Respiratory Deposition Dose Research Articles

Respiratory Deposition Dose of PM2.5 and PM10 Before, During and After COVID-19 Lockdown Phases in Megacity-Delhi, India

Considerable changes in particulate matter (PM) during COVID-19 lockdown in major cities around the World demand changes in exposure assessment studies of PM. The present study shows variations in respiratory deposition dose (RDD) of both fine (PM2.5) and coarse (PM10) particles before, during and after Covid-19 lockdown phases at three sites (with different pollution signatures) in Delhi—Alipur, Okhla and Pusa Road. Exposure assessment study showed mean PM2.5 RDD (± S.D.) (µg/min) for walk and sit mode during before lockdown (BL) as 2.41(± 1.20) and 0.84(± 0.42) for Alipur, 2.71(± 1.60) and 0.94(± 0.56) for Okhla, and 2.54(± 1.28) and 0.88(± 0.44) for Pusa road, which decreased drastically during Lockdown 1(L1) as 0.85(± 0.35) and 0.30(± 0.12) for Alipur, 0.83(± 0.33) and 0.29(± 0.11) for Okhla, and 0.68(± 0.28) and 0.23(± 0.10) for Pusa road, respectively. Mean PM10 RDD (± S.D.) (µg/min) for walk and sit mode during before lockdown (BL) as 3.90 (± 1.73) and 1.36 (± 0.60) for Alipur, 4.74 (± 2.04) and 1.65 (± 0.71) for Okhla, and 4.25 (± 1.69) and 1.48 (± 0.59) for Pusa Road, respectively which decreased drastically during Lockdown 1(L1) as 2.19 (± 0.95) and 0.76 (± 0.33) for Alipur, 1.73 (± 0.67) and 0.60 (± 0.23) for Okhla and, 1.45 (± 0.50) and 0.50 (± 0.17) for Pusa Road, respectively. Significant decrease in RDD concentrations (Both PM2.5 and PM10) than that of BL phase have been found during Lockdown 1(L1) phase and other successive lockdown and unlock phases—Lockdown 2(L2), Lockdown 3(L3), Lockdown 4(L4) and Unlock1 (UL1) phases. Changes in RDD values during lockdown phases were affected by lesser traffic emission, minimized industrial activities, biomass burning activities, precipitation activities, etc. Seasonal variations of RDD showed Delhites are found exposed to more fine and coarse particles’ RDD (walk and sit modes) before and after lockdown, i.e. during normal days than during lockdown phases showing potential health effects. People in sit condition found less exposed to fine and coarse RDD comparison to those in walk condition both during normal and lockdown days.

Three-dimensional diffusion patterns of traffic-related air pollutants on the roadside based on unmanned aerial vehicles monitoring

There are many studies on the horizontal diffusion of traffic emissions on the roadside, but not enough on the three-dimensional diffusion patterns mainly because of the lack of three-dimensional monitoring data. However, understanding three-dimensional diffusion patterns is critical because it is closely related to the health exposure of residents in roadside multi-story dwellings. Based on the unmanned aerial vehicle platform, this study carried out vertical and horizontal monitoring experiments on traffic-related air pollutants at urban intersections and suburban highways of Cangzhou city, and found that the vertical and horizontal impact ranges of black carbon and coarse particulate matter under free diffusion conditions were respectively in the vicinity of 100 m and 50 m. Compared with particles, the vertical and horizontal impact influence ranges of gaseous pollutant CO2 are higher than black carbon and coarse particulate matters and reached 400 m and 300 m. Meanwhile, the vertical and horizontal impact influence ranges of O3 and fine particulate matters which represented secondary air pollutants were approximately 300 m. The effect of wind can also significantly influence the impact range of various pollutants, and may lead to the transport of pollutants from the suburbs to the urban area. Furthermore, this study found that traffic participants or roadside residents in urban areas are more exposed to black carbon inhalation than those in suburban areas based on the respiratory deposition dose investigation.

Study on effect of tire burning on particulate matter concentration and respiratory deposition doses to the workers and inhabitants during road pavement activity

Study on effect of tire burning on particulate matter concentration and respiratory deposition doses to the workers and inhabitants during road pavement activity

Comparison of exposure to traffic-related pollutants on different commuting routes to a primary school in Jinan, China.

