Contrasting biological potency of particulate matter collected at sites impacted by distinct industrial sources

Association of biological effects in A549 cells with metal content in size-fractionated particles. Cytotoxic potencies according to lactate dehydrogenase (LDH) release and resazurin reduction were regressed against total, water-soluble, and non-water-soluble metals. Pearson product–moment correlation coefficient r-values are presented. LDH release. A) Total metals. UFP, r = 0.77, p = 0.13; PM0.1–2.5, r = −0.55, p = 0.34; PM2.5–10, r = 0.32, p = 0.60; PM>10, r = −0.68, p = 0.21. B) Water-soluble metals. UFP, r = 0.51, p = 0.38; PM0.1–2.5, r = −0.64, p = 0.25; PM2.5–10, r = −0.35, p = 0.57; PM>10, r = −0.68, p = 0.20. C) Non-water-soluble metals. UFP, r = 0.75, p = 0.14; PM0.1–2.5, r = −0.46, p = 0.43; PM2.5–10, r = 0.36, p = 0.55; PM>10, r = −0.68, p = 0.21. Resazurin reduction. D) UFP, r = −0.19, p = 0.76; PM0.1–2.5, r = −0.63, p = 0.26; PM2.5–10, r = −0.60, p = 0.28; PM>10,r = 0.18, p = 0.78. Water-soluble metals. UFP, r = −0.20, p = 0.74; PM0.1–2.5, r = −0.41, p = 0.49; PM2.5–10, r = −0.09, p = 0.88; PM>10, r = 0.04, p = 0.95. Non-water-soluble metals. UFP, r = −0.12, p = 0.84; PM0.1–2.5, r = −0.65, p = 0.24; PM2.5–10, r = −0.62, p = 0.26; PM>10, r = 0.18, p = 0.77. (PDF 43 kb

2-Hydr­oxy-5-nitro­benzaldehyde 2,4-dinitro­phenyl­hydrazone

In the title compound, C13H9N5O7, one of the nitro groups is twisted away from the attached benzene ring by 16.21 (8)°. The dihedral angle between the two benzene rings is 4.63 (1)°. The mol­ecular structure is stabilized by intra­molecular N—H⋯O and O—H⋯N hydrogen bonds which generate an S(6) ring motif. The mol­ecules pack as layers parallel to the ab plane; mol­ecules of adjacent layers are linked into chains along the [101] direction through N—H⋯O hydrogen bonds

Sources of particulate matter components in the Athabasca oil sands region: investigation through a comparison of trace element measurement methodologies

The province of Alberta, Canada, is home to three oil sands regions which, combined, contain the third largest deposit of oil in the world. Of these, the Athabasca oil sands region is the largest. As part of Environment and Climate Change Canada's program in support of the Joint Canada-Alberta Implementation Plan for Oil Sands Monitoring program, concentrations of trace elements in PM2. 5 (particulate matter smaller than 2.5 µm in diameter) were measured through two campaigns that involved different methodologies: a long-term filter campaign and a short-term intensive campaign. In the long-term campaign, 24 h filter samples were collected once every 6 days over a 2-year period (December 2010–November 2012) at three air monitoring stations in the regional municipality of Wood Buffalo. For the intensive campaign (August 2013), hourly measurements were made with an online instrument at one air monitoring station; daily filter samples were also collected. The hourly and 24 h filter data were analyzed individually using positive matrix factorization. Seven emission sources of PM2. 5 trace elements were thereby identified: two types of upgrader emissions, soil, haul road dust, biomass burning, and two sources of mixed origin. The upgrader emissions, soil, and haul road dust sources were identified through both the methodologies and both methodologies identified a mixed source, but these exhibited more differences than similarities. The second upgrader emissions and biomass burning sources were only resolved by the hourly and filter methodologies, respectively. The similarity of the receptor modeling results from the two methodologies provided reassurance as to the identity of the sources. Overall, much of the PM2. 5-related trace elements were found to be anthropogenic, or at least to be aerosolized through anthropogenic activities. These emissions may in part explain the previously reported higher levels of trace elements in snow, water, and biota samples collected near the oil sands operations

Apparent Temperature and Air Pollution vs. Elderly Population Mortality in Metro Vancouver

Background: Meteorological conditions and air pollution in urban environments have been associated with general population and elderly mortality, showing seasonal variation. Objectives: This study is designed to evaluate the relationship between apparent temperature (AT) and air pollution (PM2.5) vs. mortality in elderly population of Metro Vancouver. Methods: Statistical analyses are performed on moving sum daily mortality rates vs. moving average AT and PM 2.5 in 1-, 2-, 3-, 5-, and 7-day models for all seasons, warm temperatures above 15uC, and cold temperatures below 10uC. Results: Approximately 37 % of the variation in all-season mortality from circulatory and respiratory causes can be explained by the variation in 7-day moving average apparent temperature (r 2 = 0.37, p,0.001). Although the analytical results from air pollution models show increasingly better prediction ability of longer time-intervals (r 2 = 0.012, p,0.001 in a 7-day model), a very weak negative association between elderly mortality and air pollution is observed. Conclusions: Apparent temperature is associated with mortality from respiratory and circulatory causes in elderly population of Metro Vancouver. In a changing climate, one may anticipate to observe potential health impacts from the projected high- and particularly from the low-temperature extremes

