Into the Holocene, anatomy of the Younger Dryas cold reversal and preboreal oscillation.

During the most recent deglaciation, the upwards trend of warmer Northern Hemisphere (NH) temperatures was punctuated by a rapid and intense return to glacial conditions: the Younger Dryas (YD). The end of this event marks the beginning of the Holocene. Using the University of Toronto version of CCSM4, a model of the climate prior to the YD was created with correct boundary conditions.

Deciphering local and regional hydroclimate resolves contradicting evidence on the Asian monsoon evolution.

The winter and summer monsoons in Southeast Asia are important but highly variable sources of rainfall. Current understanding of the winter monsoon is limited by conflicting proxy observations, resulting from the decoupling of regional atmospheric circulation patterns and local rainfall dynamics. These signals are difficult to decipher in paleoclimate reconstructions.

Highly restricted near-surface permafrost extent during the mid-Pliocene warm period.

Accurate understanding of permafrost dynamics is critical for evaluating and mitigating impacts that may arise as permafrost degrades in the future; however, existing projections have large uncertainties. Studies of how permafrost responded historically during Earth's past warm periods are helpful in exploring potential future permafrost behavior and to evaluate the uncertainty of future permafrost change projections. Here, we combine a surface frost index model with outputs from the second phase of the Pliocene Model Intercomparison Project to simulate the near-surface (~3 to 4 m depth) permafrost state in the Northern Hemisphere during the mid-Pliocene warm period (mPWP, ~3.

Prehistoric human migration between Sundaland and South Asia was driven by sea-level rise.

Rapid sea-level rise between the Last Glacial Maximum (LGM) and the mid-Holocene transformed the Southeast Asian coastal landscape, but the impact on human demography remains unclear. Here, we create a paleogeographic map, focusing on sea-level changes during the period spanning the LGM to the present-day and infer the human population history in Southeast and South Asia using 763 high-coverage whole-genome sequencing datasets from 59 ethnic groups. We show that sea-level rise, in particular meltwater pulses 1 A (MWP1A, ~14,500-14,000 years ago) and 1B (MWP1B, ~11,500-11,000 years ago), reduced land area by over 50% since the LGM, resulting in segregation of local human populations.

Glacial isostatic adjustment: physical models and observational constraints.

By far the most prescient insights into the interior structure of the planet have been provided on the basis of elastic wave seismology. Analysis of the travel times of shear or compression wave phases excited by individual earthquakes, or through analysis of the elastic gravitational free oscillations that individual earthquakes of sufficiently large magnitude may excite, has been the central focus of Earth physics research for more than a century. Unfortunately, data provide no information that is directly relevant to understanding the solid state 'flow' of the polycrystalline outer 'mantle' shell of the planet that is involved in the thermally driven convective circulation that is responsible for powering the 'drift' of the continents and which controls the rate of planetary cooling on long timescales.

Past terrestrial hydroclimate sensitivity controlled by Earth system feedbacks.

Despite tectonic conditions and atmospheric CO levels (pCO) similar to those of present-day, geological reconstructions from the mid-Pliocene (3.3-3.0 Ma) document high lake levels in the Sahel and mesic conditions in subtropical Eurasia, suggesting drastic reorganizations of subtropical terrestrial hydroclimate during this interval.

Three Years of High Time-resolution Air Pollution Monitoring in the Complex Multi-source Harbor of New York and New Jersey.

In densely developed port areas with numerous emissions sources, relating measured air quality changes to emissions is challenging given the geographic density of sources without unique pollutant composition signatures. To better understand air quality during increasing emission controls at the Port of New York and New Jersey ("Port"), an air monitoring station was sited to minimize collinearity of sources along ordinal directions. The study area includes an international airport, interstate highway, port terminals and shipping lanes, and industrial sources, as well as typical urban emissions of a megacity.

Wood smoke black carbon from Indigenous traditional cultural activities in a subarctic Cree community.

Indoor concentrations of black carbon (BC) were measured when wood was burned for traditional cultural activities in a study in a Cree community located in subarctic Canada. The study also included an intervention using a propane-fuelled heater to mitigate in situ BC. Mass concentrations of BC were measured in a game-smoking tent for 39 days and in hunting cabins on the west coast of James Bay, Canada, for 8 days.

Drier tropical and subtropical Southern Hemisphere in the mid-Pliocene Warm Period.

Thermodynamic arguments imply that global mean rainfall increases in a warmer atmosphere; however, dynamical effects may result in more significant diversity of regional precipitation change. Here we investigate rainfall changes in the mid-Pliocene Warm Period (~ 3 Ma), a time when temperatures were 2-3ºC warmer than the pre-industrial era, using output from the Pliocene Model Intercomparison Projects phases 1 and 2 and sensitivity climate model experiments. In the Mid-Pliocene simulations, the higher rates of warming in the northern hemisphere create an interhemispheric temperature gradient that enhances the southward cross-equatorial energy flux by up to 48%.

Addressing decontaminated respirators: Some methods appear to damage mask integrity and protective function.

Decontamination of N95 respirators is being used by clinicians in the face of a global shortage of these devices. Some treatments for decontamination, such as some vaporized hydrogen peroxide methods or ultraviolet methods, had no impact on respiratory performance, while other treatments resulted in substantial damage to masks.

Mobile monitoring of air and noise pollution in Philadelphia neighborhoods during summer 2017.

