Time-weighted Average Research Articles

Membrane-Based Portable Colorimetric Gaseous Chlorine Sensing Probe.

Highly toxic chlorine gas imposes serious health risks in the workplace. The ability to on-site, real-time monitoring of instantaneous and time-weighted average (TWA) chlorine gas concentrations in a simple, sensitive, accurate, and reliable manner would be highly beneficial to improve workplace health and safety. Here, we propose and experimentally validate a gaseous chlorine detection principle based on a N,N-diethyl-p-phenylenediamine sulfate salt/Cl2 colorimetric reaction-controlled membrane process to regulate the gaseous chlorine transport across a gas-permeable membrane that enables the establishment of a time-resolved analytical relationship to quantify chlorine concentration by multidata points with dramatically enhanced accuracy and reliability. A gas-permeable membrane-based portable colorimetric gaseous chlorine sensing probe (MCSP) was designed and fabricated. The MCSP embedded the proposed analytical principle that is capable of real-time continuous monitoring of the instantaneous and TWA chlorine gas concentrations within an analytical range of 0.009-2.058 mg L-1 without the need for on-going calibration, which could be a useful analytical tool for managing the toxic chlorine gas-imposed health risks in workplaces.

Assessment of Noise Pollution of Kolkata Metro Railway System and Its Impact on Urban Receptors A Case Study

An assessment of noise quality was conducted at underground and overground metro stations, within the metro rakes (AC and Non-AC) and at an institutional building near elevated metro corridor to assess the exposure of Kolkata Metro Railway System. The present study was conducted in different hours (peak and non-peak hour) for different types of rake (AC and Non-AC) movement. Different noise descriptors including A-weighted equivalent noise (Leq), statistical noise (L10,L50,L90), noise climate (NC), traffic noise index (TNI), two hour noise dose (%ND) and corresponding time-weighted average (TWA) were calculated under the purview of the present study. Pearson’s correlation was performed between all noise descriptors to investigate the relation between them. Scatter plot analysis was conducted between L10 and %ND. In case of all study duration, all noise descriptors mostly exceeded FTA prescribed noise standard, along with 2-hr TWA which exceeded the OSHA guidelines of 100 dB for both AC and Non-AC rakes. On the other hand, at underground and overground metro stations, within metro rakes (except at day peak hour within AC coach) and at school building, mean value of traffic noise index (TNI) exceeded 74 dB (A), the threshold of over criterion. The study results indicate that Non-AC rakes are more annoying than AC-rakes. In all the study units, Leq was influenced by L10, which originates from pressure honking. There is very strong relationship observed between L10 and % ND. This study proposes that noise barrier should be installed at underground and overground metro stations, along the stretches of overground metro track, within metro rakes for developing the acoustic quality of Kolkata Metro Railway System and the areas of its immediate vicinity.

Musculoskeletal complications of hand–arm vibration syndrome among tyre shop workers in Kelantan, Malaysia

Objectives. Exposure to hand–arm vibration (HAV) is associated with hand–arm vascular syndrome (HAVS), which is characterized by musculoskeletal complications. However, evidence on this matter has been inconclusive. Therefore, this study aimed to determine and compare the prevalence of musculoskeletal complications of HAVS between a high-exposure (≥5 m·s−2) group and a low–moderate-exposure (<5 m·s−2) group and to explore the factors associated with the musculoskeletal complications of HAVS among tyre shop workers in Kelantan, Malaysia. Methods. A cross-sectional study involving 200 tyre shop workers was carried out. HAV was measured by a vibration meter. The workers were divided into two exposure groups – according to their 8-h time-weighted average, A(8), of vibration exposure – and compared. Results. Almost half of the workers reported musculoskeletal complications of the upper limbs and neck. Only the lifetime vibration dose (LVD) was significantly associated with the development of musculoskeletal complications. Conclusion. The high-exposure group had a higher prevalence of musculoskeletal complications. Only the LVD was significantly associated with complications. However, all factors of the work system, such as ergonomics, handgrip force and posture, might contribute to the development of musculoskeletal complications of HAVS and should be included in assessments.

