Emission reduction of black carbon and polycyclic aromatic hydrocarbons during COVID-19 pandemic lockdown

Polycyclic aromatic hydrocarbons within the vicinity of a scrap-iron smelting plant: indoor-outdoor and seasonal pattern, source, and exposure risk assessment

The growing demand for ferrous metals and abundant scrap materials has fueled Nigeria's scrap-iron smelting industry, leading to hazardous pollutant emissions. This study investigated the concentrations, seasonal and indoor-outdoor variations, origins, and health impacts of polycyclic aromatic hydrocarbons (PAHs) in dust samples around a scrap-iron smelting facility. Analyses of dust samples revealed that high molecular weight PAHs (HMWPAHs) dominated during both seasons, with 5-ring PAHs (34%) contributing most during the rainy season and 3-ring PAHs (36%) during the dry season. Carcinogenic PAHs were more prevalent in the rainy season compared to the dry season. Seven PAH sources were identified, with gasoline combustion being the dominant source during the rainy season and iron and steel production during the dry season. Incremental lifetime cancer risk (ILCR) assessments showed PAH concentrations within safe limits, with dermal contact identified as the primary exposure pathway for both children and adults in the study area.

Source apportionment of particle-bound polycyclic aromatic hydrocarbons (PAHs), oxygenated PAHs (OPAHs), and their associated long-term health risks in a major European city

Many studies have drawn attention to the associations of oxygenated polycyclic aromatic hydrocarbons (OPAHs) with harmful health effects, advocating for their systematic monitoring alongside simple PAHs to better understand the aerosol carcinogenic potential in urban areas. To address this need, this study conducted an extensive PM2.5 sampling campaign in Athens, Greece, at the Thissio Supersite of the National Observatory of Athens, from December 2018 to July 2021, aiming to characterize the levels and variability of polycyclic aromatic compounds (PACs), perform source apportionment, and assess health risk. Cumulative OPAH concentrations (Σ-OPAHs) were in the same range as Σ-PAHs (annual average 4.2 and 5.6 ng m-3, respectively). They exhibited a common seasonal profile with enhanced levels during the heating seasons, primarily attributed to residential wood burning (RWB). The episodic impact of biomass burning was also observed during a peri-urban wildfire event in May 2021, when PAH and OPAH concentrations increased by a factor of three compared to the monthly average. The study period also included the winter 2020-2021 COVID-19 lockdown, during which PAH and OPAH levels decreased by >50 % compared to past winters. Positive matrix factorization (PMF) source apportionment, based on a carbonaceous aerosol speciation dataset, identified PAC sources related to RWB, local traffic (gasoline vehicles) and urban traffic (including diesel emissions), as well as an impact of regional organic aerosol. Despite its seasonal character, RWB accounted for nearly half of Σ-PAH and over two-thirds of Σ-OPAH concentrations. Using the estimated source profiles and contributions, the source-specific carcinogenic potency of the studied PACs was calculated, revealing that almost 50 % was related to RWB. These findings underscore the urgent need to regulate domestic biomass burning at a European level, which can provide concrete benefits for improving urban air quality, towards the new stricter EU standards, and reducing long-term health effects.

Associations of ambient particulate matter and household fuel use with chronic liver disease in China: A nationwide analysis

BACKGROUND

Long-term effects of outdoor and indoor air pollution on chronic liver disease (CLD) remain unclear. Thus, the study was conducted to investigate the relationship between prolonged exposure to ambient particulate matter (PM1, PM2.5 and PM10) and household fuel usage with CLD.

METHODS

Data from the China Health and Retirement Longitudinal Study (CHARLS) covering the years 2011 to 2020 were employed. In the cross-sectional analysis, 16,680 participants were included, while 12,969 participants were enrolled in the longitudinal study. The associations between various sizes of particulate matter and CLD were elucidated using logistic regression model and generalized linear-mixed models. Additionally, the additive effects of ambient particulate matter (PM) levels and the utilization of solid fuels for cooking were investigated, with a comparison of effect sizes between converted and non-converted fuel types.

RESULTS

Over a 10-year follow-up period, 746 (5.75 %) individuals developed CLD. For a 1-year average concentrations, PM1, PM2.5 and PM10 were each linked to a 1.549 (95 %CI:1.522-1.576), 1.296 (95 %CI:1.276-1.317) and 1.134 (95 %CI:1.118-1.150) fold risk of incident CLD per 10 μg/m3 increase, respectively. A similar effect of PM concentrations over a 2-year period on CLD was observed. Moreover, simultaneous exposure to ambient PM and solid fuels is associated with an increased risk of CLD. Those who continue using solid fuels may face a higher risk of CLD compared to individuals who switch to cleaner cooking fuels. Female participants, smokers, and individuals with shorter sleep duration and multiple chronic diseases exhibited slightly stronger effects.

CONCLUSION

Long-term exposure to various sizes of PM (PM1, PM2.5, PM10) has been linked to an elevated risk of CLD incidence. Co-exposure to ambient PM and solid fuels is associated with higher health risks.

Polycyclic aromatic hydrocarbons in indoor mosques dust in Saudi Arabia: Levels, source apportionment, human health and carcinogenic risk assessment for congregators

Mosques are important places for Muslims where they perform their prayers. The congregators are exposed to hazardous pollutants such as polycyclic aromatic hydrocarbons (PAHs) associated with dust. However, studies on PAHs exposure in religious places are scarce. Air-condition filter (ACF) dust can correspond to air quality to a certain extent, since dust particles derived from indoor and outdoor places stick to it. Therefore, the present study aimed to evaluate the 16 EPA PAHs in ACF dust from mosques to determine their levels, profiles, sources and risks. Average Σ16 PAHs concentrations were 1039, 1527, 2284 and 5208 ng/g in AC filter dust from mosques in residential (RM), suburban (SM), urban (UM) and car repair workshop (CRWM), respectively, and the differences were statistically significant (p < 0.001). Based on the molecular diagnostic PAH ratios, PAHs in mosques dust is emitted from local incomplete fuel combustion, as well as complete fossil fuels combustion sources (pyrogenic), petroleum spills, crude and fuel oil, traffic emissions, and other possible sources of industrial emissions in different functional areas. The incremental lifetime cancer risks (ILCRs) values for children and adults across the different types of mosques follow the order: CRWM > UM > SM > RM. ILCRs values for both children and adults were found in order: dermal contact > ingestion > inhalation. The cancer risk levels via ingestion for children were relatively higher than the adults. The values of cancer risk for children and adults via dermal contact and ingestion (except in RM) were categorized in the 'potentially high risk' category (> 10-4). The mean values of total cancer risks (CR) for children (5.74 × 10-3) and adults (5.07 × 10-3) in mosques also exceeded the accepted threat value (>10-4). Finally, it is recommended that regular and frequent monitoring of PAHs should be carried out in mosques to improve the quality and maintain the health of congregators around the globe.

Investigations into the occurrence of polycyclic aromatic hydrocarbons in surface waters of the Narok and Bomet counties of Kenya

Polycyclic aromatic hydrocarbons (PAHs) are a group of emerging chemical pollutants that pose severe health challenges and toxicity to people and aquatic organisms exposed to these pollutants. This study sought to assess the types and levels of PAHs and their eco-toxicity indices in surface waters of Narok and Bomet counties of Kenya, which have witnessed an increase in charcoal-burning activities and vehicular emissions near water bodies. Sampling was done in eight regions of the two counties based on their proximity to PAH sources. Extraction of the water samples was done via a solid-phase mmethod. Seven US Environmental Protection Agency (US EPA) priority PAHs were detected. The concentrations of these PAHs varied from below the limits of detection up to 31.42 µg l-1 for dibenzo[a,h]anthracene. The majority of the PAHs from Narok County were pyrogenic, while those from Bomet were petrogenic based on PAH diagnostic ratios. The surface waters were significantly polluted with dibenzo[a,h]anthracene, with risk quotients above 1.0 in the surface waters, and were found to be hazardous, with hazard quotients above 10.0, thus indicating potential environmental risks. The findings indicate the need for stringent measures to be put in place to mitigate the risks posed by these PAHs.

