Reducing mortality risk by targeting specific air pollution sources: Suva, Fiji

Black carbon and elemental characterization of PM2.5 in dense traffic areas in two cities in Fiji, a Small Island Developing State

PM_2.5 characterizations are essential in understanding its impact on the health of the exposed population. Sampled PM_2.5 by Mani et al. (2020) was characterized to determine atmospheric metal concentration and inhalation health risk in Suva and Lautoka Cities, the only two cities in Fiji and one of the largest in the South Pacific Islands. Twenty-two elements (Al, As, Ba, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Mo, Na, Ni, P, Pb, S, Si, Sr, V, Zn) were analyzed using ICP-OES. Black Carbon (BC) sampling was also done at three different sites in Suva City, namely, Fiji National University Samabula Intersection site, Suva City Bus Station site and the Reservoir Road Community Settlement Site as well as at Lautoka City Bus Station. Mean BC concentrations over the sampling period were found to be 3.9 ± 2.9 (median = 3.3 μg/m³), 2.6 ± 2.7 μg/m³ (median = 1.7 μg/m³), 2.4 ± 2.3 μg/m³ (median = 1.7 μg/m³) and 4.0 ± 4.7 μg/m³ (median = 2.4 μg/m³) respectively. Health risk assessments (Carcinogenic Risk (CR) and Non-Carcinogenic Risk (HQ)) were also done to assess the risk of inhalation exposure in adults and children. The Hazard Index for children in Lautoka (HI = 1.03) was found to slightly exceed the safe level of 1. This study provides the first inventory of atmospheric particulate bound metal concentrations and diurnal BC profiles in Fiji and informs policy makers and scientists for further studies.

Vehicular Traffic in Urban Areas: Health Burden and Influence of Sustainable Urban Planning and Mobility

Vehicular traffic is one of the major sources of air pollution in European cities. This work aims to understand which characteristics of the urban environment could influence mobility-related air pollution, quantify the health impacts of exposure to traffic-derived PM2.5 and NO2 concentrations, and assess the potential health benefits expected from traffic interventions. The health benefits modeled are intended to provide a set of comparable data to support decision-makers and encourage informed decision-making to design healthier cities. Targeting a large geographical coverage, 12 European cities from 9 countries were comparatively assessed in terms of mean daily traffic volume/area, the number of public transport stops/area, and the percentage of green and outdoor leisure areas, among other urban indicators. This was implemented using an open-source data mining tool, which was seen as a useful engine to identify potential strategies to improve air quality. The comparison of urban indicators in the selected cities evidenced two trends: (a) cities with the most heterogeneous distribution of public transport stops, as an indicator of poor accessibility, are also those with the lowest proportion of km dedicated to cycleways and footways, highlighting the need in these cities for more sustainable mobility management; and (b) the percentage of green and outdoor leisure areas may influence the share of journeys by bicycle, pointing out that promoting the perception of green routes is relevant to enhance the potential of active transport modes. Socioeconomic factors can be key determinants of the urban indicators and would need further consideration. For the health impact assessment (HIA), two baseline scenarios were evaluated and compared. One is based on mean annual traffic contributions to PM2.5 concentrations in each target city (ranging between 1.9 and 13 µg/m3), obtained from the literature, and the second is grounded on mean annual NO2 concentrations at all available traffic and urban background stations within each city (17.2–83.5 µg/m3), obtained from the European Environment Agency database. The intervention scenarios modeled were designed based on traffic mitigation strategies in the literature, and set to ranges of 6–50% in traffic-derived PM2.5 concentrations and of 4–12.5% in NO2 concentrations. These scenarios could result in only a 1.7% (0.6–4%) reduction in premature mortality due to exposure to traffic-derived PM2.5, and 1.0% (0.4–2%) due to exposure to NO2, as the mean for all the cities. This suggests that more ambitious pollution abatement strategies should be targeted.