Publisher Correction To: Disclosure of same-sex practices and experiences of healthcare stigma among cisgender men who have sex with men in five sub-Saharan African countries

An amendment to this paper has been published and can be accessed via the original article

Disclosure of same-sex practices and experiences of healthcare stigma among cisgender men who have sex with men in five sub-Saharan African countries

Background For men who have sex with men (MSM) across sub-Saharan Africa (SSA), disclosure of same-sex practices to family and healthcare workers (HCWs) can facilitate access to HIV prevention services and support, but can also lead to experiences of stigma. Methods We performed mixed-effects regressions on pooled data from MSM in Cameroon, Senegal, Côte d’Ivoire, Lesotho, and eSwatini to assess associations between disclosure and sexual behavior stigma in healthcare contexts; we used logistic regressions to analyze country-specific data. Results Compared to participants who had not disclosed to either family or HCWs, those who had disclosed only to family were more likely to have been gossiped about by HCWs (aOR = 1.70, CI = 1.18, 2.45); the association between having disclosed to family and having felt mistreated in a health center approached, but did not achieve, statistical significance (aOR = 1.56, CI = 0.94, 2.59). Those who had disclosed only to HCWs were more likely to have feared to seek health services (aOR = 1.60, CI = 1.14, 2.25), avoided health services (aOR = 1.74, CI = 1.22, 2.50), and felt mistreated in a health center (aOR = 2.62, CI = 1.43, 4.81). Those who had disclosed to both were more likely to have feared to seek health services (aOR = 1.71, CI = 1.16, 2.52), avoided health services (aOR = 1.59, CI = 1.04, 2.42), been gossiped about by HCWs (aOR = 3.78, CI = 2.38, 5.99), and felt mistreated in a health center (aOR = 3.39, CI = 1.86, 6.20). Country-specific analyses suggested that data from Cameroon drove several of these associations. Conclusions Research to determine the factors driving disclosure’s differential effect on healthcare stigma across contexts is needed. Ultimately, supportive environments enabling safe disclosure is critical to understanding HIV-acquisition risks and informing differentiated HIV-prevention, treatment, and testing services for MSM across SSA

Insights into Elemental Composition and Sources of Fine and Coarse Particulate Matter in Dense Traffic Areas in Toronto and Vancouver, Canada

Traffic is a significant pollution source in cities and has caused various health and environmental concerns worldwide. Therefore, an improved understanding of traffic impacts on particle concentrations and their components could help mitigate air pollution. In this study, the characteristics and sources of trace elements in PM2.5 (fine), and PM10-2.5 (coarse), were investigated in dense traffic areas in Toronto and Vancouver, Canada, from 2015–2017. At nearby urban background sites, 24-h integrated PM samples were also concurrently collected. The PM2.5 and PM10-2.5 masses, and a number of elements (i.e., Fe, Ba, Cu, Sb, Zn, Cr), showed clear increases at each near-road site, related to the traffic emissions resulting from resuspension and/or abrasion sources. The trace elements showed a clear partitioning trend between PM2.5 and PM10-2.5, thus reflecting the origin of some of these elements. The application of positive matrix factorization (PMF) to the combined fine and coarse metal data (86 total), with 24 observations at each site, was used to determine the contribution of different sources to the total metal concentrations in fine and coarse PM. Four major sources were identified by the PMF model, including two traffic non-exhaust (crustal/road dust, brake/tire wear) sources, along with regional and local industrial sources. Source apportionment indicated that the resuspended crustal/road dust factor was the dominant contributor to the total coarse-bound trace element (i.e., Fe, Ti, Ba, Cu, Zn, Sb, Cr) concentrations produced by vehicular exhaust and non-exhaust traffic-related processes that have been deposited onto the surface. The second non-exhaust factor related to brake/tire wear abrasion accounted for a considerable portion of the fine and coarse elemental (i.e., Ba, Fe, Cu, Zn, Sb) mass at both near-road sites. Regional and local industry contributed mostly to the fine elemental (i.e., S, As, Se, Cd, Pb) concentrations. Overall, the results show that non-exhaust traffic-related processes were major contributors to the various redox-active metal species (i.e., Fe, Cu) in both PM fractions. In addition, a substantial proportion of these metals in PM2.5 was water-soluble, which is an important contributor to the formation of reactive oxygen species and, thus, may lead to oxidative damage to cells in the human body. It appears that controlling traffic non-exhaust-related metals emissions, in the absence of significant point sources in the area, could have a pronounced effect on the redox activity of PM, with broad implications for the protection of public health