to 2020. To precisely determine the contributions of meteorological conditions and emission reductions to the improvement of air quality in the Northeast Plain, we conducted three scenario simulations. By comparing source emissions in December 2016 and 2020 using the WRF-Chem model (except for SO₂), we observed significant reductions of 21.3%, 8.8%, and 9.8% in mass concentrations of PM_2.5, NO₂, and CO, respectively, from 2016 to 2020. This highlights the essential role that meteorological conditions play in determining air quality in the Northeast Plain. Moreover, further reducing source emissions by 30% in December 2016 resulted in subsequent reductions of 25.3%, 29.0%, 4.5%, and 30.3% in mass concentrations of PM_2.5, SO₂, NO₂, and CO, respectively, under the same meteorological conditions. Notably, source emission reduction was effective for PM_2.5, SO₂, and CO, but not for NO₂. The improvement in air quality in the Northeast Plain from 2016 to 2020 can be attributed to the combined effects of improved meteorological conditions and reduced pollution sources.

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