Traffic-related pollutants seriously affect human health, and the commute time to and from school is the time when students are exposed greatest to traffic pollution sources. Field measurements were conducted with hand-held instruments while walking along two selected commuting routes in winter and spring. The measured data were then compared with background monitoring data, and the respiratory deposition dose (RDD) was calculated to assess the exposure risk. Particulate matter intake from 2018 to 2020 was calculated. In winter, the average concentrations of PM2.5 and PM10 were higher in the afternoon than in the morning. The highest concentration was 2.94 times greater than the background value. The low-concentration distribution area of the low-traffic route that is off the main road (route B) was more significant than that of the high-traffic route that is near the main road (route A). Moreover, the RDD of route B was consistently lower than that of route A, while the average annual amount of PM2.5 inhalation on route B in 3 years was 16.3% lower than that on route A. Overall, route B is more suitable than route A for students to commute on foot. Based on the findings, a walking route located within a community is a good choice.Supplementary InformationThe online version contains supplementary material available at 10.1007/s11356-021-18362-w.

Exposure assessment of PM2.5 in temple premises and crematoriums in Kanpur, India.

Regular use of incense and earthen lamps in temples leads to the release of particulate matter (PM), airborne flecks, and gaseous pollutants. Similarly, the cremation of dead bodies using timber and other accessories such as incense, organic chemicals containing carbon, and clothes generates air pollutants. It is currently unclear how much emissions and exposure these activities may lead. This work attempts to fill this gap in our understanding by assessing the associated emissions of PM2.5 and the corresponding exposure. Ten temples and two cremation grounds were considered for the sampling of PM2.5. The average PM2.5 concentration at the ten temples and the two crematoriums was found to be 658.30 ± 112.63µg/m3 and 1043.50 ± 191.63µg/m3, respectively. The range of real-time PM2.5 data obtained from the nearest twelve stations located in the vicinity was 113-191µg/m3. The exposure assessment in terms of deposition dose was carried out using the ICRP model. The maximum and minimum total respiratory deposition dose rate for PM2.5 for temples was 175.75µg/min and 101.15µg/min, respectively. For crematoriums, the maximum and minimum value of same was 252.3µg/min and 194.31µg/min, respectively, for an exposure period of 10min.

Air Quality outside Schools in Newcastle upon Tyne, UK: An Investigation into NO2 and PM Concentrations and PM Respiratory Deposition

Air pollution is the principal environmental threat to public health in the UK. Ever-increasing evidence links ambient air pollutants, preventable diseases, and health inequalities. Children are particularly vulnerable to harmful effects due to their short height, developing lungs, and higher rate of respiration. Using data from air quality monitors around schools, we investigated 2018–2019 ambient NO2, PM10, PM2.5, and PM1 concentrations at 12 schools in Newcastle upon Tyne, UK. We compared findings with EU/UK air quality regulations and guidelines, identified patterns, and calculated PM respiratory deposition doses (RDDs). The range of annual average (AA) concentrations across the schools for the two-year period was 23.7–39.2 µg/m3 for NO2, 7.4–22.2 µg/m3 for PM10, 3.5–11.6 µg/m3 for PM2.5, and 1.7–9.0 µg/m3 for PM1. The highest PM RDD children were exposed to at school was 30 µg/h. One school’s AA NO2, two schools’ hourly PM2.5 averages, and one school’s 24-h PM10 averages exceeded EU/UK regulations. All schools exceeded WHO2005 24-h PM10 and PM2.5 guidelines in 2018, less in 2019. All 12 schools would have exceeded WHO2021 NO2 AA guidelines (10 µg/m3), 2 the WHO2021 PM10 AA (15 µg/m3), and 10 the WHO2021 PM2.5 AA (5 µg/m3). Evidence-based policy is required to improve school ambient air quality and reduce children’s exposure.

