PM2.5 and PM>2.5 were separately collected in Kanazawa, Japan in every season from the spring of 2017 to the winter of 2018, and nine polycyclic aromatic hydrocarbons (PAHs) and six nitropolycyclic aromatic hydrocarbons (NPAHs) were determined by HPLC with fluorescence and chemiluminescence detections, respectively. Atmospheric concentrations of both PAHs and NPAHs showed seasonal changes (highest in the winter and lowest in the summer), which were different from the variations of TSP and PM2.5 (highest in the spring). Contributions of major sources to combustion-derived particulate (Pc) in PM2.5 were calculated by the NP-method using pyrene and 1-nitropyrene as representative markers of PAHs and NPAHs, respectively. The annual average concentration of Pc accounted for only 2.1% of PM2.5, but showed the same seasonal variation as PAHs. The sources of Pc were automobiles (31%) and coal heating facilities/industries (69%). The source of Pyr was almost entirely coal heating facilities/industries (98%). A backward trajectory analysis showed that automobile-derived Pc was mainly from Kanazawa and its surroundings and that coal heating facilities-derived Pc was transported from city areas in central and northern China in the winter and during the Asian dust event in the spring. These results show that large amounts of PAHs were long-range transported from China in the winter. Even in spring when the coal heating season was over in China, PAHs came over to Japan after Asian dust storms passed through Chinese city areas. The main contributor of NPAHs was automobiles in Kanazawa and its surroundings. The recent Pc concentrations were much lower than those in 1999. This decrease was mostly attributed to the decrease in the contribution of automobiles. Thus, changes of atmospheric concentrations of Pc, PAHs and NPAHs in Kanazawa were strongly affected not only by the local emissions but also long-range transport from China.

One hundred and twenty (120) fingerlings of Clarias gariepinus (mean weight: 0.96 ± 0.1g) were randomly exposed to 4 experimental treatments of petroleum, based on LC₅₀ values (6.4mg/L of crude oil, 8.7mg/L of petrol, 8.0mg/L of kerosene and 7.8mg/L of diesel oil) and replicated thrice, to determine polycyclic aromatic hydrocarbons (PAH) in exposed fish for 96 h. There was no significant difference (P > 0.05) in total (PAHs) between crude oil (97.1 ng/uL) and diesel (97.2 ng/uL) exposed fish and also between petrol (53.2 ng/uL) and kerosene (49.6 ng/uL) exposed fish, but there was a significant difference (P < 0.05) in PAH levels of the crude oil/diesel exposed -groups of fish compared to petrol/kerosene exposed -groups of fish (97.1/97.2 and 53.2/49.6 ng/uL). Naphthalene correlated positively to benzo a anthracene (r=0.672, (P < 0.05), benzo b fluoranthene (r=0.681, P < 0.05) and chrysene (r=0.615, P < 0.05) but did not correlate to fluorene. Benzo a anthracene correlated positively to benzo a pyrene (r=0.578, P < 0.05), phenathrene (r=0.685, P < 0.05) but did not correlate to acenaphthene. Fluorene correlated positively to benzo a pyrene (r=0.695, P < 0.05) but did not correlate to chrysene. Chrysene correlated positively to dibenzo a,h, pyrene (r=0.658, P < 0.05) to phenathrene and benzo b fluoranthene (r=0.659, P< 0.05). Indeno 123 cd- pyrene and fluranthene however did not correlate to other PAHs except naphthanene, acenaphthene and acenaphthylene. The level of PAH in fish may translate to the toxicity effect since crude oil and diesel with lower LC₅₀ (6.4 and 7.8 mg/L) deposited greater PAH than kerosene and petrol with higher LC₅₀ (8.7 and 8.0 mg/L) in fingerlings of C. gariepinus. High risk to cancer disorders may occur in exposed fish to petroleum with high incidence of fluorene , anthracene, pyrene and benz a anthracene which correlated positively to benzo a pyrene which provide some basis for predicting impact of oil spills on fingerling population.