The influences of ambient fine particulate matter constituents on plasma hormones, circulating TMAO levels and blood pressure: A panel study in China

Considerable investigations have been carried out to address the relationship between ambient fine particulate matter (PM_2.5) and blood pressure (BP) in patients with hypertension. However, few studies have explored the influence of PM_2.5 and its constituents on Trimethylamine N-oxide (TMAO), an established risk factor for hypertension and cardiovascular disease (CVD), particularly in severely air-polluted areas. To explore the potential impact of PM_2.5 constituents on BP, plasma hormones, and TMAO, a panel study was conducted to investigate changes in BP, plasma hormones, and TMAO in response to ambient air pollution exposure in stage 1 hypertensive young adults. Linear mixed effect models were used to estimate the cumulative effects of fine particulate matters (PM_2.5) and its constituents on BP, plasma hormones and TMAO. We found that one interquartile range (IQR) (35 μg/m³) increase in 0-1 day moving-average PM_2.5 concentrations was statistically significantly associated with elevated systolic blood pressure (SBP), diastolic blood pressure (DBP), and mean arterial pressure (MAP) with estimated values of 0.13 (95% confidence interval (CI): 0.03 to 0.23) mmHg, 0.18 (95% CI: 0.08 to 0.28) mmHg, and 0.17 (95% CI: 0.09 to 0.26) mmHg, respectively. Hormone disturbance in the renin-angiotensin-aldosterone system was also associated with PM_2.5 exposure. Elevated TMAO levels with an IQR increase for 0-4, 0-5, 0-6 moving-average concentrations of PM_2.5 were found, and the increased values ranged from 26.28 (95% CI: 2.92 to 49.64) to 60.78 (31.95-89.61) ng/ml. More importantly, the PM_2.5-bound metal constituents, such as manganese (Mn), titanium (Ti), and selenium (Se) showed robust associations with elevated BP and plasma TMAO levels. This study demonstrates associations between PM_2.5 metal constituents and increased BP, changes in plasma hormones and TMAO, in stage 1 hypertensive young adults. Source control, aiming to reduce the emission of PM_2.5-bound metals should be implemented to reduce the risk of hypertension and CVD.

International Analysis of Sources and Human Health Risk Associated with Trace Metal Contaminants in Residential Indoor Dust

People spend increasing amounts of time at home, yet the indoor home environment remains understudied in terms of potential exposure to toxic trace metals. We evaluated trace metal (and metalloid) concentrations (As, Cu, Cr, Mn, Ni, Pb, and Zn) and health risks in indoor dust from homes from 35 countries, along with a suite of potentially contributory residential characteristics. The objective was to determine trace metal source inputs and home environment conditions associated with increasing exposure risk across a range of international communities. For all countries, enrichments compared to global crustal values were Zn > Pb > Cu > As > Cr > Ni; with the greatest health risk from Cr, followed by As > Pb > Mn > Cu > Ni > Zn. Three main indoor dust sources were identified, with a Pb-Zn-As factor related to legacy Pb sources, a Zn-Cu factor reflecting building materials, and a Mn factor indicative of natural soil sources. Increasing home age was associated with greater Pb and As concentrations (5.0 and 0.48 mg/kg per year of home age, respectively), as were peeling paint and garden access. Therefore, these factors form important considerations for the development of evidence-based management strategies to reduce potential risks posed by indoor house dust. Recent findings indicate neurocognitive effects from low concentrations of metal exposures; hence, an understanding of the home exposome is vital.

Atmospheric remobilization of natural and anthropogenic contaminants during wildfires

Globally, wildfires are increasing in frequency and severity, exposing populations to toxic trace elements stored within forests. Trace element and Pb isotope compositions in aerosols (n = 87) from four major wildfires near Sydney, Australia (1994-2004) were evaluated (Mood's median test) to determine any significant differences in concentration before, during or after wildfires. The US EPA's positive matrix factorization (PMF) model was used to distinguish a wildfire-related particulate source factor. Atmospheric concentrations of Cd and Mn were approximately 2.5 times higher during fire periods. PMF modelling distinguished a soil factor (Ca, Si, Ti and Zn) and an anthropogenically-sourced factor (Cd, Pb). The Cd, Pb anthropogenic factor was present at twice the concentration during wildfire periods (compared to before or after). Lead isotopic analyses of aerosols revealed that former leaded gasoline depositions were subject to remobilization during post-2000 wildfire periods. Trace element increases during wildfires are unlikely to exceed health-based criteria.