Insight into the diurnal variations and potential sources of ambient PM2.5-bound polycyclic aromatic hydrocarbons during spring in Northern Taiwan

In recent decades, polycyclic aromatic hydrocarbons (PAHs), the primary organic pollutants associated with particulate matter (PM), have attracted significant attention due to their carcinogenic and mutagenic potential. However, past studies have lacked exploration into the diurnal variation characteristics of PAHs, primarily due to limited analytical technical capabilities. This study utilized a thermal-desorption device coupled with gas chromatography/mass spectrometry (TD-GC/MS) to identify the levels of PAHs in PM2.5 during short periods (3-hr) and aimed to investigate the diurnal variations, possible sources, and potential health risks associated with PM2.5-bound PAHs in northern Taiwan. The mean concentration of total PAHs in PM2.5 was 1.22 ± 0.69 ng m-3 during the sampling period, with high molecular weight PAHs dominating. Source apportionment by the positive matrix factorization (PMF) model indicated that industrial emissions and traffic emissions (57.7 %) were the predominant sources of PAHs, with petroleum volatilization and coal/biomass combustion (42.3 %) making a lesser contribution. Diurnal variations of industrial and traffic emissions showed higher concentrations during traffic rush hours, while petroleum volatilization and coal/biomass combustion displayed higher concentrations at noon. Results from the potential source contribution function (PSCF) and the concentration weighted trajectory (CWT) model suggested that industrial emissions and traffic emissions mostly originated from local sources and were concentrated in the vicinity of the sampling site and the coastal area of western Taiwan. Source-attributed excess cancer risk (ECR) showed that industrial and traffic emissions had the highest cancer risks during morning traffic peak hours (1.69 ×10-5), while petroleum volatilization and coal/biomass combustion reached the maximum at noon (4.75 ×10-6). As a result, efforts to reduce PAH emissions from industrial and vehicle exhaust sources, especially during morning traffic hours, can help mitigate their adverse impact on human health.

Associations between atmospheric PM2.5 exposure and carcinogenic health risks: Surveillance data from the year of lowest recorded levels in Beijing, China

Scant research has pinpointed the year of minimum PM2.5 concentration through extensive, uninterrupted monitoring, nor has it thoroughly assessed carcinogenic risks associated with analyzing numerous components during this nadir in Beijing. This study endeavored to delineate the atmospheric PM2.5 pollution in Beijing from 2015 to 2022 and to undertake comprehensive evaluation of carcinogenic risks associated with the composition of atmospheric PM2.5 during the year exhibiting the lowest concentration. PM2.5 concentrations were monitored gradually in 9 districts of Beijing for 7 consecutive days per month from 2015 to 2022, and 32 kinds of PM2.5 components collected in the lowest PM2.5 concentration year were analyzed. This comprehensive dataset served as the basis for carcinogenic risk assessment using Monte Carlo simulation. And we applied the Positive Matrix Factorization (PMF) method to identity the sources of atmospheric PM2.5. Furthermore, we integrated this source appointment model with risk assessment model to discern the origins of these risks. The findings revealed that the annual average PM2.5 concentration in 2022 stood at 43.1 μg/m3, marking the lowest level recorded. The mean carcinogenic risks of atmospheric PM2.5 exposure calculated at 6.30E-6 (empirical 95% CI 1.09E-6 to 2.25E-5) in 2022. The PMF model suggested that secondary sources (35.4%), coal combustion (25.6%), resuspended dust (15.1%), biomass combustion (14.1%), vehicle emissions (7.1%), industrial emissions (2.0%) and others (0.7%) were the main sources of atmospheric PM2.5 in Beijing. The mixed model revealed that coal combustion (2.41E-6), vehicle emissions (1.90E-6) and industrial emissions (1.32E-6) were the main sources of carcinogenic risks with caution. Despite a continual decrease in atmospheric PM2.5 concentration in recent years, the lowest concentration levels still pose non-negligible carcinogenic risks. Notably, the carcinogenic risks associated with metals and metalloids exceeded that of PAHs. And the distribution of risk sources did not align proportionally with the distribution of PM2.5 mass concentration.

Atmospheric black carbon aerosol: Long-term characteristics, source apportionment, and trends

Black carbon (BC) aerosols play a very significant role in influencing air quality, climate, and human health. Large uncertainties still exist in BC emissions due to limited observations on the relative source contributions of fossil fuel (ff) combustion and biomass (wood fuel, wf) burning. Our understanding of long-term changes in BC emissions, especially their source apportionment, is sparse and limited. For the first time, BC characteristics, its source apportionment into ff and wf components, and their trends measured using a multi-wavelength aethalometer over an urban location (Ahmedabad) in India covering a 14 year period (2006-2019) are comprehensively investigated. The average contributions of eBCff and eBCwf concentrations to total eBC are 80 % and 20 %, respectively, which highlights the dominance of emissions from fossil fuel combustion processes. A statistically significant increasing trend in eBC and eBCff mass concentrations at the rate of 11 % and 29%yr-1, respectively, and a decreasing trend in eBCwf concentration at the rate of 36%yr-1 are detected. The study reveals a significant decrease in biomass (wood fuel) burning emissions over the past decade and an increase in emissions from fossil fuel combustion. However, the rates of increase and decrease in eBCff and eBCwf are different, which indicate that rapid urbanization led to an increase in anthropogenic emissions, whereas an increase in usage of non-polluting fuel led to a decreasing trend in wood burning contribution. During weekdays and weekends, eBC and eBCff mass concentrations did not exhibit any statistically significant trends. However, eBCwf concentration shows a statistically significant decreasing trend during weekdays 34%yr-1 and weekends 38%yr-1. Globally, several countries are adopting various strategies and mitigation policies to improve air quality; however, significant gaps exist in their implementation towards achieving cleaner air and less polluted environment. This comprehensive study is relevant for understanding the impact of urbanization and devising better BC emission control policies.

Organic matter sources and distribution along land-use gradient in a Himalayan foothills River: Insights from molecular markers

The analysis of hydrocarbon biomarkers in surface sediments along the Markanda River in the foothills of the Indian Himalayas was conducted to gain insights into the distribution and composition of organic matter (OM) within the sediments. This investigation is essential for comprehending how anthropogenic changes are influencing the OM dynamics in river systems. The study involved identification and quantification of various compound groups such as n-alkanes, hopanes, steranes, polycyclic aromatic hydrocarbons (PAHs), linear alkyl benzenes (LABs) and phthalate esters along with their respective parametric ratios. The variation in distribution of n-alkanes and associated indices (odd-even carbon number predominance (OEP), average chain length (ACL), terrigenous to aquatic ratio (TAR), carbon preference index (CPI), and natural n-alkanes ratio (NAR)) were used to distinguish the natural source of organic content from those influenced by anthropogenic contamination. The detection of petroleum contamination was indicated by the presence of prominent unresolved complex mixtures (UCM) as well as specific petroleum biomarkers such as hopanes, diasteranes, and steranes. The study revealed varying concentrations of the analyzed organic pollutants, with the average of PAHs at 24.6 ng/g dw, LABs at 18.1 ng/g dw, and phthalates at 8.3 μg/g dw. The variability in concentration of the investigated compound groups across different locations indicated spatial heterogeneity, and the land use patterns appears to modulate the sources of OM in surface sediments. The source contribution of PAHs and phthalates determined by positive matrix factorization (PMF) shows the predominant sources of the anthropogenic hydrocarbons were linked primarily to petroleum/petroleum-derived products emissions, industrial discharges, cultural practices and common household waste/sewage disposal. This analysis provides insights for developing mitigation strategies and informing relevant policy changes globally, thereby contributing to the broader understanding of anthropogenic impacts on water ecosystems.