Characterization of occupational smoke exposure among wildland firefighters in the midwestern United States

Wildland firefighters are repeatedly exposed to elevated levels of wildland fire smoke (WFS) while protecting lives and properties from wildland fires. Studies reporting personal exposure concentrations of air pollutants in WFS during fire suppression or prescribed burn activities have been geographically limited to the western and southeastern United States. The objective of this study is to characterize exposure concentrations of air pollutants in WFS emissions among wildland firefighters who conducted prescribed burns in the Midwest. Between 2016 and 2019, a total of 35 firefighters (31 males and 4 females, age of 35.63 ± 9.31 years) were recruited to participate in this study. Personal particulate matter 2.5 (PM2.5) and carbon monoxide (CO) exposure concentrations were measured during prescribed burns. The level of black carbon (BC) in WFS particulates was determined using the light transmission technique, while trace metal composition was analyzed using inductively coupled plasma mass spectrometry (ICP-MS). The results showed geometric means for PM2.5, CO, and BC concentrations were 1.43 ± 0.13 mg/m3, 7.02 ± 0.69 ppm, and 58.79 ± 5.46 μg/m3, respectively. Although no occupational exposure limits (OELs) were exceeded by 8-h time-weighted average (TWA) exposure concentration observed in the firefighters, a total of 28 personal CO exposure concentrations were above the National Institute for Occupational Safety and Health (NIOSH) Recommended Exposure Limit (REL) Ceiling (200 ppm) for CO. PM2.5 and CO concentrations were about 2–7 times higher in the Midwest than the other regions. Firefighters who performed holding had higher CO exposure concentrations compared to firefighters who performed lighting (p < 0.01), while lighters were exposed to higher level of BC in the smoke particulates (p < 0.01), possibly due to the domination of exposure by different combustion sources and stages. The levels of trace metals in WFS particulates were well below the corresponding OELs and no task-related difference was observed except for manganese. Our results suggest that wildland firefighters in the midwestern region have higher WFS exposures while working at prescribed burns compared to those western and southeastern United States.

Nanoparticle Exposure and Workplace Measurements During Processes Related to 3D Printing of a Metal Object.

Metal 3D printing has many potential uses within prototyping and manufacturing. Selective laser melting (SLM) is a process that uses metal powders in the micrometer range as printing material. The particle release from the entire SLM printing process is not well-studied. While the 3D printing itself often occurs in a sealed chamber, activities related to the process can potentially release harmful metal particles to the indoor working environment through resuspension of the printing powder or via incident nanoparticles generated during printing. The objective of this study was to improve the understanding of particle exposure in work processes associated with 3D printing and potential needs for interventions by a case study conducted in a 3D printing facility. In this setting, direct release and dispersion of particles throughout the workspace from processes related to metal 3D printing was investigated. The release from five activities were studied in detail. The activities included post-printing cleaning, object annealing, and preparation of new base substrate for the next printing was. Three of the five measured activities caused particles number concentrations in the working environment to increase above background levels which were found to be 8·102 cm−3. Concentrations during chamber emptying and the open powder removal system (PRS) cleaning processes increased to 104 and 5·103 cm−3, respectively, whereas grinding activity increased number concentrations to 2.5·105 cm−3. Size distributions showed that particles were mainly smaller than 200 nm. Respirable mass concentrations were 50.4 μg m−3, collected on filters. This was corroborated by respirable mass measured with a DustTrak of 58.4 μg m−3. Respirable mass concentrations were below the occupational exposure limits in Denmark for an 8 h time-weighted average.

Abstract 348: Impact of Low and High Partial Pressure of Carbon Dioxide on Neuron Specific Enolase Derived from Serum and Cerebrospinal Fluid in Patients Who Underwent Targeted Temperature Management After Out-of-hospital Cardiac Arrest: A Retrospective Study