Background and objectives: The impact of prenatal exposure to polycyclicaromatic 17 hydrocarbons (PAHs) on birth outcomes as weight, length, head circumference, placenta 18 weight, and Apgar. Materials and Methods: Two cohorts of children born in the years 2013 and 19 2014 in Karvina (Northern Moravia, N=144) and Ceske Budejovice (Southern Bohemia, 20 N=198), were studied for the relationship between the prenatal exposure to PAHs and growth 21 parameters up to two years of age. PAHs exposure was evaluated according to the concentration 22 of benzo[a]pyrene (B[a]P) in polluted air and monohydroxylated PAH metabolites (OH-PAHs) 23 in urine of newborns as well as their mothers. Data of growth parameters were obtained from 24 pediatric questionnaires up to 24 months. 25 Results: Concentrations of B[a]P were significantly higher in Karvina (p<0.001). OH-26 PAH metabolites were significantly higher in the mothers´ as well as in the newborns´ urine in 27 Karvina. The length was shorter in newborns in Karvina at birth (p<0.001), but this difference 28 was straightened out during next 3 to 24 months. Birth weight at the delivery did not differ 29 between newborns in Karvina and Ceske Budejovice. Newborns in both locations significantly 30 decreased their weight gain between birth and 3 months after delivery. OH-PAHs metabolites 31 in mother’s or newborn’s urine did not affect birth weight. Top 25% values of concentrations 32 of 2-OH-FLUO, 1-OH-NAP, 2-OH-NAP, 1-OH-PHEN, 2-OH-PHEN, 3-OH-PHEN, 4-OH-33 PHEN, and the sum of all-OH-PAHs higher than median in the newborns´ urine decreased their 34 length. 2-OH-PHEN top 25% of concentrations in the newborns´ urine decreased their head 35 circumference, 2-OH-FLUO, 1-OH-NAP, 2-OH-NAP, 1-OH-PHEN, 2-OH-PHEN, 3-OH-36 PHEN, 4-OH-PHEN, 9-OH-PHEN, 1-OH-PYR, and all-OH-PAHs decreased placenta weight; 37 2-OH-FLUO, 1-OH-NAP, 2-OH-NAP, 1-OH-PHEN, 2-OH-PHEN, 3-OH-PHEN, 4-OH-38 PHEN, and all-OH-PAHs decreased Apgar 5´. Conclusions: We observed that higher 39 concentration of PAHs determined as OH-PAHs metabolites in newborns´ urine decreased their 40 length, head circumference, placenta weight, and Apgar 5´, but did not affect birth weight.

There is a sustained rise in incidence of cancer and toxicity related to chemicals exerting enormous burden to public health and biodiversity. Polycyclic Aromatic Hydrocarbons (PAHs) are mong such contaminants, precisely the sixteen-priority characterized by United States Environmental Protection Agency (USEPA). Therefore, this review is aimed at further elaboration about the 16 USEPA characterized PAHs and threat portend to public health and biodiversity. PAHs are a class of very stable organic pollutants produced most commonly, by incomplete combustion of fossil fuel and are formed when complex organic substances are exposed to heat. PAHs in great amount due to build up over time by bioaccumulation can be perilous: to human beings of all age and levels, aquatic organisms, amphibians and reptiles. The soil like the aquatic environment contains substantial quantity of PAHs since, atmospheric PAHs sediments on the soil due to dry and wet deposition, terrestrial organism are impacted if the soil is saturated with PAHs. Therefore, PAHs are a great source of trepidation for food safety, public health and biodiversity sustenance. Hence, tackling the spade of the menacing ubiquity of PAHs becomes necessary from its sources by encouragement of alternatives to petroleum fuels for machines and vehicles.

Residential dust is recognized as a major source of environmental contaminants, including polycyclic aromatic hydrocarbons (PAHs) and phthalic acid esters (PAEs). To characterize the thoracic dust fraction (PM10), a sampling campaign was carried out with an in-situ resuspension chamber in three rooms (kitchen, living room and bedroom) of four Spanish houses. Two samples per room were collected with, at least, a one-week interval. The PM₁₀ samples were analyzed for their carbonaceous content by a thermo-optical technique and, after solvent extraction, for 20 PAHs, 8 phthalate plasticizers (PAEs) and one non-phthalate plasticizer (DEHA) by gas chromatography-mass spectrometry. In general, higher dust loads were observed for parquet flooring compared with tile. The highest dust loads were obtained for rugs. Total carbon accounted for 9.3 to 51%wt of the PM₁₀ mass. Plasticizer mass fractions varied from 5 µg g-1 to 17 mg g^-1 PM₁₀, whereas lower contributions were registered for PAHs (0.98–116 µg g^-1). The plasticizer and PAH daily intakes for children and adults via dust ingestion were estimated to be 3–4 orders of magnitude higher than those via inhalation and dermal contact. Potential carcinogenic and negligible non-carcinogenic risks arising from exposure to PAHs were found.