Seasonal Variability of Resuspension

Particulate air pollution in cities is caused by a variety of sources. One of the less-studied contributors is wind-induced particle resuspension. As the wind speed increases, particles are removed from surfaces. These particles cause an increase in the total concentration in the air. It is known that particles of 10-2.5 μm in size can be resuspended (PM10-2,5). Modern emission monitoring in cities also allows the monitoring of fine particles of 10, 2.5 and 1 μm in size. The size fractions can then be sorted into PM10-2,5, PM2,5-1 and PM1. When breathed in, particles of different sizes cause various serious health risks. This paper focuses on the identification of the resuspension process of different particle size fractions by a data processing method. Data measured by automatic emission monitoring are used. It is confirmed that the concentration increase can be dominated by the fraction PM10-2,5. However, a concentration increase of fractions PM2,5-1 and PM1 is also evident with increasing wind speed. Although the increase in the PM1 fraction is smaller than PM10-2,5, it is more severe due to the respiratory deposition dose. The resuspension of particles of different fractions has different behaviours during the year. PM10-2,5 particles are dominantly resuspended in the summer months. In winter, on the other hand, the proportion of PM2.5-1 and PM1 particles increases, which may be related to the heating season

Characterizing the Particle Variations and Human Exposure in Port and Urban Areas

In port areas, traffic is characterized by container trucks which run on diesel, while in urban areas it is characterized by private cars which run on petrol. The different fuels as pollution sources cause distinct particle pollution. This study offers an in-depth investigation of particle pollution and corresponding short-term exposures in port and urban areas. Field measurements were carried out to collect the data including particulate matter and traffic volume. Based on the data, firstly, the Pearson correlation analysis was performed to analyze the relationships between traffic volume and particles. Secondly, the Anderson–Darling test was adopted to identify the “best-fit” distributions on particles. Thirdly, comparisons of particle pollution levels in port and urban areas were analyzed. Finally, the pedestrian respiratory deposition doses of particles were estimated. The results indicate the importance and urgency of reducing air pollution, especially for port cities, and provide policymakers with a foundation for possible measures in the port city.

Spatial distribution of the size-fractional PNC and Pedestrian exposure to PM at an urban signalized intersection

To evaluate the respiratory health risk of pedestrians at signalized intersections, it is crucial to accurately investigate their spatial distribution of particulate matter (PM) in the air and the respiratory exposure dose to the public. The particle number concentrations (PNCs) of different sizes (10–2500 nm) along the horizontal and vertical vibrations of the intersection were measured in Xi'an, China, and the respiratory deposition dose (RDD) rate of pedestrians was calculated to estimate the pedestrian exposure level. The mean PNC at the intersection's entrance (1.59 × 104 # cm−3) was larger than at its exit (1.34 × 104 # cm−3) irrespective of the particle mode. At the exit, moreover, the PNC values decreased exponentially with increasing distance from the parking baseline of the intersection, while no such damping characterized the entrance to it. Concerning the vertical vibration of the intersection, both nucleation and Aitken modes of PNC peaked at a 0.4-m height and the maximum PNC in the accumulation mode and coarse mode appeared at a height of 3.4–4.5 m. Average RDD rate at the signalized intersection's entrance and exit was respectively 8.103 μg h−1 and 7.523 μg h−1. For this same intersection, the highest PM exposure dose was 8.444 μg h−1 for the elderly, followed by 8.061 μg h−1 for adults, and 3.221 μg h−1 for children.

Characterizing spatiotemporal distributions of black carbon and PM2.5 at a toll station: Observations on manual and electronic toll collection lanes

Toll stations are traffic-related pollution hotspots, but the contribution of various factors to pollutant distributions has not been clearly recognized. This study conducted a field investigation of the spatiotemporal variations of pollutants on different lanes at a toll station in Shanghai, China. Quantitative analysis showed that the concentrations of black carbon (BC) and fine particles (PM2.5) on the manual toll collection (MTC) lane were higher than those on the electronic toll collection (ETC) lane, and higher concentrations were identified on weekdays. Furthermore, the study introduced interaction terms between lane type and traffic conditions while constructing generalized additive models (GAMs) to reveal the internal relationship between concentrations and explanatory variables. The results of GAM analysis showed that the coupling effect of traffic volume and lane type was the most important force driving variations in BC, while background concentration was the dominant factor of PM2.5 variations. The Extreme Gradient Boosting (XGBoost) models were developed to separately evaluate the influence of lane type and traffic volume on BC and PM2.5, indicating that lane type contributed 29.4% and 36.5% of BC and PM2.5 variations respectively. Additionally, simulation demonstrated that in contrast to MTC, ETC can reduce BC pollution by 25.2% under the same traffic conditions. Finally, the respiratory deposition dose was used to compare the negative consequences of exposure between the ETC and MTC lane. This study revealed the general variation trends of pollutants and corresponding influencing factors at a toll station, and could provide implications for mitigating traffic-related pollution.