Aim: In a previous study, low and high-normal arterial carbon dioxide tension (PaCO 2 ) were not associated with serum neuron specific enolase (NSE) in cardiac arrest survivors. We assessed the effect of PaCO 2 on NSE in cerebrospinal fluid (CSF) and serum. Methods: This was a retrospective study. PaCO 2 for the first 24 h was analysed in four means, qualitative exposure state (qES), time-weighted average (TWA), median, and minimum-maximum (Min-Max). These subgroups were divided into low (LCO 2 ) and high PaCO 2 (HCO 2 ) groups defined as PaCO 2 ≤35.3 and PaCO 2 &gt;43.5 mmHg, respectively. NSE was measured at 24, 48, and 72 h (sNSE 24,48,72 and cNSE 24,48,72 ) from return of spontaneous circulation (ROSC). The primary outcome was the association between PaCO 2 and the NSE measured at 24 h after ROSC. Results: Forty-two subjects (male, 33; 78.6%) were included in total cohort. PaCO 2 in TWA subgroup was associated with cNSE 24,48,72 , while PaCO 2 in the other subgroup were only associated with cNSE 24 . PaCO 2 and cNSE in qES subgroup showed good correlation (r= -0.61; p&lt; 0.01), and in TWA, Median, and Min-Max subgroup showed moderate correlations (r= -0.57, r= -0.48, and r= -0.60; p&lt; 0.01). Contrastively, sNSE was not associated and correlated with PaCO 2 in all analysis. Poor neurological outcome in LCO 2 was significantly higher than HCO 2 in qES, TWA, and Median subgroups ( p&lt; 0.01, p&lt; 0.01, and p= 0.02). Conclusion: Association was found between NSE and PaCO 2 using CSF, despite including normocapnic ranges; TWA of PaCO 2 may be most strongly associated with CSF NSE levels. A prospective, multi-centre study is required to confirm our results.

Impacts of electronic cigarettes usage on air quality of vape shops and their nearby areas

With the rapid growth of the electronic cigarette (e-cig) market, there is an increasing number of vape shops that exclusively sell e-cigs. The use of e-cigs in the vape shop is a primary source of indoor particles, which might transport to its nearby indoor spaces in the multiunit setting. In this study, six pairs of vape shops and neighboring businesses in Southern California were recruited for real-time measurements of particulate pollutants between February 2017 and October 2019. The mean (SD) particle number concentration (PNC) and PM2.5 concentration in the studied vape shops were 2.8 × 104 (2.3 × 104) particles/cm3 and 276 (546) μg/m3, which were substantially higher than those in neighboring businesses and outdoor areas. In addition, 24-h time-weighted average (TWA) nicotine sampling was conducted in the six pairs and three additional pairs. Nicotine was detected in the air of all the studied vape shops and neighboring businesses, in which the mean (SD) concentration was 2.59 (1.02) and 0.17 (0.13) μg/m3, respectively. Inside vape shops, the dilution-corrected vaping density (puffs/h/100 m3) is a strong predictor of the particle concentration, and nicotine concentration highly depends on the air exchange rate (AER). Out of the six studied pairs, PNCs in five vape shops and PM2.5 in two vape shops were significantly correlated with those in their neighboring businesses. This correlation was stronger when the door of the vape shop was closed. When the door was open, environmental electronic vaping (EEV) aerosols, especially smaller particles, could transport from the vape shop to the outdoor environment. Overall, e-cig usage in the vape shop impacts both its own and nearby air quality, raising concerns regarding the risk of exposure to EEV aerosols in the surrounding environments.

Early-life air pollution exposure and biomarkers of systemic inflammation in young children

Background/Aims. Air pollution exposure has been associated with adverse health effects in children. Although the exact underlying mechanisms are not clarified, systemic inflammation may play a role in pollution-induced health effects. This study aimed to investigate inflammatory markers in children in relation to early-life air pollution exposure. Methods. We measured 92 inflammatory markers in plasma samples collected at ages 6 months, 1 and 2 years from healthy children residing in Stockholm, Sweden (n=108), using Olink Proteomics (Uppsala, Sweden). Residential time-weighted average (TWA) outdoor exposure to particulate matter with an aerodynamic diameter of &lt;10 μm (PM10) and &lt;2.5 μm (PM2.5), black carbon (BC), nitrogen oxides (NOx) and nitrogen dioxide (NO2) from birth up to age 6 months was estimated by dispersion modeling. Age-specific associations between TWA air pollution exposures and inflammatory markers were investigated using linear regression with inclusion of potential confounding variables. Further, we applied linear mixed-effect models to analyze the temporal patterns of biomarkers during the first 2 years of life in relation to early-life air pollution exposure. Multiple comparisons were accounted for using False Discovery Rate (FDR 5%) adjustment. Results. At age 1 year, tumor necrosis factor (TNF) and chemokine ligand 9 (CXCL9) were inversely associated with TWA exposure to NO2, NOx, and BC (FDR p-value&lt;0.05). However, no clear association was found at ages 6 months or 2 years. In the mixed models, only TNF was associated with NO2, NOx, and BC, but the associations were not significant after adjustment for multiple testing. Conclusions: Our findings suggest that air pollution exposure during the first 6 months of life is related to certain markers of systemic inflammation in children at age 1 year. These markers may be involved in biological processes through which air pollution exposure may modulate systemic inflammation in infants.