In September 2021, the European Chemicals Agency evaluated a dossier for restricting polycyclic aromatic hydrocarbons (PAHs) in infant diapers and concluded that risks were not demonstrat-ed because of inconclusive exposure data. To fill this gap, we measured the 16 priority PAHs of the U.S. Environmental Protection Agency in the diaper core of four brands and in the sheets and fastening tapes of six brands of commercially available diapers. Health risks were conservatively assessed by assuming that dermally absorbed PAHs can cause both local (skin cancer) and sys-temic critical effects (neurobehavioral changes). Total concentrations of PAHs in diaper core and top sheet, the only significant contributors to skin exposure, averaged 34.5 μg/kg and 66.8 μg/kg, respectively. Excess skin cancer risks and hazard quotients for neurobehavioral effects calculated with the daily dose of total PAHs from combined diaper core and top sheet averaged 1.4 x 10-7 and 1.19 x 10-2, respectively. The median daily dose of total PAHs and of its ben-zo[a]pyrene-equivalent from breast milk estimated worldwide are 171 and 30 times greater than that from combined diaper core and top sheet, respectively. Altogether these findings indicate that trace levels of PAHs found in infant diapers are unlikely to pose health risks.

With increasing interest in understanding contribution of secondary organic aerosol (SOA) to particulate air pollution in urban areas, an exploratory study was carried out to determine levels of carbonaceous aerosols and polycyclic aromatic hydrocarbons (PAHs) in the City of Kuala Lumpur, Malaysia. PM2.5 samples were collected using a high-volume sampler for 24 h in several areas in Kuala Lumpur during the north-easterly monsoon from January to March 2019. Samples were analysed for water soluble organic carbon (WSOC), organic carbon (OC), elemental carbon (EC) and secondary organic carbon (SOC) in PM2.5 was estimated. Particle-bound PAHs were analysed using gas chromatography-flame ionization detector (GC-FID). Average concentrations of WSOC, OC and EC were 2.7 ± 2.2 (range of 0.63-9.1) µg/m3, 6.9 ± 4.9 (3.1-24.1) µg/m3 and 3.7 ± 1.6 (1.3-6.8) µg/m3, respectively, with estimated average SOC of 2.3 µg/m3, contributing 34% to total OC. The average of total PAHs was 1.8 ± 2.7 ng/m3. Source identification methods revealed natural gas and biomass burning, and urban traffic combustion as dominant sources of PAHs in Kuala Lumpur. To understand human health risk posed by PAHs, a deterministic screening health risk assessment was also conducted for several age groups including infant, toddler, children, adolescent and adult. The total concentration of BaPeq is 3.8 ng/m3, with the average of 0.29 (range of 0.001-1.6) ng/m3. Carcinogenic and non-carcinogenic risk of PAH species were well below the acceptable levels recommended by the USEPA. Future work is needed using long-term monitoring data to understand the origin of PAH contributing to SOA formation and to apply source-risk apportionment to know better the potential risk factors posed by the various sources in urban areas in Kuala Lumpur.

Fabric phase sorptive extraction (FPSE) combines the advanced material properties of sol–gel derived microextraction sorbents and the flexible and permeable fabric support to create a robust, simple and green sample preparation device. It simultaneously improves the extraction sensitivity, and the speed of the extraction by incorporating high volume of sponge-like porous sol–gel hybrid inorganic–organic sorbents into permeable fabric substrates that is capable of extracting target analytes directly from simple to complex aqueous sample matrices. For the first time, this technique was applied to the trace level determination of selected polycyclic aromatic hydrocarbons (PAHs) in environmental water samples using a non-polar sol–gel C18 coated FPSE media. Several extraction parameters were optimized to improve extraction efficiency and to achieve high detection sensitivity. Validation tests of spiked samples showed good linearity for four selected PAHs (R² = 0.9983–0.9997) over a wide range of concentrations (0.010-10 ng/mL). Limits of detection (LODs) and quantification (LOQs) were measured at pg/mL levels, 0.1–1 pg/mL and 0.3–3 pg/mL, respectively. Inter- and intra-day precision tests showed variations of 1.1–4.1% for four selected PAHs. Average absolute recovery values were in the range of 88.1–90.5% surpassed the recovery prediction model, with relative standard deviations below 5%. The developed FPSE-HPLC-FLD protocol was finally applied to analyze 8 environmental water samples. Out of four selected PAHs, fluoranthene (Flu) and phenanthrene (Phen) were the most frequently detected in four samples, at concentration levels of 5.6–7.7 ng/mL and 4.1-11 ng/mL, respectively followed by anthracene (Anth) and pyrene (Pyr) in two samples. The newly developed FPSE-HPLC-FLD protocol is simple, green, fast and economical, with adequate sensitivity for trace levels of four selected PAHs and seems to be promising in routine monitoring of water quality and safety.