Study on respiratory deposition doses of typical Indian opencast coal mineworkers using occupational particulate matter levels

The opencast coal mineworkers experience site-specific microenvironments (MEs) during coal production due to different benches. This study investigates the particulate matter (PM0.5, PM0.5-1, PM1-2.5, and PM2.5-10) exposure in MEs of opencast coal mines near Dhanbad, India. The present study estimates the respiratory deposition doses (RDD) to mineworkers exposed under standard working scenarios at the worksite during day time shift (DTS). The coarser mode particle mass concentration (PMC) and particle number concentration (PNC) are 1.4 to 10.6 and 2 to 7.5 times higher within mines at active mining locations, whereas accumulation mode PMC and PNC is 1.1 to 1.5 and 1.1 to 1.9 times higher outside the mines. The opencast mining-associated activities like the excavation of coal and overburden contribute more to the coarser fraction of particles. However, accumulation mode PMC and PNC dominates at locations with no such mining activities except dumper operations. The average RDD of PMC and PNC during DTS to mineworkers varies from 320.97 μg DTS-1 and 3.69×108 # DTS-1 and 3835.71 μg DTS-1 and 8.79×108 # DTS-1 respectively. The occupational RDD results reveal that onsite maintenance workers (OM) category of mineworkers are more vulnerable to accumulation mode PMC followed by blasting associated mineworkers (B), onsite executives (EM), maintenance workers (workshop) (MW), monitoring workers (M), HEMMs operators (O), workers at gathering point (G), and official executives (EO). Whereas OM category of workers is more vulnerable to coarser mode PMC followed by B, M, EM, O, MW, G, and EO category of mineworkers.

Evaluation of respiratory deposition doses in the presence of green infrastructure

Green infrastructure (GI) is effective in reducing PM concentrations in near-road environments, but how such reductions in concentration compared with relative respiratory deposition doses (RDDs) is rarely discussed. We quantified variations in RDD in the presence of three GI types (trees, hedges and tree-hedge combinations), and compared them with PM reduced by the GI under different wind directions and seasons through the assessment of data collected during multiple field campaigns. We also studied three scenarios (sitting, walking, running) to investigate RDD in adults and children during different possible activities in the presence of GI at public parks or gardens or in front of houses. Finally, we illustrated particle mass distribution before and after different GI configurations to explore the reasons for variations in RDD. Changes in RDD displayed a trend of %ΔRDDPM10 > %ΔRDDPM2.5 = %ΔRDDPM1, compared to the changes in PM concentrations of %ΔPM1 > %ΔPM10 > %ΔPM2.5. A maximum reduction (25%) in RDD was observed for PM10 in the presence of the tree-hedge combination, and this combination emerged as the most effective GI type in lowering the RDD. The changes in ratios of mass median diameter and deposition fraction of roughly ±0.2 before and after the GI led to differences between %∆PM and %∆RDD. Cross-winds (perpendicular to road direction) led to greater variations between %∆PM and %∆RDD, whereas parallel winds (along the road) led to similar variations in %∆RDD and %∆PM. Particle mass distributions revealed the absence of a peak around particle diameter 2.5 μm in the presence of GI. The highest difference in RDD behind GI was observed in the presence of a hedge-tree combination during different physical activities.