Evaluation of 4D-MRI Guided Liver SBRT on the MR-Linac

MR-Linac provide soft-tissue contrast, enabling direct visualization of liver lesions during treatment with the potential to increase SBRT precision. Imaging, however, is hampered by breathing motion. We therefore developed a 4D-MRI guided liver SBRT workflow, which is in clinical use since October 2019. The purpose of this study was to evaluate this motion management strategy and toxicity in the first cohort of patients. Eight patients with 10 liver oligometastases received 4D-MRI guided liver SBRT, after signing informed consent. For each patient, a mid-position (midP) planning CT was derived from a 4D-CT. An SBRT plan was created on the midP-CT (step-and-shoot IMRT, 15 beams, 3x20 Gy), with a patient-specific anisotropic PTV margin tailored to the respiratory tumor amplitude in the 4D-CT. On the MR-Linac, a daily 4D-MRI (multi 2D TSE, TE/TR = 60/316 ms, 25 slices, 2x2x5mm3, 30 repetitions, 4min) was acquired. In each 4D-MRI phase, the tumor was loco-rigidly registered to the midP-CT. The time-weighted average of the 10 resulting registrations was applied to adapt the treatment plan, using adapt-to-position with segment-weights optimization. Before irradiation, a new 4D-MRI was used to visually verify if the tumor was still accurately aligned. Additional adaptions were applied if needed. During irradiation, motion monitoring was performed by repetitive acquisition and visual inspection of 4D-MRI scans. The time of the patient in the treatment room was recorded. The tumor in all 4D-MRI scans was retrospectively registered to the midP-CT to quantify intra-fraction mid-position and peak-to-peak amplitude variability. Additionally, acute toxicity was reported. With our 4D-MRI guided workflow, all lesions were visible prior and during treatment. No additional fiducial markers were required for guidance. Treatment times were available for 12 fractions with a median (IQR) of 45 (41 – 50) minutes. Median daily tumor misalignment before plan adaption was 2.6 (-6.5 – 10.6) mm (LR), 4.2 (-6.2 – 17.7) mm (CC) and -0.3 (-4.5 – 4.1) mm (AP). 4D-MRI tumor amplitude was 4.0 (2.5 – 5.9) mm (LR), 14.9 (10.8 – 23.7) mm (CC) and 6.6 (2.2 – 13.9) mm (AP). The intra-fraction tumor mid-position group mean (M), systematic (Σ) and random (σ) deviations were M = 0.2, Σ = 1.7, σ = 1.9 mm (LR), M = 3.6, Σ = 2.9, σ = 2.9 (CC) and M = -2.0, Σ = 1.5 σ = 2.5 mm (AP). Tumor amplitude variability with respect to the midP-CT was M = 1.4, Σ = 1.7, σ = 1.7 mm (LR), M = -5.0, Σ = 6.1, σ = 3.6 (CC) and M = -0.4, Σ = 4.0 σ = 3.5 mm (AP). Grade 2 toxicity (fatigue and nausea) was observed in four patients, with a median (IQR) follow up time of 36 (15 – 51) days. 4D-MRI guided liver SBRT was successfully delivered to our first cohort of 8 patients, providing image guidance without marker implantation. Median treatment time was 45 minutes. Considerable intra-fraction position and amplitude variability stress the need for intra-fraction motion management strategies, such as trailing. No grade ≥3 toxicity was observed.

Whole-body heat exchange in women during constant- and variable-intensity work in the heat.

Time-weighted averaging is used in occupational heat stress guidelines to estimate the metabolic demands of variable-intensity work. However, compared to constant-intensity work of the same time-weighted average metabolic rate, variable-intensity work may cause decrements in total heat loss (dry + evaporative heat loss) that exacerbate heat storage in women. We therefore used direct calorimetry to assess whole-body total heat loss and heat storage (metabolic heat production minus total heat loss) in women and men during constant- and variable-intensity work of equal average intensity. Ten women [mean (SD); 31 (11) years] and fourteen men [30 (8) years] completed two trials involving 90-min of constant- and variable-intensity work (cycling) eliciting an average metabolic heat production of ~ 200W/m2 in dry-heat (40°C, ~ 15% relative humidity). External work was fixed at ~ 40W/m2 for constant-intensity work, and alternated between ~ 15 and ~ 60W/m2 (5-min each) for variable-intensity work. When expressed as a time-weighted average over each work period, total heat loss did not differ between men and women (mean difference [95% CI]; 4W/m2 [-11, 20]; p = 0.572) or between constant- and variable-intensity work (1W/m2 [-3, 5]; p = 0.642). Consequently, heat storage did not differ significantly between men and women (-4W/m2 [-17, 8]; p = 0.468) or between constant- and variable-intensity work (0W/m2 [-3, 3]; p = 0.834). Neither whole-body heat loss nor heat storage was modulated by the partitioning of work intensity, indicating that time-weighted averaging is appropriate for estimating metabolic demand to assess occupational heat stress in women.