Melanin-mediated accumulation of polycyclic aromatic hydrocarbons in human hair: Insights from biomonitoring and cell exposure studies

While human hair is widely used to monitor micro-organic contaminants (MOCs), their incorporation mechanisms are poorly understood. Melanin, known to facilitate the accumulation of drugs in hair, hasn't been studied in the field of MOCs. Here, polycyclic aromatic hydrocarbons (PAHs), a class of priority MOCs, were investigated through hair biomonitoring as well as cell exposure experiments. PAH concentrations and melanin contents were measured in black and white hairs from the same individual. The results showed that five dominant PAHs (phenanthrene, fluoranthene, pyrene, benzo[a]anthracene and chrysene) in black hair (0.66 ng/g - 35.1 ng/g) were significantly higher than those in white hair (0.52 ng/g - 29.6 ng/g). Melanin contents in black hair (14.9 - 48.9 ng/g) were markedly higher than in white hair (0.35 - 2.15 ng/g) and were correlated to PAH concentrations, hinting melanin-mediated accumulation of PAHs in hair. The in vitro experiment using murine melanoma cells demonstrates that PAH levels in cells were affected by melanin, suggesting the affinity of melanin to PAHs. Both biomonitoring and cell exposure experiment implicate the pivotal role of melanin in PAH accumulation in hair. Therefore, to ensure the accuracy of hair biomonitoring for MOCs, attention must be paid to the melanin content uniformity.

Polycyclic aromatic hydrocarbon (PAH) accumulation in selected medicinal plants: a mini review

The use of plant-based products in healthcare systems has experienced a tremendous rise leading to a substantial increase in global demand. However, the quality and effectiveness of such plant-based treatments are often affected due to contamination of various pollutants including polycyclic aromatic hydrocarbons (PAHs). Like other plants, medicinal plants also uptake and accumulate PAHs when exposed to a contaminated environment. The consumption of such medicinal plants and/or plant-based products causes negative effects on health rather than providing any therapeutic advantages. Unfortunately, research focusing on PAH accumulation in medicinal plants has received very limited attention. This review discusses a sizable number of literature regarding the concentration of sixteen priority PAH pollutants as recognised by the US Environmental Protection Agency (USEPA) in different medicinal plants. The review also highlights the risk assessment of cancer associated with some medicinal plants in terms of benzo[a]pyrene (BaP) equivalent concentrations.

Assessing the effect of COVID 19 lockdowns on the composition of organic compounds and potential source of PM2.5 in Hanoi, Vietnam

The ambient air quality during COVID-19 lockdowns has been improved in many cities in the world. This study is to assess the changes in persistent organic pollutants in PM2.5 during the COVID-19 lockdown in Hanoi. Individual organic species in PM2.5 ((e.g., polycyclic aromatic hydrocarbons (PAHs), polychlorobiphenyls (PCBs), and organochlorine pesticides (OCPs)) were measured in an urban residential area in Hanoi from before the March 10th to April 22nd, 2020, including before the partial lockdown (BL) and the partial lockdown (PL) phases. During the PL phase, the concentration of Σ14PAHs and Σ28PCBs was reduced by 38 and 52% compared with the BL period, respectively. The diagnostic ratio method implied that the sources of PAHs within the PL phase had a less effect on traffic and industrial activities than in the BL phase. The characteristic ratio method indicated that PCBs were mixed by commercial product and combustion process in both the BL and the PL periods, however, the source of PCBs in the BL phase was influenced by municipal waste incineration more than those in the PL phase. The decreasing concentration of Σ20OCPs during the partial lockdown was attributed to the restriction of human activities during the quarantine period. The results suggested that the source of OCPs was probably derived from the usage of pesticides in current and, historical degradation or the transportation of pesticides from the soil to the atmosphere.

Impact of occupational noise exposure on the hearing level in hospital staffs: a longitudinal study

The study aimed to evaluate the impact of occupational noise on hearing loss among healthcare workers using audiometry. A longitudinal study was conducted with a six-month follow-up period in a hospital with 21 participants, divided into high-noise-exposure (HNE) and low-noise-exposure (LNE) groups. Mean noise levels were higher in the HNE group (70.4 ± 4.5 dBA), and hearing loss was measured using pure-tone audiometry at baseline and follow-up. The HNE group had significantly higher mean threshold levels at frequencies of 0.25 kHz, 0.5 kHz, 4.0 kHz, and an average of 0.5, 1, 2, and 4 kHz (all p-values < 0.05) after the follow-up period. After adjusting for confounding factors, the HNE group had significantly higher hearing loss levels at 0.25 kHz, 0.5 kHz, and average frequencies of 0.5, 1, 2, and 4 kHz compared to the LNE group at the second measurement. Occupational noise levels above 65 dBA over six months were found to cause significant threshold changes at frequencies of 0.25 kHz, 0.5 kHz, and an average of 0.5-4.0 kHz. This study highlights the risk of noise-induced hearing loss among healthcare workers and emphasizes the importance of implementing effective hearing conservation programs in the workplace. Regular monitoring and assessment of noise levels and hearing ability, along with proper use of personal protective equipment, are crucial steps in mitigating the impact of occupational noise exposure on the hearing health of healthcare workers.

Multimedia distribution, dynamics, and seasonal variation of PAHs in Songhua wetland: Implications for ice-influenced conditions

The knowledge of polycyclic aromatic hydrocarbons (PAHs) in wetlands remains limited. There is a research need for the dynamics between interfaces of multimedia when ice is present in this fragile ecosystem. In this study, sediment, open-water, sub-ice water, and ice samples were collected from the Songhua wetland to study the behaviors of PAHs with and without influences from ice. The concentration of all individual PAHs in sub-ice water (370-1100 ng/L) were higher than the open-water collected from non-ice-covered seasons (50-250 ng/L). Enrichment of PAHs in the ice of wetland was found, particularly for high-molecular-weight PAHs (HMW). This could be attributed to the relatively lower polarity of hydrocarbons compounds, making them more likely to remain in the ice layer during freezing. Source assessments reveal common sources for sub-ice water and ice, which differ from those in the open water in non-ice-covered seasons. This difference is primarily attributed to heating activities in the Harbin during winter. The average percentage contributions were 79% for sub-ice water and 36% for ice related to vehicle exhausts and coal combustion. Additionally, wood burning contributed 25% to sub-ice water and 62% to ice. Sediment in the wetland was found to serve as a final deposit particularly for heavier PAHs, especially those with 6 rings. Sediment also has the potential to act as a source for the secondary emission of low-molecular-weight PAHs (LMW) congeners into the water. PAHs in wetland displayed low ecological risk, while HMW PAHs with relative higher ecological risk is recommended to be further monitored.