Analysis of various transport modes to evaluate personal exposure to PM2.5 pollution in Delhi

Access to detailed comparisons of the air quality variations encountered when commuting through a city offers the urban traveller more informed choice on how to minimise personal exposure to inhalable pollutants. In this study we report on an experiment designed to compare atmospheric contaminants, in this case, PM2.5 inhaled during rickshaw, bus, metro, non-air-conditioned car, air-conditioned (AC) car and walking journeys through the city of Delhi, India. The data collection was carried out using a portable TSI SidePak Aerosol Monitor AM520, during February 2018. The results demonstrate that rickshaws (266 ± 159 μg/m3) and walking (259 ± 102 μg/m3) modes were exposed to significantly higher mean PM2.5 levels, whereas AC cars (89 ± 30 μg/m3) and the metro (72 ± 11 μg/m3) had the lowest overall exposure rates. Buses (113 ± 14 μg/m3) and non-AC cars (149 ± 13 μg/m3) had average levels of exposure, but open windows and local factors caused surges in PM2.5 for both transport modes. Closed air-conditioned transport modes were shown to be the best modes for avoiding high concentrations of PM2.5, however other factors (e.g. time of the day, window open or closed in the vehicles) affected exposure levels significantly. Overall, the highest total respiratory deposition doses (RDDs) values were estimated as 84.7 ± 33.4 μg/km, 15.8 ± 9.5 μg/km and 9.7 ± 0.9 μg/km for walking, rickshaw and non-AC car transported mode of journey, respectively. Unless strong pollution control measures are taken, the high exposure to PM2.5 levels will continue causing serious short-term and long-term health concerns for the Delhi residents. Implementing integrated and intelligent transport systems and educating commuters on ways to reduce exposure levels and impacts on commuter's health are required.

Exposure and Respiratory Tract Deposition Dose of Equivalent Black Carbon in High Altitudes

The traffic microenvironment accounts for a significant fraction of the total daily dose of inhaled air pollutants. The adverse effects of air pollution may be intensified in high altitudes (HA) due to increased minute ventilation (MV), which may result in higher deposition doses compared to that at sea level. Despite this, air quality studies in regions with combined high pollution levels and enhanced inhalation are limited. The main goals of this study are to investigate how the choice of travel mode (walking, microbus, and cable car ride) determines (i) the personal exposure to equivalent black carbon (eBC) and (ii) the corresponding potential respiratory deposited dose (RDD) in HA. For this investigation, we chose La Paz and El Alto in Bolivia as HA representative cities. The highest eBC exposure occurred in microbus commutes (13 μg m−3), while the highest RDD per trip was recorded while walking (6.3 μg) due to increased MV. On the other hand, the lowest eBC exposure and RDD were observed in cable car commute. Compared with similar studies done at sea level, our results revealed that a HA city should reduce exposure by 1.4 to 1.8-fold to achieve similar RDD at sea level, implying that HA cities require doubly aggressive and stringent road emission policies compared to those at sea level.

Evaluation of the effectiveness of a portable air cleaner in mitigating indoor human exposure to cooking-derived airborne particles

Gas cooking is an important source of airborne particulate matter (PM) indoors. Exposure to cooking-derived PM can lead to adverse human health impacts on non-smokers, especially in poorly-ventilated residential homes. Most of the previous studies on gas cooking emissions mainly focused on fine particles (PM2.5) with little information on their size-fractionation. Moreover, studies dealing with mitigation of indoor human exposure to cooking-derived PM are currently sparse. Therefore, a systematic study was conducted to investigate the characteristics of PM2.5 and size-fractionated PM derived from five commonly used cooking methods, namely, steaming, boiling, stir-frying, pan-frying and deep-frying in a poorly-ventilated domestic kitchen under controlled experimental conditions. Additionally, an indoor portable air cleaner was employed as a mitigation device to capture cooking-derived PM and improve indoor air quality (IAQ). Results revealed that the oil-based deep-frying cooking released the highest airborne particles which were about 170 folds higher compared to the baseline levels for PM2.5 mass concentrations. The use of the air cleaner showed a statistically significant (p < 0.05) reduction in the indoor PM2.5 levels. Moreover, PM<0.25 (particles with diameter ≤ 250 nm) showed a very high mass concentration (378.2 μg/m3) during deep-frying, raising human health concern. A substantial reduction (~60–85%) in PM<0.25 mass concentrations and their total respiratory deposition doses (RDD) in the human respiratory tract was observed while using the air cleaner during the five cooking methods. Furthermore, morphological characteristics and the relative abundance of trace elements in cooking-derived PM were also investigated. This study provides useful insights into the assessment and mitigation of indoor human exposure to cooking-derived PM.