Phytoremediation, a method of phytomanagement using the plant holobiont to clean up polluted soils, is particularly effective for degrading organic pollutants, such as alkanes and polycyclic aromatic hydrocarbons (PAHS). However, the respective contributions of host plants and their associated microbiota within the holobiont to the efficiency of phytoremediation is poorly understood. Identification of plant-associated bacteria capable of efficiently utilizing these compounds as carbon source while stimulating plant-growth, is a keystone for phytomanagement engineering in order to improve the efficiency of pollutant removal. In this study, we sampled the rhizosphere and the surrounding bulk soil of Salix purpurea and Eleocharis obusta from the site of a former petrochemical plant in Varennes, QC, Canada. Our objectives were to: (i) isolate and identify indigenous bacteria inhabiting these biotopes; (ii) assess the ability of isolated bacteria to utilize alkanes (dodecane and hexadecane) and PAHs (naphthalene, phenanthrene and pyrene) as the sole carbon source, and (iii) determine the plant growth-promoting (PGP) potential of the isolates using five key traits. A total of 438 morphologically different bacterial isolates were obtained, purified, preserved and identified through PCR and 16S rRNA gene sequencing. Identified isolates represent 62 genera, including taxa such as Acinetobacter, Arthrobacter, Bacillus, Enterobacter, Nocardia, Pseudomonas, Rhodococcus, Streptomyces and Variovorax. Approximately, 32% of bacterial isolates, including Arthrobacter, Pseudomonas, Streptomyces, Enterobacter, Nocardia, Acinetobacter and Microbacterium, were able to utilize all five different hydrocarbons compounds. Additionally, 5% of tested isolates belonging to genera Pseudomonas, Acinetobacter, Serratia, Klebsiella, Microbacterium, Bacillus and Stenotrophomonas possessed all five of the tested PGP functional traits. This culture collection of diverse, petroleum-hydrocarbon degrading bacteria, with multiple PGP traits, represents a valuable resource for future use in environmental bio- and phyto-technology applications, including phytoremediation of petroleum hydrocarbons contaminated soils and phytomanagement of anthropized areas.

This review documents an emerging body of evidence concerning the neurological effect of polycyclic aromatic hydrocarbon (PAH) exposure, with regard to cognitive function and increased risk of neurodegeneration. Two electronic databases PubMed and Web of Science were systematically searched. The 37/428 studies selected included outcomes measuring cognitive function, neurobehavioral symptoms of impaired cognition, and pathologies associated with neurodegeneration from prenatal (21/37 studies), childhood (14/37 studies), and adult (8/37 studies) PAH exposure. Sufficient evidence surrounding prenatal exposure negatively impacting child intelligence, mental development, average overall development, verbal IQ, memory impairment, externalizing, internalizing, anxious, depressed behaviours, behavioural development and child attentiveness was found. Evidence concerning exposure during childhood and as an adult was scarce and highly heterogeneous, however presence of neurodegenerative biomarkers and increased concentrations of cryptic “self” antigens in serum and cerebrospinal fluid samples suggest a higher risk of neurodegenerative disease. Associations with lowered cognitive ability, and impaired attentiveness were found in children and memory disturbances, specifically auditory memory, verbal learning and general memory in adults. Although evidence is not yet conclusive and further research is needed the studies included supported the hypothesis that PAH exposure negatively impacts cognitive function and increases the risk of neurodegeneration in humans, and recommends considering the introduction of a variable “rural vs. urban” as covariate for adjusting analyses where the neurological functions affected (as result of our review) are outcome variables.

New fluorinated pentaphene derivative has been obtained as a potential precursor for fluorinated polycyclic aromatic hydrocarbons. In this work 7,7-difluoropentaphen-6(7H)-one was prepared from 1,1-difluoroanthracen-2(1H)-one via Diels-Alder reaction with o-quinodimethane generated in situ from o-bis(dibromomethyl)benzene. The structure of newly synthesized compound was confirmed by 1H, 13C, 19F NMR, IR and UV/Vis spectroscopy as well as high-resolution mass spectrometry.

In January 2019, the French Agency for Food, Environmental and Occupational Health and Safety (ANSES) published an opinion on risks related to the presence of hazardous chemicals in infant diapers. ANSES found that health reference values were largely exceeded for polycyclic aromatic hydrocarbons (PAHs), dioxins (PCCD/Fs) and dioxin-like polychlorobiphenyls (DL-PCBs). The levels of formaldehyde and of some fragrances were also considered potentially unsafe. Therefore, ANSES concluded that actions have to be taken to restrict levels of these contaminants in diapers. Under the exposure scenario deemed the most reliable by ANSES, estimates of cancer risks of the most potent PAHs detected in diapers exceeded 10-3 and hazard quotients for neurobehavioral effects attained values up to 66. Regarding dioxins and DL-PCBs, ANSES derived a hazard quotient of 12 for the risk of decreased sperm count at adult age. The aim of this critical review was to examine whether the exposure and risk assessment conducted by ANSES contained potential flaws that could explain such a high exceedance of health reference values. The review will also put into perspective the exposure from diapers with that from breast milk whose benefits for child’s health are undisputable despite contamination by PAHs, dioxins and DL-PCBS.