Biochars assisted phytoremediation of polycyclic aromatic hydrocarbons contaminated agricultural soil: Dynamic responses of functional genes and microbial community

A biochar-intensified phytoremediation experiment was designed to investigate the dynamic effects of different biochars on polycyclic aromatic hydrocarbon (PAH) removal in ryegrass rhizosphere contaminated soil. Maize and wheat straw biochar pyrolyzed at 300 °C and 500 °C were amended into PAH-contaminated soil, and then ryegrass (Lolium multiflorum L.) was planted for 90 days. Spearman's correlations among PAH removal, enzyme activity, abundance of PAH-ring hydroxylating dioxygenase (PAH-RHDα), and fungal and bacterial community structure were analyzed to elucidate the microbial degradation mechanisms during the combined remediation process. The results showed that 500 °C wheat straw biochar had higher surface area and more nutrients, and significantly accelerated the phytoremediation of PAHs (62.5 %), especially for high molecular weight PAH in contaminated soil. The activities of urease and dehydrogenase and the abundance of total and PAH-degrading bacteria, which improved with time by biochar and ryegrass, had a positive correlation with the removal rate of PAHs. Biochar enhanced the abundance of gram-negative (GN) PAH-RHDα genes. The GN PAH-degraders, Sphingomonas, bacteriap25, Haliangium, and Dongia may play vital roles in PAH degradation in biochar-amended rhizosphere soils. Principal coordinate analysis indicated that biochar led to significant differences in fungal community structures before 30 days, while the diversity of the bacterial community composition depended on planting ryegrass after 60 days. These findings imply that the structural reshaping of microbial communities results from incubation time and the selection of biochar and ryegrass in PAH-contaminated soils. Applying 500 °C wheat straw biochar could enhance the rhizoremediation of PAH-contaminated soil and benefit the soil microbial ecology.

New prospects of environmental RNA metabarcoding research in biological diversity, ecotoxicological monitoring, and detection of COVID-19: a critical review

Ecosystems are multifaceted and complex systems and understanding their composition is crucial for the implementation of efficient conservation and management. Conventional approaches to biodiversity surveys can have limitations in detecting the complete range of species present. In contrast, the study of environmental RNA (eRNA) offers a non-invasive and comprehensive method for monitoring and evaluating biodiversity across different ecosystems. Similar to eDNA, the examination of genetic material found in environmental samples can identify and measure many species, including ones that pose challenges to traditional methods. However, eRNA is degraded quickly and therefore shows promise in detection of living organisms closer to their actual location than eDNA methods. This method provides a comprehensive perspective on the well-being of ecosystems, facilitating the development of focused conservation approaches to save at-risk species and uphold ecological equilibrium. Furthermore, eRNA has been recognized as a valuable method for the identification of COVID-19 in the environment, besides its established uses in biodiversity protection. The SARS-CoV-2 virus, which is accountable for the worldwide epidemic, releases RNA particles into the surrounding environment via human waste, providing insights into the feasibility of detecting it in wastewater and other samples taken from the environment. In this article, we critically reviewed the recent research activities that use the eRNA method, including its utilization in biodiversity conservation, ecological surveillance, and ecotoxicological monitoring as well as its innovative potential in identifying COVID-19. Through this review, the reader can understand the recent developments, prospects, and challenges of eRNA research in ecosystem management and biodiversity conservation.

Assessment of ambient air quality in relation to the burning of firecrackers during the festival of Diwali: A case study of Jodhpur City (India)

The study attempts to examine the impact of firework activities during Diwali Festival on ambient air quality of Jodhpur city. Air quality parameters particulate matter of diameter 10 μm (PM10), particulate matter of diameter 2.5 μm (PM2.5), sulfur dioxide (SO2), nitrogen dioxide (NO2) and heavy metals in PM2.5 like Pb, Ni, Ba, Al, As and Sr are monitored at two locations, for 15 days, starting from 7 days before the festival of Diwali, on the day of the festival (Diwali) and 7 days after Diwali. On the occasion of Diwali, it was discovered that the 24-h average levels of various pollutants were significantly elevated compared to regular days preceding the festival. Specifically, at the HBO site, the concentrations were notably increased, with sulfur dioxide (SO2) reaching 5.62 times higher, nitrogen dioxide (NO2) at 3 times higher, particulate matter of diameter 10 μm (PM10) at 2.35 times higher, and particulate matter of diameter 2.5 μm (PM2.5) at 1.01 times higher than the usual levels before Diwali. Similarly, at the PTMM site, there were substantial elevations in pollutant concentrations during Diwali compared to pre-festival days, with SO2 registering 2.53 times higher, NO2 at 2.37 times higher, PM2.5 at 1.9 times higher, and PM10 at 1.57 times higher levels than normal. Concentration of Al, Ba, Sr and Pb at HBO site and Al at PTMM site was highest on Diwali day. Air quality index which was in good category on normal days before Diwali, fell into poor category starting from the day before Diwali and remain in poor category on normal days after Diwali. The result indicates the worsening of ambient air quality during Diwali which can adversely impact the human health in terms of various respiratory complications.

HPLC Analysis and Risk Assessment of 15 Priority PAHs in Human Blood Serum of COPD Patient from Urban and Rural Areas, Iasi (Romania)

One of the leading risk factors for environmental health problems is air pollution. The World Health Organization (WHO) reports that this risk factor is associated with one of every nine deaths worldwide. Epidemiological studies conducted in this field have shown a solid connection between respiratory pathology and polycyclic aromatic hydrocarbon (PAH) exposure. COPD and asthma are respiratory diseases that were shown to have a strong association with exposure to PAHs. The purpose of the present study was to assess the serum levels of 15 PAHs in 102 COPD patients and to evaluate the results according to the residence environment of the investigated subjects. Analyses were carried out using a high-performance liquid chromatograph Nexera X2-Shimadzu Japan, which was equipped with an LC-30AD pump and an SIL-30AC autosampler. Spiked matrices, procedure blanks, spiked controls, and calibration standards in the acetonitrile were used as quality-assurance samples. Benzo(a)pyrene is the main representative of PAHs and was determined in higher concentrations in subjects with COPD versus the control group from the urban area (0.90/0.47 ng/mL) and rural area (0.73/0.44 ng/mL). The values obtained for the Benzo(a)pyrene-equivalent factor indicate a higher carcinogenic potential for patients diagnosed with COPD in urban areas compared to those in rural areas. These results could be due to traffic and vehicle emissions. This research identifies the need for legislative action to decrease semi-volatile organic compounds, especially PAHs, mainly in urban cities, in order to improve environmental management and health conditions.

Integrative assessment of urban dust polycyclic aromatic hydrocarbons using ground and satellite data in Iran

Recently, for quick urbanization and industrialization, pollutants, especially urban dust, have posed many threats to the human environment. Polycyclic aromatic hydrocarbons (PAHs) are regarded as the main dangerous pollutants that are widespread, persistent, and carcinogenic. The present work aimed to investigate the contamination and sources of PAHs, as well as to assess the risk of cancer for 16 priority PAHs, in urban dust samples in Ahvaz, Isfahan, and Shiraz cities in Iran. We measured PAH concentrations by gas chromatography-mass spectrometry (GC-MS). The average concentrations of the 16 PAHs in Ahvaz, Isfahan, and Shiraz were 6215.11, 7611.03, and 7810.37 μg kg-1, respectively. The domination of low-molecular-weight (LMW) PAHs was observed in Ahvaz, while maximum contribution was observed for high-molecular-weight (HMW) PAHs in Esfahan and Shiraz. For PAHs' source identification, diagnostic ratio, correlation analysis, clustering, and positive matrix factorization (PMF) model were used. PAHs had a combustion (coal and wood, oil, fossil fuels) and gasoline/diesel engine emissions in all cities. Comparative studies suggest that the PAH compounds' level is higher in the research area than in other countries, except for China and India. Also, the pollution of urban dust PAHs has increased over time compared to previous studies in the same cities. The cancer risk from exposure to dust contaminated with PAHs was assessed using the Incremental Lifetime Cancer Risk (ILCR) model. According to the findings, a high risk of exposure to cancer was observed in Ahvaz, Isfahan, and Shiraz. However, compared to adults, children are at higher risk of cancer in their daily lives via dermal contact and unconscious ingestion. Based on the ILCR values, the risk of cancer is in the order of Shiraz > Isfahan > Ahvaz. To assess air pollutants and their effects on urban dust, TROPOMI onboard the Sentinel-5P data were used in the studied cities during 2018-2021. The results show that Ahvaz has different high levels of CO compared to the other 2 cities. Also, Isfahan has different high levels of NO2 compared to the other 2 cities, but Shiraz has different low levels of O3. According to satellite time series data, the trend of the Aerosol Absorbing Index (AAI) has been increasing, while there was a decreasing trend in AAI from the beginning of the COVID-19 pandemic until 12 months later. Therefore, the natural and anthropogenic sources of urban dust PAHs have been increasing in all studied cities. Our findings show that PAH compounds in urban dust pose a significant threat to human health. Therefore, strategic management and planning are vital in reducing urban dust pollution.