A study of cardiorespiratory related mortality as a result of exposure to black carbon

INTRODUCTION

Air pollution is a global phenomenon which invariably leads to a serious environmental and health related sequalae. "Black carbon" (BC), a subset of fine particulate matter ≤2.5 μm (PM_2.5), is a fossil fuel emission by-product and has more recently been recognized as a major health hazard. The objective of this study is to statistically analyze the BC concentration and its correlation with cardiorespiratory related mortality and to estimate the benefits of BC reduction on the health of the population in the capital city of Tehran.

METHODS

We analyzed the ambient air BC concentration and its correlation with cardiorespiratory related mortality and conducted health impact assessment of BC in Tehran (Jan 2018-Jan 2019). The data pertaining to BC concentration was obtained from Tehran's four major pollution monitoring stations. The mortality data was obtained from Tehran's cemetery registry. We calculated and analyzed BC concentration statistics including the mean, standard deviation, coefficient of variation, skewness, and kurtosis. We then assessed the cross-correlation and temporal relationship (0-7 days) between the daily mean concentration of BC for the entire city and cardiorespiratory related mortality. The BenMAP software was utilized to estimate the potential reduction in cardiorespiratory related mortality rates if BC concentration is reduced. Three hypothetical scenarios were employed in the analysis, utilizing the BenMAP software: (I) BC concentration was completely removed from the ambient air; (II) BC concentration was eliminated, and the remaining (non-BC portion of) PM_2.5 concentration was reverted to the United States Environmental Protection Agency (EPA)'s standard level (i.e., 35 μg/m³); and (III) The BC emission during the night (22:00 h-6:00 h, when heavy-duty vehicles (HDVs) are allowed to commute in the city) was distributed throughout the whole day. Since the planetary boundary layer during daytime is much higher than that of nighttime, with the same rate of emission, lower concentrations are spread during the whole day.

RESULTS

The trend of BC concentration variation revealed a persistently higher emission of BC during the nighttime, which is consistent with the large-scale operation of HDVs during these hours in the city of Tehran. We observed a direct correlation between BC concentration and cardiorespiratory related mortality. Analysis also showed a 1.4-day lag period from the time of exposure to BC polluted air and respiratory related deaths, and 2 days for cardiovascular related deaths. As a result, the reduction in BC has significant beneficial effects in reducing potentially preventable cardiorespiratory related mortality. The aforementioned three scenarios for age groups of 30 and above yielded the following results: (I) 11,369 (126 per 100,000 population), (II) 15,386 (171 per 100,000 population), and (III) 2552 (28 per 100,000 population) potentially preventable all-cause (including cardiorespiratory) related deaths annually.

CONCLUSIONS

The BC concentration is relatively high in Tehran and HDVs have a major role in emission of this pollutant. A direct correlation between BC concentration and cardiorespiratory related mortality is observed. There are considerable health benefits in reducing BC concentration in this city. Our findings highlight the urgent need to actively curtail emissions of this harmful pollutant. This can be achieved through utilizing control mechanisms such as particulate filters or amending traffic laws.

Particle deposition in the human lung: Health implications of particulate matter from different sources

Although ambient particulate matter or particles have been found to be associated with morbidity and mortality all over the world, specific health effects of particles from different sources need further elucidation. The objective of this work is to predict the deposition of particles from different sources in the human lung. The whole lung, consisting of 24 generations of branches from trachea to alveoli, was approximated using a one-dimensional lumped "trumpet" model with a variable cross-sectional area. The aerosol dynamics equation was numerically solved using a finite difference method to investigate the transport and deposition of particles in the lung model. Particles from various sources were assumed to be different in both size and density. We found that in general, coarse particles (> 2.5 µm) were mainly deposited in the tracheobronchial (TB) region by impaction, and fine particles (< 2.5 µm) were mainly deposited in the pulmonary (P) region by sedimentation and diffusion. However, the coarse particles with low density can be deposited in P region by sedimentation. As a comparison, our results found that soil particles, which are coarse with low density, were deposited in the deep lung more than traffic particles, which are fine with high density. Modeling of particle deposition in the human lung indicated that coarse particles generated by crustal sources may have adverse health effects as strong as those resulting from fine particles generated from combustion sources.