Occupational exposure to inorganic lead and its compounds in Romania

Abstract Lead and its compounds are hazardous chemical agents; some lead compounds, are classified as carcinogens in humans. In Romania, the occupational exposure to inorganic lead and its compounds occurs in many sectors: production of lead, manufacture of batteries, manufacture of thermal ceramic products (terracotta), production of electric and electronic components, manufacture of articles of metal wire, production of dyes and additives for plastics, recovery of lead from waste batteries, waste collection and treatment of electrical and electronic equipment, etc. The binding occupational limit value for inorganic lead compounds established under the national regulations is 0.15 mg/m3 in the air (measured in relation to a reference period of eight hours, time-weighted average, TWA). The binding biological limit value is 70 μg Pb/100 ml blood. We have summarized lead occupational exposure data collected from the regional public health authorities in Romania, for the period 2011-2019. The concentrations of lead recorded in the workplaces air varied between “not detected” and 0.22 mg/m3. The lead concentrations in the blood had high values (over the alert value of 40 μg/100 ml blood) in several activities (production of lead, recovery-recycling of lead from waste batteries, manufacture of batteries, and manufacture of articles of metal wire) leading to the need of continuous surveillance of health status for the exposed workers.

Pulse pressure during the initial resuscitative period in patients with septic shock treated with a protocol-driven resuscitation bundle therapy.

Background/AimsMaintaining a mean arterial pressure (MAP) ≥ 65 mmHg during septic shock should be based on individual circumstances, but specific target is poorly understood. We investigated associations between time-weighted average (TWA) hemodynamic parameters during the initial resuscitative period and 28-day mortality.MethodsProspectively collected data were obtained from a septic shock patient registry, according to the Sepsis-3 definition, between 2016 and 2018. The TWA systolic blood pressure, diastolic blood pressure, MAP, shock index, and pulse pressure (PP) during the first 6 hours after shock recognition were compared. Multivariable regression analysis was performed to assess associations between these parameters and 28-day mortality.ResultsOf 340 patients with septic shock, 92 died. Only the median TWA PP differed between the survivors and non-survivors (39.2 mmHg vs. 43.0 mmHg, p = 0.020), whereas the other indexes did not. When PP was divided into quartiles (< 34, 34 to 40, 40 to 48, and > 48 mmHg), the mortality rate was higher in the highest quartile (41.2%). Multivariable logistic analysis revealed that PP (odds ratio [OR], 1.28; 95% confidence interval [CI], 1.012 to 1.622; p = 0.039) and PP of > 48 mmHg (OR, 2.25; 95% CI, 1.272 to 3.981; p = 0.005) were independently associated with 28-day mortality.ConclusionsPP was significantly associated with 28-day mortality in patients with septic shock and MAP maintained at > 65 mmHg during the first 6 hours. Further studies are warranted to optimize strategies for maintaining PP and MAP at > 65 mmHg during the early resuscitative period.

Sampling Rate of Polar Organic Chemical Integrative Sampler (POCIS): Influence Factors and Calibration Methods

As a passive sampling device, the polar organic chemical integrative sampler (POCIS) has the characteristics of simple operation, safety, and reliability for assessing the occurrence and risk of persistent and emerging trace organic pollutants. The POCIS, allowing for the determination of time-weighted average (TWA) concentration of polar organic chemicals, exhibits good application prospects in aquatic environments. Before deploying the device in water, the sampling rate (Rs), which is a key parameter for characterizing pollutant enrichment, should be determined and calibrated accurately. However, the Rs values strongly depend on experimental hydrodynamic conditions. This paper provides an overview of the current situation of the POCIS for environmental monitoring of organic pollutants in an aquatic system. The principle and theory of the POCIS are outlined. In particular, the effect factors such as the ambient conditions, pollutant properties, and device features on the Rs are analyzed in detail from aspects of impact dependence and mechanisms. The calibration methods of the Rs under laboratory and in situ conditions are summarized. This review offers supplementary information on comprehensive understanding of mechanism and application of the POCIS. Nevertheless, the Rs were impacted by a combined effect of solute–sorbent–membrane–solution, and the influence extent of each variable was still unclear. On this basis, the ongoing challenges are proposed for the future application of the POCIS in the actual environment, for instance, the need for this device to be improved in terms of quantitative methods for more accurate measurement of the Rs.