Synergistic association of long-term ozone exposure and solid fuel use with biomarkers of advanced fibrosis

This study aims to explore the association of combined exposure to cooking fuel type and ambient ozone (O3) levels with hepatic fibrosis indices among rural adults. A total of 21,010 participants were derived from the Henan Rural Cohort. Information regarding cooking fuel type was collected through a questionnaire, and the concentration of ground-level O3 for each subject was obtained from the Tracking Air Pollution in China (TAP) dataset. A generalized linear model was used to examine the independent association of cooking fuel type or O3 exposure with hepatic fibrosis indices (FIB-4, APRI, and AST/ALT), and their possible interactions with advanced fibrosis were conducted. Compared to clean fuel users, solid fuel users had increased the risk of advanced fibrosis, the adjusted odds ratio (OR) of its assessment by FIB-4 1.240 (1.151, 1.336), by APRI 1.298 (1.185, 1.422), and by AST/ALT 1.135 (1.049, 1.227), respectively. Compared to low O3 exposure, the adjusted ORs of advanced fibrosis assessed by FIB-4, APRI, and AST/ALT in women with high O3 exposure were correspondingly 1.219 (1.138, 1.305), 1.110 (1.017, 1.212), and 0.883 (0.822, 0.949). The adjusted ORs of advanced fibrosis assessed by FIB-4, APRI, and AST/ALT for solid fuel users with high O3 exposure relative to clean fuel users with low O3 exposure in women were 1.557 (1.381, 1.755), 1.427 (1.237, 1.644), and 0.979 (0.863, 1.108), respectively. Significant additive effect of O3 exposure and solid fuel use on FIB-4-defined advanced fibrosis was observed in women, which was quantified by RERI (0.265, 95%CI: 0.052, 0.477), AP (0.170 95%CI: 0.045, 0.295), and SI (1.906, 95%CI: 1.058, 3.432). Solid fuel users with high O3 exposure were significantly associated with elevated hepatic fibrosis indices among rural women, suggesting that poor air quality may induce hepatocellular injury, and women might be more vulnerable to air pollution. The findings indicate that using cleaner fuels in cooking is an effective measure to maintain sustainable development of the environment and gain beneficial effect on human health. Clinical trial registration: The Henan Rural Cohort Study has been registered at the Chinese Clinical Trial Register (registration number: ChiCTR-OOC-15006699). Date of registration: 06 July 2015. http://www.chictr.org.cn/showproj.aspx?proj=11375.

Spatiotemporal variability and health risk assessment of PM2.5 and NO2 over the Indo-Gangetic Plain: A three years long study (2019-21)

Studying the spatiotemporal variability of pollutants is necessary to identify the pollution hotspots with high health risk and enable the agencies to implement pollution abatement strategies in a targeted manner. Present study reports the spatio-temporal variability and health risk assessment (HRA) of PM2.5 (Particulate matter with aerodynamic diameter <2.5μm) and NO2 over IGP from 2019-2021. The HRA is expressed as passively smoked cigarettes (PSC) for four different health outcomes i.e., low birth weight (LBW), percentage decreased lung function (DLF) in school aged children, lung cancer (LC), and cardiovascular mortality (CM). The findings confirm very high PM2.5 and NO2 mass concentrations and high health risk over middle IGP and Delhi as compared to upper and lower IGP. Within Delhi, north Delhi region is the most polluted and at highest risk as compared to central and south Delhi. The health risk associated with PM2.5 over IGP is highest for DLF, equivalent to 21.63 PSCs daily, followed by CM (11.69), LBW (8.27) and LC (6.94). For NO2, the health risk is highest for DLF (3.09 PSCs) and CM (2.95), followed by LC (1.47) and LBW (1.04). PM2.5 and NO2 concentrations, along with the associated health risks, are highest during the post-monsoon and winter seasons and lowest during the monsoon season.

A novel biomass pyrogenic index and its application coupled with black carbon for improving polycyclic aromatic hydrocarbon source identification

To accurately subdivide the sources of polycyclic aromatic hydrocarbons (PAHs), the composition characteristics of 36 total polycyclic hydrocarbons (T-PAHs; 16 parent PAHs and 20 alkylated PAHs [A-PAHs]) in biomass-residue samples were analyzed. A novel biomass pyrogenic index (BPI) was defined based on A-PAH-fingerprinting differences between biomass-combustion and petroleum sources of PAHs and the sum of the concentrations of pyrene, fluoranthene, benzo[a]anthracene, and alkylated homologs) divided by the ∑value of EPA PAHs with 2-3 rings. BPIs of < 0.5 and > 0.5 indicated that the PAHs originated mainly from biomass combustion and petroleum, respectively. And the ∑targeted A-PAH pairs influencing the BPI/black carbon (BC) ratio was used to identify PAH sources in surface-sediment samples, using 0.5 as the threshold to distinguish between different sources across the strait. The columnar sediments were used to verify the accuracy of two source-identification methods. The results revealed that the main PAH sources changed since 2005, which is highly consistent with those obtained using positive matrix factors and a changing trend in the main types of local energy use. These results highlight the significance of A-PAHs in accurately identifying PAH sources and suggest that applying compositional differences in BC from different sources for PAH-source identification merits further study.

Comparison of pollution status and source apportionment for PCBs and OCPs of indoor dust from an industrial city

In this study, the pollution status of polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) was investigated in indoor and outdoor dust from three different functional areas of Hefei, China. The relationship between the concentrations of PCBs and OCPs and different influencing factors in dwellings was studied. The results showed that the concentrations of PCBs and OCPs were higher in samples from dwellings with higher smoking frequency, lower cleaning frequency, higher floors and smaller household size. The results of Spearman's correlation coefficient analysis indicated that PCBs and OCPs were not consistently associated with each other, while sources of low-chlorinated PCBs and high-chlorinated PCBs were different. Scanning electron microscopy (SEM) shows the shape of indoor dust was a mixture of blocky, flocculated, spherical structures, and irregular shapes. The results of principal component analysis (PCA) and positive matrix factorization model (PMF) showed that the PCBs and OCPs of indoor dust came from both indoor and outdoor sources between local and regional transport. Carbon (δ¹³C) and Nitrogen (δ¹⁵N) stable isotope results indicate or show that the indoor dust (δ¹³C: - 24.37‰, δ¹⁵N: 6.88‰) and outdoor dust (δ¹³C: - 12.65‰, δ¹⁵N: 2.558‰) is derived from fossil fuel, coal combustion, road dust, fly ash, C4 biomass and soil. Potential source contribution factor (PSCF) and concentration weighted-trajectory analysis suggest that sources of pollutants were local and regional transport from surrounding provinces and marine emissions. The average daily dose (adult: 8.20E-04, children: 2.37E-03) of pollutants and the carcinogenic risks (adult: 1.23E-02, children: 2.65E-02) were relatively greater for children than adults. This study demonstrates the utility of SEM to characterize indoor dust morphology while combining PMF, PSCF, and stable isotope methods in identifying indoor PCBs and OCPs sources and regions.