Mobile monitoring is a useful approach for measuring intra-urban variation of air pollution in urban environments. In this study, we used a mobile monitoring approach to study the spatial-temporal variability of air and noise pollution in urban neighborhoods of Philadelphia. During summer 2017, we used portable instruments to measure PM, black carbon (BC), and noise levels along 5 km paths in four residential neighborhoods (Tioga, Mill Creek, Chestnut Hill, and Northern Liberties) and one commercial district (Center City) in Philadelphia, Pennsylvania, USA.

Associations between Indoor Air Pollution and Acute Respiratory Infections among Under-Five Children in Afghanistan: Do SES and Sex Matter?

: Low-income families often depend on fuels such as wood, coal, and animal dung for cooking. Such solid fuels are highly polluting and are a primary source of indoor air pollutants (IAP). We examined the association between solid fuel use (SFU) and acute respiratory infection (ARI) among under-five children in Afghanistan and the extent to which this association varies by socioeconomic status (SES) and gender.

Roadside Exposure and Inflammation Biomarkers among a Cohort of Traffic Police in Kathmandu, Nepal.

Air pollution is a major environmental problem in the Kathmandu Valley. Specifically, roadside and traffic-related air pollution exposure levels were found at very high levels exceeding Nepal air quality standards for daily PM. In an exposure study involving traffic police officers, we collected 78 blood samples in a highly polluted spring season (16 February 2014⁻4 April 2014) and 63 blood samples in the less polluted summer season (20 July 2014⁻22 August 2014).

Exposure to air pollutants in Vietnam: Assessing potential risk for tourists.

Tourism can form an important component of a nation's GDP, and Vietnam is among the most visited countries in Southeast Asia. Most studies on personal exposure focus on the general population, or occupational cohorts with exposure to specific pollutants. However, short-term exposure to air pollutants while visiting regions with high levels of air pollution can lead to acute health effects.

PM exposure in highly polluted cities: A case study from New Delhi, India.

Personal exposure (PE) to air pollutants is driven by a combination of pollutant concentrations in indoor and outdoor environments, and time-activity pattern of individuals. The objectives of this study were to estimate personal exposure to PM and black carbon (BC), and assess the representability of ambient air quality monitoring stations to serve as surrogates for PE in New Delhi. Personal exposure to air pollutants (PM and BC) was measured using portable, battery-operated instruments (PM- pDR1500 and BC- microAethalometer AE51) in a small cohort of healthy adults (n=12 in summer, n=6 in winter) with no occupational exposure.

Effects of hookah smoking on indoor air quality in homes.

Introduction: Hookahs (water pipes) are rapidly increasing in popularity worldwide. Evidence suggests that although perceived as safer than cigarette smoke, hookah smoke may be as, or even more, dangerous as cigarette smoke.

Methods: Air samples from 33 homes-11 where only hookah-smoking occurred, 12 with only cigarettes and 10 with no smoking-were collected to analyse concentrations of particulate matter (PM), black carbon, elemental and organic carbon and carbon monoxide (CO).

Exposure science in an age of rapidly changing climate: challenges and opportunities.

Climate change is anticipated to alter the production, use, release, and fate of environmental chemicals, likely leading to increased uncertainty in exposure and human health risk predictions. Exposure science provides a key connection between changes in climate and associated health outcomes. The theme of the 2015 Annual Meeting of the International Society of Exposure Science-Exposures in an Evolving Environment-brought this issue to the fore.

Evaluating the efficacy of cloth facemasks in reducing particulate matter exposure.

Inexpensive cloth masks are widely used in developing countries to protect from particulate pollution albeit limited data on their efficacy exists. This study examined the efficiency of four types of masks (three types of cloth masks and one type of surgical mask) commonly worn in the developing world. Five monodispersed aerosol sphere size (30, 100, and 500 nm, and 1 and 2.

Respiratory Effects of High Levels of Particulate Exposure in a Cohort of Traffic Police in Kathmandu, Nepal.

Objectives: To investigate the traffic-related PM2.5 and black carbon (BC) exposures and assess their health effects.

Methods: Personal exposure to PM2.

Exposure to particulate matter in India: A synthesis of findings and future directions.

Air pollution poses a critical threat to human health with ambient and household air pollution identified as key health risks in India. While there are many studies investigating concentration, composition, and health effects of air pollution, investigators are only beginning to focus on estimating or measuring personal exposure. Further, the relevance of exposures studies from the developed countries in developing countries is uncertain.

Repeated measures of inflammation, blood pressure, and heart rate variability associated with traffic exposures in healthy adults.

Background: Previous human exposure studies of traffic-related air pollutants have demonstrated adverse health effects in human populations by comparing areas of high and low traffic, but few studies have utilized microenvironmental monitoring of pollutants at multiple traffic locations while looking at a vast array of health endpoints in the same population. We evaluated inflammatory markers, heart rate variability (HRV), blood pressure, exhaled nitric oxide, and lung function in healthy participants after exposures to varying mixtures of traffic pollutants.

Methods: A repeated-measures, crossover study design was used in which 23 healthy, non-smoking adults had clinical cardiopulmonary and systemic inflammatory measurements taken prior to, immediately after, and 24 hours after intermittent walking for two hours in the summer months along three diverse roadways having unique emission characteristics.

Mining in subarctic Canada: airborne PM2.5 metal concentrations in two remote First Nations communities.

Airborne particulate matter arising from upwind mining activities is a concern for First Nations communities in the western James Bay region of Ontario, Canada. Aerosol chemical components were collected in 2011 from two communities in northern Ontario. The chemical and mass concentration data of particulate matter collected during this study shows a significant difference in PM2.