Black Carbon Exposure Characteristics in Diesel Engine Vehicle-related Jobs

Real-Time Assessment of Black Carbon Peaks Among Workers Exposed to Diesel Engine Exhaust Emissions.

Characteristics of elementary school children's daily exposure to black carbon (BC) in Korea

Background: Air pollution has many adverse effects on health. In addition to the common sources of urban air pollution, Singapore is periodically affected by smoke haze due to biomass burning in South East Asia. Black carbon (BC) represents one of the most harmful components of air borne Particulate Matter (PM). Aim: of this study was to do continuous ambulatory monitoring of BC exposure levels in Singapore school children and to identify activities that are associated with higher levels of BC exposure. Methods: School children aged 10-12 years, were recruited. The subjects carried a portable aethalometer (microAeth® model AE51) for 24 hours on a typical school day. The aethalometer was set up to record the BC levels at every 5 minute interval at flow rate of 100ml/min. The children filled in a concurrent activity diary. The data was downloaded and analysed. Results: 46 children (mean [SD] age = 11.3 [0.9] years, 22 [47.8%] males) completed the study. The mean (± SE) BC exposure on a typical school day was 3343 (± 174.4) ng/m3/min. Analyses of activity related BC exposure levels showed a significantly higher BC exposure during commuting to and from school (median [IQR] BC = 5082 [3026–6304] ng/m3/min), compared to that when at home (median [IQR] BC = 2936 [1745–3911] ng/m3/min, p<0.001), school (median [IQR] BC = 3336 [2360–4569] ng/m3/min, p<0.05) and during other activities (median [IQR] BC = 2757 [2084–3940] ng/m3/min, p<0.001). Conclusions: Our findings suggest that commuting to and from school is associated with higher BC exposure in Singapore school children. Comparative BC exposure levels in other global megacities and the potential adverse respiratory health effects of BC exposure warrant further studies.

An exposure study was conducted as part of a multi-national longitudinal study of lung function in cement production workers. To examine exposure to thoracic aerosol among cement production workers during a 4-year follow-up period. Personal shift measurements of thoracic aerosol were conducted among the cement production workers within seven job types, 22 plants, and eight European countries (including Turkey) in 2007, 2009, and 2011. The thoracic sub-fraction was chosen as the most relevant aerosol fraction related to obstructive dynamic lung function changes. Production factors, job type, and respirator use were recorded by questionnaire. The exposure data were log-transformed before mixed models analysis and results were presented by geometric mean (GMadj) exposure levels adjusted for plant or job type, worker, and season as random effects. A total of 6111 thoracic aerosol samples were collected from 2534 workers. Repeated measurements were obtained from 1690 of these workers. The GMadj thoracic aerosol levels varied between job types from 0.20 to 1.2mg m(-3). The highest exposure levels were observed for production, cleaning, and maintenance workers (0.79-1.2mg m(-3)) and could reach levels where the risk of lung function loss may be increased. The lowest levels were found for administrative personnel (0.20mg m(-3)) serving tasks in the production areas. Office work was not monitored. GMadj exposure levels between plants ranged from 0.19 to 2.0mg m(-3). The time of year/season contributed significantly to the total variance, but not year of sampling. Production characteristics explained 63% of the variance explained by plant. Workers in plants with the highest number of employees (212-483 per plant) were exposed at a level more than twice as high as those in plants with fewer employees. Other production factors such as cement production, bag filling, and tidiness were significant, but explained less of the exposure variability. These determinants factors can be useful in qualitative exposure assessment and exposure prevention in the cement production industry. Respirator use was minor at exposure levels <0.5mg m(-3) but more common at higher levels. Production, cleaning, and maintenance work were the job types with highest exposure to thoracic aerosol in cement production plants. However, plant had an even larger effect on exposure levels than job type. The number of employees was the most important factor explaining differences between plants. Exposure reached levels where the risk of lung function loss may be increased. No significant differences in exposure between sampling campaigns were observed during the 4-year study period.

A panel study of the acute effects of personal exposure to household air pollution on ambulatory blood pressure in rural Indian women

Household Air Pollution and Children's Blood Pressure

Daily personal exposure to black carbon (BC) in different microenvironments in Hanoi, Vietnam was quantified for the first time. In this study, a portable instrument, microAethe® model AE51, was used to continuously measure BC concentrations in various microenvironments within buildings and transportation modes. Overall average daily personal exposure to BC from those microenvironments was 5.46 µg/h. The highest BC exposure was during commuting 13.48 µg/h and 5.74 µg/h for the motorcyclist and car driver, respectively. In building environments, the highest BC exposure was 3.98 µg/h in a coffee shop with smoking; the lowest BC exposure was 1.54 µg/h in a hospital department; while BC exposure in an office was 1.92 µg/h. The level of BC exposure in an apartment was strongly influenced by building ventilation modes. They were 3.58 µg/h and 2.15 µg/h with doors/windows open and closed, respectively. Our finding confirmed that commuting contributes disproportionately to the total BC exposure due to the high level of BC during traffic/travel. Building ventilation and air conditioning can significantly affect indoor BC levels and should be considered as a measure to reduce BC exposure within buildings in Hanoi.