Occurrence and source of PAHs in Miankaleh International Wetland in Iran

We examined the occurrence and sources of 16 priority PAHs in the water and sediment samples of the Miankaleh Wetland (Coastal Biosphere Reserve), famous for harbouring huge flocks of migrating birds. The water and sediment samples collected from various locations were visualized and processed using a self-organizing map, positive matrix factorization and GIS. All the sediment samples, and >90% of the water samples, showed some degree of PAHs contamination. Higher PAH levels occur near the Chopoghi Channel, powerplants, sewage outfalls, and near fishing operations. Compared with previous study in this area, the PAHs concentration in the sediments of aquatic ecosystem of Miankaleh Wetland is increasing. The levels of PAH contamination seem too low to account for the mass deaths of migratory birds, and botulinus contamination seems the likely cause. Fugacity calculations show that the sediments act as a sink for PAHs. According to PMF and SOM analyses, three origins of PAHs were recognized: (i) fossil fuel and vehicular emissions with high-molecular weight PAHs (4-5 ring); (ii) municipal and industrial sewages characterized by low-molecular weight PAHs (2-3 ring) typical of petrogenic sources; and (iii) port activity characterized by prevalence of petrogenic influence and petroleum-related activities (combustion PAHs and low-molecular weight PAHs) consistent with port activity. This wetland needs serious attention because of continuous input of pollutants. The results and the methods used in this study may assist in improving coastal wetlands management.

Concentration and size distribution of atmospheric particles in southern Italy during COVID-19 lockdown period

Many countries imposed lockdown (LD) to limit the spread of COVID-19, which led to a reduction in the emission of anthropogenic atmospheric pollutants. Several studies have investigated the effects of LD on air quality, mostly in urban settings and criteria pollutants. However, less information is available on background sites, and virtually no information is available on particle number size distribution (PNSD). This study investigated the effect of LD on air quality at an urban background site representing a near coast area in the central Mediterranean. The analysis focused on equivalent black carbon (eBC), particle mass concentrations in different size fractions: PM_2.5 (aerodynamic diameter D_a < 2.5 μm), PM₁₀ (D_a < 10 μm), PM_10-2.5 (2.5 < D_a < 10 μm); and PNSD in a wide range of diameters (0.01-10 μm). Measurements in 2020 during the national LD in Italy and period immediately after LD (POST-LD period) were compared with those in the corresponding periods from 2015 to 2019. The results showed that LD reduced the frequency and intensity of high-pollution events. Reductions were more relevant during POST-LD than during LD period for all variables, except quasi-ultrafine particles and PM_10-2.5. Two events of long-range transport of dust were observed, which need to be identified and removed to determine the effect of LD. The decreases in the quasi-ultrafine particles and eBC concentrations were 20%, and 15-22%, respectively. PM_2.5 concentration was reduced by 13-44% whereas PM_10-2.5 concentration was unaffected. The concentration of accumulation mode particles followed the behaviour of PM_2.5, with reductions of 19-57%. The results obtained could be relevant for future strategies aimed at improving air quality and understanding the processes that influence the number and mass particle size distributions.

Sex-specific effect of urinary metabolites of polycyclic aromatic hydrocarbons on thyroid profiles: results from NHANES 2011-2012

The current study aims to evaluate the associations between 10 urinary polycyclic aromatic hydrocarbon (PAH) metabolites and thyroid profiles. The levels of 10 PAH metabolites and thyroid profiles were obtained from National Health and Nutrition Examination Survey (NHANES) 2011-2012. Spearman analysis was utilized to evaluate the correlation coefficients among these 10 PAH metabolites. Multivariate linear and logistic regression models assessed the relationship between urinary PAH metabolite levels, thyroid hormones, and thyroid autoantibodies after adjusting potential confounders. Stratified analysis by gender was performed to evaluate sex-specific effect of urinary metabolites of PAH on thyroid profiles. One thousand six hundred forty-five eligible adult participants with complete research data were enrolled. Of note, the concentrations of the majority of urinary PAH metabolites were remarkedly higher in females compared with males. 2-hydroxyfluorene (2-FLU) was associated with higher total triiodothyronine (T3) levels in whole population (β = 2.113, 95% CI 0.339-3.888). In males, positive associations were observed in 1-hydroxynaphthalene (1-NAP) and free thyroxine (T4) (β = 0.0002, 95% CI 0.0000-0.0004). 2-FLU was also found positively associated with total T3 (β = 2.528, 95% CI 0.115-4.940) in male subjects. While in female participants, 2-hydroxynaphthalene (2-NAP) was associated with free T3 (β = 0.002, 95% CI 0.000-0.005). 2-FLU was associated with total T3 (β = 2.683, 95% CI 0.038-5.328), free T3 (β = 0.050, 95% CI 0.012-0.087), and total T4 (β = 0.195, 95% CI 0.008-0.382). 2-Hydroxyphenanthrene (2-OHP), 1-hydroxypyrene (1-HP), and 9-hydroxyfluorene (9-FLU) were all positively related to total T3 levels, and the corresponding coefficients were 16.504, 6.587, and 3.010. 9-FLU was also associated with free T3 (β = 0.049, 95% CI 0.008-0.090). No statistical significances were found between PAH metabolite levels and increased prevalence of increased thyroglobulin antibody (TgAb)/thyroid peroxidase antibody (TPOAb) when PAH metabolites were treated as continuous variables. Meanwhile, in the quartile analyses, increased prevalence of elevated TgAb was observed in participants with quartile 2 2-NAP compared with lowest quartile (OR = 1.753, 95% CI 1.021-3.008). Male subgroup analyses indicated that increased prevalence of elevated TgAb was observed in higher quartile of 1-NAP, 2-NAP, and 3-hydroxyfluorene (3-FLU). Increased prevalence of elevated TPOAb was associated with higher 2-NAP quartile. However, in subgroup analysis of females, no statistical significances were found between PAH quartiles and increased TgAb/TPOAb. Significant correlations were found among these 10 PAH metabolites. In conclusion, the cross-sectional study indicated that exposure to PAH might disturb the concentrations of thyroid hormones and thyroid autoantibodies. It is noteworthy that significant differences existed in males and females. Further prospective research is warranted to explore the causal relationship and underlying mechanism of PAH exposure on thyroid dysfunction.

Improving performance of deep learning predictive models for COVID-19 by incorporating environmental parameters

The Coronavirus disease 2019 (COVID-19) pandemic has severely crippled the economy on a global scale. Effective and accurate forecasting models are essential for proper management and preparedness of the healthcare system and resources, eventually aiding in preventing the rapid spread of the disease. With the intention to provide better forecasting tools for the management of the pandemic, the current research work analyzes the effect of the inclusion of environmental parameters in the forecasting of daily COVID-19 cases. Three univariate variants of the long short-term memory (LSTM) model (basic/vanilla, stacked, and bi-directional) were employed for the prediction of daily cases in 9 cities across 3 countries with varying climatic zones (tropical, sub-tropical, and frigid), namely India (New Delhi and Nagpur), USA (Yuma and Los Angeles) and Sweden (Stockholm, Skane, Uppsala and Vastra Gotaland). The results were compared to a basic multivariate LSTM model with environmental parameters (temperature (T) and relative humidity (RH)) as additional inputs. Periods with no or minimal lockdown were chosen specifically in these cities to observe the uninhibited spread of COVID-19 and explore its dependence on daily environmental parameters. The multivariate LSTM model showed the best overall performance; the mean absolute percentage error (MAPE) showed an average of 64% improvement from other univariate models upon the inclusion of the above environmental parameters. Correlation with temperature was generally positive for the cold regions and negative for the warm regions. RH showed mixed correlations, most likely driven by its temperature dependence and effect of allied local factors. The results suggest that the inclusion of environmental parameters could significantly improve the performance of LSTMs for predicting daily cases of COVID-19, although other positive and negative confounding factors can affect the forecasting power.