Negative Emotion under Haze: An Investigation Based on the Microblog and Weather Records of Tianjin, China

Nowadays, many big cities are suffering from heavy air pollution and continuous haze weather. Compared with the threat on physical health, the influence of haze on people’s mental health is much less discussed in the current literature. Emotion is one of the most important indicators of mental health. To understand the negative impact of haze weather on the emotion of the people, we conducted an investigation based on historical weather records and microblog data in Tianjin, China. Specifically, an emotional thesaurus was generated with a microblog corpus collected from sample data. Based on the thesaurus, the public emotion under haze was statistically described. Then, through correlation analysis and comparative study, the relation and seasonal variation of haze and negative emotion of the public were well discussed. According to the study results, there was indeed a correlation between haze and negative emotion of the public, but the strength of this relationship varied under different conditions. The level of air pollution and weather context were both important factors that influence the mental effects of haze, and diverse patterns of negative emotion expression were demonstrated in different seasons of a year. Finally, for the benefit of people’s mental health under haze, recommendations were given for haze control from the side of government.

Radiocarbon determination of fossil and contemporary carbon contribution to aerosol in the Pacific Islands

Combustion emissions are of growing concern across all Pacific Island Countries, which account for >10,000 km² of the earth's surface area; as for many other small island states globally. Apportioning emissions inputs for Suva, the largest Pacific Island city, will aid in development of emission reduction strategies. Total suspended particulate (TSP) and fine particulate (PM_2.5) samples were collected for Suva City, a residential area (Kinoya, TSP) and a mainly ocean-influenced site (Suva Point, TSP) from 2014 to 2015. Percentages of contemporary and fossil carbon were determined by radiocarbon analysis (accelerator mass spectrometry); for non‑carbonate carbon (NCC), elemental carbon (EC) and organic carbon (OC). Source contributions to particulate matter were identified and the accuracy of previous emissions inventory and source apportionment studies was evaluated. Suva Point NCC concentrations (2.7 ± 0.4 μg/m³) were four times lower than for City (13 ± 2 μg/m³ in TSP) and Kinoya (13 ± 1 μg/m³ in TSP); demonstrating the contribution of land-based emissions activities in city and residential areas. In Suva City, total NCC in air was 81% (79%-83%) fossil carbon, from vehicles, shipping, power generation and industry; whilst in the residential area, 48% (46%-50%) of total NCC was contemporary carbon; reflecting the higher incidence of biomass and waste burning and of cooking activities. Secondary organic fossil carbon sources contributed >36% of NCC mass at the city and >29% at Kinoya; with biogenic carbon being Kinoya's most significant source (approx. 30% of NCC mass). These results support the previous source apportionment studies for the city area; yet show that, in line with emissions inventory studies, biomass combustion contributes more PM_2.5 mass in residential areas. Hence air quality management strategies need to target open burning activities as well as fossil fuel combustion.

Partitioning of particulate matter and elements of suburban continental aerosols between fine and coarse modes

The results presented in this work demonstrate for the first time a distribution of elements in the spectral analysis of aerosols in the suburban continental Balkan Peninsula. Samples were collected in the suburban area of Belgrade (Serbia) in the period from March 2012 till December 2013. Results presented here are from long-term measurements of masses of size-segregated aerosols and macro- and microelements in the range of PM_0.27-16. The following elements were analyzed: Al, Ag, As, Ba, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Mo, Na, Ni, Pb, Sb, Ti, Tl, V, and Zn; levels of Be, Hg, and Se were under the detection limits in all samples. Average concentrations and time and seasonal variations of particulate matter (PM) as well as element contents and their percentage shares are given. The results showed the domination of particle content around the accumulation mode in the range of 0.53 < Dp < 1.06 μm, but the fractional distribution of elements showed maximal average concentrations in different fractions depending on the origin of each element. Crustal elements (Al, Ca, Fe, Mg, Mn, Ti, etc.) dominated in coarse mode, while anthropogenic elements (As, Cd, Cu, Pb, Sb, etc.) were mainly distributed in fine mode fractions. Some elements, such are As and Ni, were detected in investigated aerosols only occasionally, while others, such as Ca, Fe, and Mg, were detected in all analyzed samples. The application of multivariate analysis (PCA) demonstrated the connection between the elements of similar origin, in fine fractions mainly of anthropogenic origin, while in coarse mode of crustal origin, indicating the resuspension with contribution of about 40%. The contents of some measured elements were compared with their contents in aerosols in some European suburban areas.