Embedded systems and the Internet of Things: Can low-cost gas sensors be used in risk assessment of occupational exposure?

The Internet of Things (IoT) explores new perspectives and possible improvements in risk assessment practices and shows potential to measure long-term and real-time occupational exposure. This may be of value when monitoring gases with short-term maximum levels and for time-weighted average (TWA) concentrations used in standard measuring practices. A functional embedded system was designed using low-cost carbon monoxide (CO) electrochemical sensors and long-range-wide-area-network radio communication technology (LoRaWAN) was used to enable internet connectivity. This system was utilized to monitor gas levels continuously in the working atmosphere of an incineration plant over a 2-month period. The results show that stable and long-term continuous data transfer was enabled by LoRaWAN, which proved useful for detecting rapid changes in gas levels. However, it was observed that raw data from the low-cost sensors did not meet the NIOSH accuracy criteria of 25% of the estimated true concentration based on field data from a co-located gas detector that met the NIOSH accuracy criteria. The new IoT technologies and CO sensor networks shows potential for remote monitoring of exposure in order to: (1) detect rapid changes in CO and other possible hazardous airborne gases; and (2) show the dynamic range of real-time data that may be hazardous for workers in the sampled areas. While the IoT low-cost sensors appear to be useful as a sentinel for monitoring hazardous atmospheres containing CO, the more useful finding may be showing real-time changes and the dynamic range of exposures, thus shedding light on the transient and toxic nature of airborne hazards. More importantly, the low-cost CO sensors are not a clear substitute for the more costly real-time gas detectors that perform within the NIOSH accuracy criteria.

From Smoking-Permitted to Smokefree Prisons: A 3-Year Evaluation of the Changes in Occupational Exposure to Second-Hand Smoke Across a National Prison System.

ObjectivesPrisons in Scotland were one of the few workplaces exempt from the 2006 comprehensive smoking ban in indoor public places, excluding the prison workforce from the health benefits of smokefree workplaces. The November 2018 introduction of comprehensive restrictions on smoking in Scottish prisons aimed to protect prison staff and people in custody from the harmful impacts of second-hand smoke (SHS) exposure. This study presents SHS exposure data gathered after smokefree policy implementation and compares these with data gathered during and before policy development.MethodsDylos DC1700 monitors were used to measure concentrations of fine particulate matter (PM2.5) derived from SHS across Scotland’s 15 prisons. Six days of fixed-site monitoring (09.00 22 May 2019 to 09.00 28 May 2019) were conducted in residential halls in each prison 6 months post-smokefree policy implementation. Prison staff task-based measurements were conducted to assess concentrations of SHS in various locations (e.g. gyms and workshops) and during specific activities (e.g. cell searches, maintenance, and meal service). Utilizing the fixed-site monitoring data, typical daily PM2.5 exposure profiles were constructed for the prison service and time-weighted average (TWA) exposure concentrations were estimated for the typical shift patterns of residential staff pre- and post-smokefree policy implementation. Staff perceptions of changes to SHS exposure were assessed using online surveys.ResultsAnalysis of both fixed-site and mobile task-based PM2.5 measurements showed the smokefree policy implementation was successful in reducing SHS exposures across the Scottish prison estate. Measured PM2.5 in residential halls declined markedly; median fixed-site concentrations reduced by more than 91% compared with measures in 2016 before policy announcement. The changes in the TWA concentrations across shifts (over 90% decrease across all shifts) and task-based measurements (89% average decrease for high-exposure tasks) provide evidence that prison staff exposure to SHS has significantly reduced. Following smokefree policy implementation, the majority of staff reported no longer being exposed to SHS at work.ConclusionsTo our knowledge, this is the first comprehensive international study to objectively measure SHS levels before, during, and after implementation of a smokefree policy across a country’s prison system. The findings confirm that such a policy change can be successfully implemented to eliminate occupational exposures to SHS. The results are highly relevant for other jurisdictions considering changes to prison smoking legislation.