Centennial records of Polycyclic aromatic hydrocarbons and black carbon in Altay Mountains peatlands, Xinjiang, China

Black carbon (BC) is an important inert carbon component in the cycling process of surface carbon. Polycyclic aromatic hydrocarbons (PAHs) are a kind of thick cyclic organic compounds with carcinogenic, teratogenic, and mutagenic effects. The incomplete burning process of biomass and carbolic fuel is the important source of their co-occurrence. This study collected a 60-cm peat core from the Jiadengyu (JDY), Altay Mountain. The core was dated using the 210Pb and 137Cs methods. The results showed BC, total organic carbon, and PAHs of the JDY peat core to be 1.14–72.6 mg g−1, 17.09–47.2%, and 260.58–1,610.77 ng·g−1, respectively. δ13CBC was between −31.5 and − 29.4‰ (mean of −30.56‰). The results of scanning electron microscopy (SEM) indicated irregular or lumpy peat BC particles, retaining a plant fiber structure. δ13CBC, ratios of PAHs, and the SEM revealed that the BC to be the dominant source of biomass combustion in the peatland. BC showed an increasing trend between 1950 and 1980, after which it decreased. The discrepancy between the change in BC and δ13CBC from the national pattern of BC emission likely reflects the effect of local agricultural exploration, and thus an increase in crop burning.

Temporal and spatial pattern of dust storms, their polycyclic aromatic hydrocarbons, and human health risk assessment in the dustiest region of the world

This study evaluated the concentration and health risks of polycyclic aromatic hydrocarbons (PAHs) in Abadan City under 4 different climatic conditions: normal days, dusty days, dust with northwesterly winds, and dust with southeasterly winds. It also determined the sources of aromatics and discussed the relationship between meteorological parameters and PAH concentrations. The spatiotemporal distribution of dust in the area was determined using the HYSPLIT (hybrid single-particle Lagrangian integrated trajectory) back trajectory model, moderate resolution imaging spectroradiometer (MODIS) images. For this purpose, sampling was performed for 70 days using an Omni device. The concentrations of 16 PAHs (USEPA) ranged from 46.22 to 90.96 ng/m³. The highest concentration of high molecular weight (HMW) PAHs was 4-6 rings, of which 4 rings were predominant in all samples. PAH sources were identified using diagnostic ratios and principal component analysis (PCA), and it was shown that PAHs mainly originate from a mixture of sources, including vehicular emissions, petrol emissions, and traffic. Wind speed was negatively correlated with dust, except on dusty days. This result indicates a decrease in PAH concentrations when wind speed increases. On the other hand, the dust correlation with PAH was positive on normal days, but a negative correlation was observed on dusty days. This result was due to the lower concentration of PAHs from natural resources (such as dust source areas) vs. human resources (such as traffic and industry). PAH health risk assessment in Abadan City showed that the risk of carcinogenesis was higher on normal days and through skin contact. The probability of incremental lifetime cancer risk (ILCR) in all sampling conditions was potential in terms of carcinogenic risk (10^-4-10^-6). As a critical risk factor, relevant authorities should prevent, control, and reduce it.

Seasonal distribution of PM2.5-bound polycyclic aromatic hydrocarbons as a critical indicator of air quality and health impact in a coastal-urban region of Poland

This study focuses on the inter-seasonal distribution and variability of thirteen native PAHs adsorbed onto respirable PM_2.5 fraction collected in a coastal-urban region of northern Poland, in 2019. The backward trajectory analysis and several diagnostic ratios were applied to determine seasonal profiles of PAH congeners and their major sources in airborne samples. The annual cumulative mean value of total PAHs in PM_2.5 was 6.92 ± 10.1 ng m^-3, varying in the following range: 0.32 ng m^-3 (May) - 68.57 ng m^-3 (January). Seasonal mass concentrations of total particulate PAHs were ranked as follows: summer (1.27 ng m^-3) < spring (4.83 ng m^-3) < autumn (6.16 ng m^-3) < winter (18.5 ng m^-3). Clear seasonal differences in PAH concentrations can be explained by direct impact of local and regional urban/industrial activities, with priority winter contribution of coal combustion in residential and commercial sectors. In addition, for summer measurements the diagnostic ratios indicated that high molecular weight PAHs were mainly derived from vehicle emission and petrochemical industry, while relatively low mass contribution of 4-ring congeners to the total sum of PAHs was attributed to photochemical processing. The analysis of meteorological parameters (temperature, relative humidity) and gaseous precursors (SO₂, NO₂, NO_x, O₃ and CO) exhibits their statistically significant correlations with PAHs, indicating local/regional primary emission. The incremental lifetime cancer risk was 1.23 × 10^-5, suggesting potential toxicity and carcinogenicity for adult females and males. This study highlights the importance of the implementation of health risk assessment model in urbanized coastal zones.

Health risk assessment of polycyclic aromatic hydrocarbons in individuals living near restaurants: a cross-sectional study in Shiraz, Iran

Polycyclic aromatic hydrocarbons (PAHs) are persistent toxic substances that have ubiquitous presence in water, air, soil, and sediment environments, posing serious environmental risks. The present study aimed to investigate the concentrations of urinary PAHs and their health effects in individuals living near restaurants via a health risk assessment analysis. This cross-sectional study was performed on 57 people living near restaurants and 30 individuals as the control group. Five urinary metabolites of PAHs were monitored. In order to evaluate the effects of the urinary metabolites of PAHs on Malondialdehyde (MDA) concentration, Total Anti-oxidation Capacity (TAC) in urine samples, and C-Reactive Protein (CRP) in serum samples, regression model was used by considering the effects of the possible confounding factors. Non-carcinogenic health risk was calculated, as well. The median concentration of urinary PAHs was 1196.70 and 627.54 ng/g creatinine in the people living near restaurants and the control group, respectively. Among the metabolites, the lowest and highest mean concentrations were related to 9-OHPhe and 1-OHP, respectively in the two study groups. Moreover, PAHs were significantly associated with MDA level and TAC (p < 0.05). Hazard Quotient (HQ) and Hazard Index (HI) were less than 1. Long-term studies are required to determine the actual health effects by identifying the sources of PAHs emission and to find ways to decrease the production of these compounds.

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 (PM_2.5) 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 PM_2.5 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 PM_2.5 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.

Modeling of the air temperature using the Extreme Value Theory for selected biomes in Mato Grosso do Sul (Brazil)

This paper aims to find probabilities of extreme values of the air temperature for the Cerrado, Pantanal and Atlantic Forest biomes in Mato Grosso do Sul in Brazil. In this case a maximum likelihood estimation was employed for the probability distributions fitting the extreme monthly air temperatures for 2007-2018. Using the Extreme Value Theory approach this work estimates three probability distributions: the Generalized Distribution of Extreme Values (GEV), the Gumbel (GUM) and the Log-Normal (LN). The Kolmogorov-Smirnov test, the corrected Akaike criterion AIC c , the Bayesian information criterion BIC, the root of the mean square error RMSE and the determination coefficient R 2 were applied to measure the goodness-of-fit. The estimated distributions were used to calculate the probabilities of occurrence of maximum monthly air temperatures over 28-32 °C. Temperature predictions were done for the 2-, 5-, 10-, 30-, 50- and 100-year return periods. The GEV and GUM distributions are recommended to be used in the warmer months. In the coldest months, the LN distribution gave a better fit to a series of extreme air temperatures. Deforestation, combustion and extensive fires, and the related aerosol emissions contribute, alongside climate change, to the generation of extreme air temperatures in the studied biomes.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00477-022-02206-1.