Globally, about 14% of households have no option but to burn their waste.&amp;#160; Open waste burning is a significant source of black carbon (BC) emissions, yet the exposure of those engaged in this practice has not been interrogated. This study provides the first quantification of personal exposure to BC emissions from open waste burning, revealing critical insights into the potential health risks faced by individuals engaged in this practice. Between November&amp;#8211;December 2023, we conducted a comprehensive field study in Blantyre, Malawi, monitoring BC exposure among 46 volunteers from 23 households over approximately 20 hours on the day waste was burned at their household. Within each household, one individual responsible for burning waste and one non-burner wore MicroAeth MA200 monitors to capture personal exposure data. To summarize exposure, the average BC concentration was calculated for each a) monitoring period, b) for burning times, and c) for non-burning times. The median of these averages was then used to characterize exposure levels. Results showed that waste burners experienced significantly higher BC exposure than non-burners during both burning periods and the overall monitoring period (Wilcoxon signed rank test, p = 0.04). During burning, the median BC exposure for burners was 12.8 &amp;#956;g/m&amp;#179;, over four times higher than the median exposure of non-burners at 2.9 &amp;#956;g/m&amp;#179;. The median BC exposure for burners during the 20-hour monitoring period was 5.1 &amp;#956;g/m&amp;#179;, compared to 3.0 &amp;#956;g/m&amp;#179; for non-burners. Notably, BC exposure levels during non-burning periods were statistically indistinguishable between burners and non-burners (Wilcoxon signed rank test, p = 0.44), with median exposures of 3.6 &amp;#956;g/m&amp;#179; and 2.6 &amp;#956;g/m&amp;#179;, respectively. This study highlights the extreme BC exposure faced by individuals actively burning waste, and underscores the health risks associated with this practice and the need for interventions to mitigate exposure.

Black carbon (BC) is a major component of ambient particulate matter (PM), one of the six Environmental Protection Agency (EPA) Criteria air pollutants. The majority of research on the adverse effects of BC exposure so far has been focused on respiratory and cardiovascular systems in children. Few studies have also explored whether prenatal BC exposure affects the fetus, the placenta and/or the course of pregnancy itself. Thus, this contemporary review seeks to elucidate state-of-the-art research on this understudied topic. Epidemiological studies have shown a correlation between BC and a variety of adverse effects on fetal health, including low birth weight for gestational age and increased risk of preterm birth, as well as cardiometabolic and respiratory system complications following maternal exposure during pregnancy. There is epidemiological evidence suggesting that BC exposure increases the risk of gestational diabetes mellitus, as well as other maternal health issues, such as pregnancy loss, all of which need to be more thoroughly investigated. Adverse placental effects from BC exposure include inflammatory responses, interference with placental iodine uptake, and expression of DNA repair and tumor suppressor genes. Taking into account the differences in BC exposure around the world, as well as interracial disparities and the need to better understand the underlying mechanisms of the health effects associated with prenatal exposure, toxicological research examining the effects of early life exposure to BC is needed.

BACKGROUND AND AIM: Socioeconomic and spatial patterning of personal exposure to air pollution have not been well documented in rural Chinese settings where household solid fuel use is still a major contributor to air pollution. To better understand how air pollution exposures are distributed in settings like these, we investigated personal exposure patterning by social, demographic, and economic factors within- and between- villages in rural Beijing, where a heating energy program is underway to substitute coal with electricity and natural gas. METHODS: We randomly recruited 446 participants in 50 villages from four (of 13) districts in Beijing and measured 24-h personal exposure to fine particulate matter (PM2.5) and black carbon (BC). We administered a comprehensive survey to collect detailed household socio-demographic information, stove and fuel use patterns, and applied principle component analysis (PCA) to construct a composite index (wealth index) to better represent participants’ socioeconomic status (SES). RESULTS:Overall, geometric mean (95% confidence interval) exposures to PM2.5 and BC were 75 (68-82) and 2.6 (2.4-2.8) μg/m3, respectively, ranging at the village-level from 23-387 μg/m3 and from 0.8-11 μg/m3, respectively. Within villages, the highest measured PM2.5 exposures were, on average, 20 times higher than the lowest (range: 3.5-187). Overall, PM2.5 and BC exposures did not vary systematically by SES, although they were slightly concentrated among the poorest 20% of participants, who represented 23% of PM2.5 and 25% of BC exposure by total personal exposure, while the wealthiest 20% represented 17% of PM2.5 and 14% of BC exposure by total personal exposure. CONCLUSIONS:SES did not show a pronounced association with the disparities of exposures to household air pollution in this study. This study addresses critical knowledge gaps on how exposures to household air pollution are distributed by social and demographic factors and aids design of interventions to control household air pollution emissions in settings like rural Beijing. KEYWORDS: Environmental inequality, personal exposure, fine particulate matter (PM2.5), black carbon (BC), residential coal combustion, socioeconomic status