Time-weighted average of fine particulate matter exposure and cause-specific mortality in China: a nationwide analysis

Most previous assessments of the hazardous effects attributable to fine particulate matter (PM2·5) exposure have used ambient PM2·5 as an exposure metric, resulting in substantial bias in effect estimates. We did a study to examine the association between cause-specific mortality and the time-weighted average of PM2·5 exposure after accounting for indoor exposure in 267 cities in China. We did a nationwide study, using Laser Egg air quality monitors in 36 cities to obtain data for indoor PM2·5 concentrations from 18 484 anonymised households between Nov 1, 2015 and July 2, 2018. We developed and validated a nationwide indoor PM2·5 prediction model for a further 302 cities by retrieving raw records of hourly concentrations from residents' air sensors; the model was used to predict indoor PM2·5 during 2013 to 2018. Daily ambient PM2·5 concentration data were estimated by averaging hourly ambient PM2·5 concentrations obtained from China's National Urban Air Quality Real-time Publishing Platform. Daily numbers of deaths from all non-accidental causes were obtained from 324 cities from the Disease Surveillance Point System of China between Jan 1, 2013, to Dec 31, 2017, and calculated for 267 cities that had an average daily mortality above three, and data for PM2·5 concentrations and meteorological information for at least 1 year between 2013 and 2017. We used distributed lag non-linear models to estimate city-specific associations between cause-specific mortality and reconstructed PM2·5 exposure by considering indoor PM2·5 exposure. We combined the city-specific effect estimates at the national level using a random effects meta-analysis. 13 972 records of daily indoor PM2·5 concentrations for 36 cities, extracted from 47 459 183 raw records from the sensors were included for modelling indoor PM2·5 levels. The nationwide indoor PM2·5 concentration was 40 μg/m3 (SD 21) between 2013 and 2017, which was approximately 20% lower than the ambient PM2·5 concentration of 50 μg/m3 (42). An increase of 10 μg/m3 in time-averaged PM2·5 exposure concentrations was associated with increased daily mortality estimates of 0·44% (95% CI 0·33-0·54) for total non-accidental causes, 0·50% (0·37-0·63) for cardiovascular diseases, 0·46% (0·28-0·63) for coronary heart disease, 0·49% (0·32-0·66) for stroke, 0·59% (0·39-0·79) for respiratory diseases, and 0·69% (0·45-0·92) for chronic obstructive pulmonary disease, respectively. Compared with previous estimations based on ambient PM2·5, our estimates approximately doubled the size of the effects related to PM2·5. This nationwide study revealed a higher mortality risk attributed to time-averaged indoor and ambient PM2·5 exposure compared with the risk associated with ambient PM2·5 exposure alone, which indicates that caution should be exercised when using ambient PM2·5 as a surrogate for PM2·5 exposure. National Natural Science Foundation of China (Youth Program) and the Fundamental Research Project of Beihang University.

Cascading effects caused by fenoxycarb in freshwater systems dominated by Daphnia carinata and Dolerocypris sinensis

To evaluate the aquatic hazards of the insect juvenile hormone analogue fenoxycarb, a single application (0, 48.8, 156.3, 500, 1600, and 5120 μg/L) of it was done in indoor freshwater systems dominated by Daphnia carinata (daphnid) and Dolerocypris sinensis (ostracoda). The responses of zooplankton (counted by abundance and the activity and immuno-reactive content of free N-Acetyl-β-D-glucosaminidase (NAGase)), phytoplankton (counted by chlorophyll and phycocyanin), planktonic bacteria and fungi, and some water quality parameters were investigated in a period of 35 d. Results of the study showed that the ostracoda was more sensitive than daphnid, with time-weighted average (TWA)-based no observed effect concentrations (NOECs) to be 8.45 and 12.66 μg/L in systems without humic acid addition (HA−) and to be 6.37 and 9.54 μg/L in systems with humic acid addition (HA+). The duration of treatment-related effects in the ostracoda population was longer than the daphnid population (21 vs. 14 days). Besides, the data analysis indicated that the toxicity of fenoxycarb was significantly enhanced in the HA+ systems. Owing to the reduced grazing pressure, the concentrations of chlorophyll and phycocyanin increased in the two highest treatments. The increase in photosynthesis along with a reduced animal excretion led to an increase in pH and a decrease in nutrient contents. These changes seemed to have an effect on the microbial communities. For example, the abundances of some opportunistic pathogens of aquatic animals (e.g. Aeromonas and Cladosporium) and organic-pollutant-degrading microorganisms (e.g. Ancylobacter and Azospirillum) increased significantly in microbial communities, but the abundances of Pedobacter, Candidatus Planktoluna, and Rhodobacter (photosynthetic bacteria) markedly decreased. This study provides useful information to understand the ecotoxicological impacts of fenoxycarb at the population and community levels while integrating the effects of HA on toxicity.