Black carbon-climate interactions regulate dust burdens over India revealed during COVID-19

India as a hotspot for air pollution has heavy black carbon (BC) and dust (DU) loadings. BC has been identified to significantly impact the Indian climate. However, whether BC-climate interactions regulate Indian DU during the premonsoon season is unclear. Here, using long-term Reanalysis data, we show that Indian DU is positively correlated to northern Indian BC while negatively correlated to southern Indian BC. We further identify the mechanism of BC-dust-climate interactions revealed during COVID-19. BC reduction in northern India due to lockdown decreases solar heating in the atmosphere and increases surface albedo of the Tibetan Plateau (TP), inducing a descending atmospheric motion. Colder air from the TP together with warmer southern Indian air heated by biomass burning BC results in easterly wind anomalies, which reduces dust transport from the Middle East and Sahara and local dust emissions. The premonsoon aerosol-climate interactions delay the outbreak of the subsequent Indian summer monsoon.

Black carbon produced by human activities impacts climate. Here, the authors find that black carbon-climate interactions regulate Indian dust during the premonsoon season and further affect the outbreak of the subsequent Indian summer monsoon.

Carcinogenic Risk Assessment among Children and Adult due to Exposure to Toxic Air Pollutants

Health endpoint and risk of carcinogenic among people enhancement due to Exposures to toxic air pollutants. The purpose of this study was investigation of a carcinogenic risk assessment among children and adults due to exposure to toxic pollutants. A review study of literature was performed with seven hundred and twenty-six articles were retrieved based on Google Scholar, Web of Science, PubMed, Elsevier, and Springer databases. Studies reporting data on predetermined consequences potential toxic air pollutants and related to lifetime cancer risk (LCR) and hazard quotient (HQ) were used to assess carcinogenic and non-carcinogenic risk. The literature signs a notable undesirable affect from potential toxic air pollutants related to carcinogenic risk assessment among children and adult. Based on Result this study, the toxic air pollutants can endanger health of children and adult exposure to this pollutant and increase lifetime cancer risk number and carcinogenic risk among exposed people. Useful for health policymaker in order to cope with the incidence of cancer among citizenship Can be the main application the results of this study. Increasing the level of public awareness, especially of sensitive groups, about the incidence of cancer and its important factors and reduce exposures to toxic air pollutants are the main vital government actions for decrease the prevalence of cancer. Further research using more sophisticated methodology is warranted.

Characteristics of equivalent black carbon aerosols over Doon Valley in NW Indian Himalaya during COVID-19 lockdown 2020

Recently, black carbon (BC) has been identified as a potential transmitter for COVID-19 besides being responsible for climate change and serious health hazards. To mitigate the dreaded consequences of COVID-19 pandemic, the Government of India declared a nationwide lockdown on March 24, 2020. Accordingly, observations on equivalent black carbon (EBC) aerosols using AE 51 Aethalometer were performed during different lockdowns in Doon Valley. During April, May, June, and July, the monthly average EBC mass concentration recorded 2.12 ± 1.14 μg m^-3, 2.58 ± 1.46 μg m^-3, 2.74 ± 1.49 μg m^-3, and 2.12 ± 1.32 μg m^-3, respectively. A comparison of diurnal variation patterns with earlier studies indicates a significant reduction in EBC mass concentration levels. Bipolar NWR analysis for April and May depicts that relatively high EBC concentration was experienced with prominent south-easterly winds. The EBC concentration level during daytime was high compared to nighttime hours. Preliminary visualization of scanning electron micrographs indicates the variable morphology of aerosols. The bulk particle EDX spectral analysis indicates C, O, Na, F, Al, Si, K, Ca, and Ti elements with a dominance of C and O. Windblown dust seems to be the major contributor to the ambient aerosols. Furthermore, MODIS recorded the fire anomaly (attributed to the wheat stubble burning) starting from mid of April to early-June along the Indo-Gangetic Basin. Heavy loading of polluted aerosols was visible in CALIPSO data imageries. HYSPLIT cluster trajectories indicate that the study region is strongly influenced by the air mass transporting from the Gangetic Plain, Iran, Pakistan, Afghanistan, and Gulf region.

Concentrations, seasonal trends, sources, health risk and subchronic toxicity to the respiratory and immune system of PAHs in PM2.5 in Xi'an

PM_2.5-bound polycyclic aromatic hydrocarbons (PAHs) have been proved to be hazardous to health. Previous studies have focused on the distribution and sources of PAHs, whereas there is little knowledge of the damage to organs. Here we sought to investigate the pollution level and seasonal variation characteristics of PAHs in PM_2.5 in Xi'an and assess the health risk, to establish a PAHs exposure model, and investigate the toxicological effects of PAHs on the respiratory and immune functions. A sub-chronic exposure model of PAHs was established by inhalation. The pathological changes of lung tissues were observed with a light microscope. Inflammatory reactions in alveolar lavage fluid were determined using the corresponding kit. The levels of interleukin-6 (IL-6) and interleukin-8 (IL-8) were detected with enzyme linked immunosorbent assay (ELISA) kit; the proliferation of lymphocytes in spleen was detected with methyl tetrazolium (MTT); DNA immune damage was determined with DNA gel electrophoresis. The results showed that (1) the total concentration of 16 PAHs ranged from 41.1 to 387 ng/m³, with a mean value of 170 ng/m³, and the concentration of PAHs in PM_2.5 was higher in winter than in other seasons. (2) The sources of PAHs in the atmosphere of Xi'an urban area were mainly coal combustion, and the equivalent carcinogenic concentration of PAHs in PM_2.5 was 3.9 ng/m³. (3) Foreign body granuloma formation and inflammatory cell damage were observed in the lungs of rats infected with toxin; the levels of reactive oxygen species (ROS) and mobile device assistant (MDA) increased while nitric oxide synthase (NOS) decreased with the increase of dose; the expression levels of IL-6 and IL-8 elevated with the increase of toxin dose, showing an obvious dose-effect relationship; the level of PAHs damage to cells showed a dose-effect relationship. Sub-chronic exposure to PAHs could cause sustained inflammatory injury to the organism. Measures should be taken to counter the problems of PAHs in PM_2.5 in Xi'an and relevant health promotion strategies should be developed.

Declining carbon emission/concentration during COVID-19: A critical review on temporary relief

In December 2019 the deadly pandemic COVID-19 traumatized mankind through its lethal impact. To seize the outbreak, nationwide/region-based lockdown strategies were adopted by most of the COVID-19 affected countries. This in turn resulted in restricted transportation via surface, water, and air, as well as significantly reduced working hours of the industry sectors, so on and so forth. The obvious outcome was a sudden discernible decline in atmospheric adulteration. Accordingly, the anthropogenic emissions at the global and regional/local scales were examined during the lockdown period by several researchers using both or either satellite-based and ground-based monitoring. Among several other air-contaminants, carbon has a dominant toxicological profile causing adverse health effects and thereby attracting researches interest in carbon-release probing during the systematic confinement period imposed by the ruling authorities across the globe. The results of those studies indicated a confirmed decline in carbon emission/concentration making the air more breathable for the period. In this review, the studies related to anthropogenic emissions of carbon during the lockdown period are accounted for by compiling the recently reported data from published articles.

Impact of biomass induced black carbon particles in cascading COVID-19

We explore the association of biomass-induced black carbon aerosolized virus with COVID-19 in one of the top-ranked polluted hot spot regions of the world, Delhi, at the time when other confounding factors were almost stable and the pandemic wave was on the declining stage. Delhi was worst affected by COVID-19. However, when it was fast returning back to normal after about 6 months with minimum fatalities, it suddenly encountered a reversal with a 10 fold increase in infection counts, coinciding with the onset of the stubble burning period in neighbouring states. We hereby report that the crop residue burning induced lethal aged Black carbon-rich particles which engulfs Delhi during the post-monsoon months of October-November are strongly associated with COVID-19 and largely responsible for the sudden surge. It is found that the virus efficacy is not necessarily related to any particulates but it is more of source-based toxicity of its component where the virus is piggybacking. We conclude that the aged biomass BC particles tend to aggregate and react with other compounds to grow in size, providing temporary habitat to viruses leading to the rapid increase in COVID-19 cases which declined after the crop burning stopped.