This study aimed to assess the characteristics of exposure to both PM2.5 and black carbon (BC) among subway workers. A total of 61 subway workers, including 26, 23, and 12 subway station managers, maintenance engineers, and train drivers, respectively, were investigated in 2018. Real-time measurements of airborne PM2.5 and BC were simultaneously conducted around the breathing zones of workers. Maintenance engineers had the highest average levels of exposure to both PM2.5 and BC (PM2.5, 76 µg/m3; BC, 9.3 µg/m3), followed by train drivers (63.2 µg/m3, 5.9 µg/m3) and subway station managers (39.7 µg/m3, 2.2 µg/m3). In terms of the relationship between mass concentrations of PM2.5 and BC, train drivers demonstrated the strongest correlation (R = 0.72), indicating that the proportion of BC contained in PM2.5 is relatively steady. The average proportion of BC in PM2.5 among maintenance engineers (13.0%) was higher than that among train drivers (9.4%) and subway station managers (6.4%). Univariate and mixed effect multiple analyses demonstrated the type of task and worksite to be significant factors affecting exposure levels in maintenance engineers and subway station managers. The use of diesel engine motorcars in tunnel maintenance was found to be a key contributor to PM2.5 and BC exposure levels among subway workers.

Background Personal exposure to traffic related particulate matter is strongly related to the person’s activity pattern and in-traffic exposure. Measuring the personal exposure is invasive for the subjects and expensive in both equipment and support costs. The spatial and temporal variability of Black carbon exposure is much stronger than for PM10 and PM2.5 and shows similar spatial effects as the mobile noise measurements. Aims The aim is to enhance diurnal exposure prediction by using mobile noise measurements and the derived local traffic dynamics as a proxy for in-traffic Black Carbon (BC) exposure. Mobile noise measurements contain interesting data on traffic characteristics and are cheaper to perform and require less support. Methods We first constructed a spatiotemporal model for bicyclists including instantaneous wind speed and traffic dynamics. Next a spatial model, aggregating mobile measurements over a one year period is build to investigate the effects of local traffic dynamics, local features of bicycle facilities and the long term meteorological corrections. Results A strong correlation has been established between the mobile noise exposure and the BC exposure of bicyclists. The bicyclists’ spatiotemporal prediction model reaches an average trip exposure correlation of 0.86. In the long term spatial model the meteorological effects fade out when sufficient measurements are available. The mobile noise measurement increases the quality of the prediction of the spatial variation of BC exposure significantly compared to models that use only traffic data as primary input. Conclusions Mobile noise measurements can be used as a proxy for BC to map cities at an unprecedented spatial resolution, including the actual local traffic dynamics effects. After correcting the BC exposure for background concentrations, the mobile noise measurements are a valid proxy for personal BC exposure.

Personal black carbon exposure and its determinants among elderly adults in urban China

Background: A growing body of evidence shows that cardiovascular disease in adulthood, in particular that of the microcirculation, could find its roots during prenatal development. In this study we investigated the association between pre- and postnatal black carbon and particulate air pollution exposure on heat-induced skin hyperemia as a dynamic marker of the microvasculature. Methods: In 139 children between the age of 4 to 6 who are followed longitudinally within the ENVIRONAGE birth cohort, we measured skin perfusion by Laser Doppler probes using the Periflux6000. Residential black carbon (BC) and particulate (PM10 and PM2.5) air pollution levels were modelled for each participant’s home address using a high-resolution spatiotemporal model. We assessed the association between skin hyperemia and pre- and postnatal air pollution using linear regression models while adjusting for relevant covariates. Results: Prenatal residential BC exposure averaged (IQR) 1.38 (1.05 - 1.62) µg/m³, PM10 18.72 (14.44 - 22.78) µg/m³ and PM2.5 13.43 (9.19 - 17.26) µg/m³. An IQR increment in BC exposure during the third trimester of pregnancy was associated with a 13.8 % (95% CI: -22.7 to -3.9; p = 0.008) lower skin hyperemia. Similar effect estimates were retrieved for PM10 and PM2.5 (respectively 11.7 % (95% CI: -20.6 to -1.8; p = 0.022) and 14.2 % (95% CI: -25.1 to -1.8; p = 0.027) lower skin hyperemia). Postnatal exposure to BC, PM10 or PM2.5 was not associated with skin hyperemia at the age 4 to 6 and did not alter the previous reported prenatal associations. Conclusion: These findings support that BC and particulate air pollution exposure even at low concentrations during prenatal life can have long-lasting consequences on the microvasculature. This proposes a role of prenatal air pollution exposures in the microvascular origin of cardiovascular disease development later in life.

Application 30 - Ceramic Filter for Trapping Diesel Particles