Chemical Composition of Quasi-ultrafine Particles and their Sources in Elderly Residences of São Paulo Megacity

Atmospheric quasi-ultrafine particles (qUFP; PM<0.25) can cause harmful effects to human health, mainly to elderly people. Although not always considered, these effects can be mostly due to its chemical composition. The scope of this work is (i) to quantify the abundance of ions and trace elements in qUFP in elderly residences, (ii) to identify the sources of these qUFP and (iii) to estimate the respiratory deposition doses (RDD) of qUFP and black carbon (rBC), which is an important component of qUFP, to various parts of the respiratory tract. In order to evaluate the qUFP chemical composition in elderly residences in the Metropolitan Area of Sao Paulo (MASP), we collected qUFP by using a Personal Cascade Impactor Sampler (PCIS). We analysed ions by chromatography and trace elements by Energy Dispersive X-Ray Fluorescence. We identified the sources of qUFP by applying Positive Matrix Factorization. We calculated the RDD through an equation, which use the tidal volume of lung, the typical breath frequency, the deposition fraction and the mass concentration of different size fractions of a PM. We collected 60 samples from 59 residences between May 2014 and July 2015. The major of ions concentrations in qUFP were found to be SO42- and NH4+, and the major trace elements were Si and Fe. Some residences have a high concentration of the toxic heavy metals Cu, Ni, Pb and Cr. We found six dominant sources of the indoor qUFP: vehicular emission (57%), secondary inorganic aerosol (21%), soil and construction (7%), wall painting (7%), cooking (5%) and industry (3%). The maximum RDD of qUFP and rBC are in the tracheobronchial part. Our results show that vehicular emissions dominate the indoor qUFP concentrations and uptake in elderly residences in the MASP.

On-site and off-site material preparation pavement approaches on particle emission and associated health impacts on workers

The resurfacing of urban road networks is a prevalent practice for extending their life and therefore shares an important contribution to the road transport emissions because of the varying practices of resurfacing with the type of highway owing to its associated cost. This study has been performed to analyze the particulate matter (PM) emission from two different approaches i.e. on-site and off-site material preparation for resurfacing of asphalt road. The distribution of particle number concentration (PNC) in the microenvironments (MEs) around the activity and associated exposure to the workers were also studied. The total PM emission was calculated for both of the approaches by using non-road model and fixed emission factor of AP-42. The highly worker-dependent on-site practice has shown great concern compared to well-equipped off-site, due to high emissions at the pavement site. More contribution of PM at pavement site leads the significant presence of PNC in the working MEs around the activities. At the pavement site of on-site practices, 60% of worker’s were engaged within 25 m of fixed major activity MEs, where activities contribute 59.7% accumulation mode (0.5 µm) and 72.1% coarser mode (1 µm–10 µm) particle in total hourly measured PNC. This emission was 7.2 times to that of off-site practices where 53% of workers were engaged in major source activity (i.e. layering of asphalt). The average respiratory deposition dose in head airways (DFHA), tracheobronchial (DFTB), and alveolar (DFAL) regions were 2.3 × 107, 1.9 × 106 and 1.2 × 107 particles h−1, respectively. The results of the average total dose of deposition of particles were 2.1 times than that of the results of off-site practice. The research findings provide an understanding of particle distribution around pavement activity and health exposure of the worker’s. Particle number concentration at pavement site microenvironment during layering of the road surface by on-site (a) and off-site material preparation pavement approaches. Respiratory deposition doses (RDD) value for worker’s working at on-site (c) and (d) off-site.