Quantitative evaluation of polyethersulfone and polytetrafluoroethylene membrane sorption in a polar organic chemical integrative sampler (POCIS)

The lag effect in the polar organic chemical integrative sampler (POCIS) equipped with a polyethersulfone (PES) membrane (POCIS-PES) is a potential limitation for its application in water environments. In this study, a POCIS with a poly(tetrafluoroethylene) (PTFE) membrane (POCIS-PTFE) was investigated for circumventing membrane sorption in order to provide more reliable concentration measurements of organic contaminants. Sampler characteristics such as sampling rates (RS) and sampler-water partition coefficients (KSW) were similar for POCIS-PES and POCIS-PTFE, indicating that partitioning into Oasis HLB as the receiving phase dominates the overall partitioning from the aqueous phase to the POCIS. Membrane sorption was quantified in both laboratory and field experiments. Although POCIS-PTFE showed minor membrane sorption, the PTFE membranes were not robust enough to prevent changes in the sorption of the pollutants to the inner Oasis HLB sorbent due to biofouling. This was reflected in significant ionization effects in the electrospray ionization (ESI) source during the LC-MS/MS analysis. Despite clear differences in the ionization effects, the two POCISs types provided similar time-weighted average (CTWA) concentrations after a two-week passive sampling campaign in surface water and the outflow of a wastewater treatment plant. This study contributes to a more detailed understanding of POCIS application by providing a quantitative evaluation of membrane sorption and its associated effects in the laboratory and field.

Relative Hypotension and Adverse Kidney-related Outcomes among Critically Ill Patients with Shock. A Multicenter, Prospective Cohort Study.

Rationale: There are no prospective observational studies exploring the relationship between relative hypotension and adverse kidney-related outcomes among critically ill patients with shock.Objectives: To investigate the magnitude of relative hypotension during vasopressor support among critically ill patients with shock and to determine whether such relative hypotension is associated with new significant acute kidney injury (AKI) or major adverse kidney events (MAKE) within 14 days of vasopressor initiation.Methods: At seven multidisciplinary ICUs, 302 patients, aged ≥40 years and requiring ≥4 hours of vasopressor support for nonhemorrhagic shock, were prospectively enrolled. We assessed the time-weighted average of the mean perfusion pressure (MPP) deficit (i.e., the percentage difference between patients' preillness basal MPP and achieved MPP) during vasopressor support and the percentage of time points with an MPP deficit > 20% as key exposure variables. New significant AKI was defined as an AKI-stage increase of two or more (Kidney Disease: Improving Global Outcome creatinine-based criteria).Measurements and Main Results: The median MPP deficit was 19% (interquartile range, 13-25), and 54% (interquartile range, 19-82) of time points were spent with an MPP deficit > 20%. Seventy-three (24%) patients developed new significant AKI; 86 (29%) patients developed MAKE. For every percentage increase in the time-weighted average MPP deficit, multivariable-adjusted odds of developing new significant AKI and MAKE increased by 5.6% (95% confidence interval, 2.2-9.1; P = 0.001) and 5.9% (95% confidence interval, 2.2-9.8; P = 0.002), respectively. Likewise, for every one-unit increase in the percentage of time points with an MPP deficit > 20%, multivariable-adjusted odds of developing new significant AKI and MAKE increased by 1.2% (0.3-2.2; P = 0.008) and 1.4% (0.4-2.4; P = 0.004), respectively.Conclusions: Vasopressor-treated patients with shock are often exposed to a significant degree and duration of relative hypotension, which is associated with new-onset, adverse kidney-related outcomes.Study registered with Australian New Zealand Clinical Trial Registry (ACTRN 12613001368729).

Science, Medicine, and the Anesthesiologist

Science, Medicine, and the Anesthesiologist