A new method to measure real-world respiratory tract deposition of inhaled ambient black carbon

In this study, we present the development of a mobile system to measure real-world total respiratory tract deposition of inhaled ambient black carbon (BC). Such information can be used to supplement the existing knowledge on air pollution-related health effects, especially in the regions where the use of standard methods and intricate instrumentation is limited. The study is divided in two parts. Firstly, we present the design of portable system and methodology to evaluate the exhaled air BC content. We demonstrate that under real-world conditions, the proposed system exhibit negligible particle losses, and can additionally be used to determine the minute ventilation. Secondly, exemplary experimental data from the system is presented. A feasibility study was conducted in the city of La Paz, Bolivia. In a pilot experiment, we found that the cumulative total respiratory tract deposition dose over 1-h commuting trip would result in approximately 2.6 μg of BC. This is up to 5 times lower than the values obtained from conjectural approach (e.g. using physical parameters from previously reported worksheets). Measured total respiratory tract deposited BC fraction varied from 39% to 48% during walking and commuting inside a micro-bus, respectively.To the best of our knowledge, no studies focusing on experimental determination of real-world deposition dose of BC have been performed in developing regions. This can be especially important because the BC mass concentration is significant and determines a large fraction of particle mass concentration. In this work, we propose a potential method, recommendations, as well as the limitations in establishing an easy and relatively cheap way to estimate the respiratory tract deposition of BC.

Respiratory tract deposition of inhaled roadside ultrafine refractory particles in a polluted megacity of South-East Asia

Recent studies demonstrate that Black Carbon (BC) pollution in economically developing megacities remain higher than the values, which the World Health Organization considers to be safe. Despite the scientific evidence of the degrees of BC exposure, there is still a lack of understanding on how the severe levels of BC pollution affect human health in these regions. We consider information on the respiratory tract deposition dose (DD) of BC to be essential in understanding the link between personal exposure to air pollutants and corresponding health effects.In this work, we combine data on fine and ultrafine refractory particle number concentrations (BC proxy), and activity patterns to derive the respiratory tract deposited amounts of BC particles for the population of the highly polluted metropolitan area of Manila, Philippines. We calculated the total DD of refractory particles based on three metrics: refractory particle number, surface area, and mass concentrations. The calculated DD of total refractory particle number in Metro Manila was found to be 1.6 to 17 times higher than average values reported from Europe and the U.S. In the case of Manila, ultrafine particles smaller than 100 nm accounted for more than 90% of the total deposited refractory particle dose in terms of particle number.This work is a first attempt to quantitatively evaluate the DD of refractory particles and raise awareness in assessing pollution-related health effects in developing megacities. We demonstrate that the majority of the population may be highly affected by BC pollution, which is known to have negative health outcomes if no actions are taken to mitigate its emission. For the governments of such metropolitan areas, we suggest to revise currently existing environmental legislation, raise public awareness, and to establish supplementary monitoring of black carbon in parallel to already existing PM10 and PM2.5 measures.

Exposure to traffic-related particulate matter and deposition dose to auto rickshaw driver in Dhanbad, India

Driver's exposure in vehicular systems contributes an important fraction of the daily burden of air pollutants. In this study, we examined the PM concentrations in the various microenvironments (ME's) such as in-vehicle [auto-rickshaws], outdoor and indoor. The drivers were estimated to have respiratory deposition doses (RDDs) of PM fractions (PM10, PM2.5 and PM1) in the different part of the respiratory tract (head airways (HD), tracheobronchial (TB) and alveolar (AL)) in various ME's to auto-rickshaw drivers. The results showed that average PM concentrations were 3.3 times higher inside auto-rickshaws than ambient level. The highest PM fractions concentrations were observed during congestion period (844 μgm−3 for PM10, 458 μgm−3 for PM2.5 and 302 μgm−3 for PM1) of auto-rickshaw riding. The survey reports showed that eighty percent of drivers believed they were more exposed than a non-driver. More than half of auto-rickshaws drives believed, alternative fuel like CNG was a better way to reduce the air pollution. In the health screening, about 23% and 20% of auto-rickshaws drivers complained of the ‘body pain and eye irritation’ and ‘a headache’, respectively. Overall, the total RDDs values were estimated 4.8 (PM10-2.5), 8.8 (PM2.5-1) and 10.1 (PM1) times higher compared to ambient level to auto-rickshaw drivers in an average day. Based on this result, the fine particulate matter showed in a higher risk of auto-rickshaw drivers in Dhanbad city. This study indicated that driver awareness of traffic air pollution was limited. Future studies should focus on reducing exposures and increasing awareness among auto-rickshaw drivers.