Research subjects of this study are four representative locations in the industrial complex, in the city of Banja Luka, Republic of Srpska, Bosnia and Herzegovina. 16 polycyclic aromatic hydrocarbons (PAHs) (∑16PAHs), humus and pH were determined. The main objective of the paper is to determine the concentration levels, to assess the probable sources of PAHs contamination in soil and groundwater and to determine the ecological risk. The ∑16PAHs in soil (at depths of 30 cm, 100 cm, 200 cm, 300 cm and 400 cm) ranged from 0.99 to 2.24 mg/kg, from 0.34 to 0.46, from 0.24 to 0.32, from 0.13 to 0.27 and from 0.13 to 0.47, with mean values of 1.70 mg/kg, 0.40 mg/kg, 0.28 mg/kg, 0.20 mg/kg and 0.26 mg/kg, respectively. The ∑16PAHs in groundwater ranged from 0.23 to 4.50 mg/m³, with a mean value of 1.42 mg/m³. Surface soil and groundwater are heavily contaminated. All values of ∑PAHs in soil layers were lower in the depths of the soil. Factor analysis indicates three sources of contamination, i.e. principal component (PC) PC1 (pyrogenic), PC2 (petrogenic) and PC3 (biomass), with 52.39%, 26.14% and 8.46% of the total variance, respectively. ∑PAH and PAHs indicate high ecological risk for most PAHs, which decreases with soil depth.

The current research investigated the environmental risk of the polycyclic musk compounds, Galaxolide® (HHCB) and Tonalide® (AHTN), in the marine environments. These substances are lipophilic, bioaccumulated and potentially biomagnified in aquatic organisms. To understand the toxicity of HHCB and AHTN, we performed acute toxicity tests by exposing marine microalgae (Phaeodactylum tricornutum, Tretraselmis chuii and Isochrysis galbana), crustaceans (Artemia franciscana), echinoderms (Paracentrotus lividus), bivalves (Mytilus galloprovincialis), fish (Sparus aurata) and a candidate freshwater microalga (Raphidocelis subcapitata) to environmentally relevant concentrations (0.005 - 5 µg/L) following standardized protocols. The effects of both substances on microalgae growth were incipient and only I. galbana was sensitive to HHCB and AHTN, with IC10 values of 5.22 µg/L and 0.328 µg/L, respectively. Significant (p < 0.01) concentration dependent responses were measured in P. lividus and M. galloprovincialis larvae developments as well as S. aurata mortality tested with HHCB. The effect of HHCB on P. lividus larvae development was the most sensitive endpoint recorded, producing an EC50 value of 4.07 µg/L. Our results show that HHCB represents a high risk to P. lividus larvae development for early life stages in marine environments.

In this study, the use of recycled diatomaceous earth as the extraction phase in a the solid phase microextraction (SPME) technique for the determination of polycyclic aromatic hydrocarbons (PAHs) in river water samples, with separation/detection performed by gas chromatography-mass spectrometry (GC-MS), is proposed. The optimized extraction conditions are extraction time 70 min at 80 ºC with no addition of salt. The limits of quantification were close to 0.5 μg L-1 with RSD values lower than 25% (n = 3). The linear working range was 0.5 μg L-1 to 25 μg L-1 for all analytes. The method was applied to samples collected from the Itajaí River (Santa Catarina, Brazil) and the RSD values for repeatability and reproducibility were lower than 15% and 17%, respectively. The efficiency of the recycled diatomaceous earth fiber was compared with that of commercial fibers and good results were obtained, confirming that this is a promising option for use as the extraction phase in SPME.

Soil contamination with petroleum hydrocarbons (PHCs) has become a global concern in the word due to intensification of industrial activities. This creates a serious environmental issue, therefore there is a need to find solutions, including application of efficient remediation technologies, or to improve current techniques. Rhizoremediation is a sub-category of the phytoremediation which refers to Phytomanagement that uses plants and their associated microbiota. These green technologies have received a global attention as a cost-effective and possible efficient remediation technique that can be applied to cleanup PHCs-polluted soils. The mechanism of rhizoremediation process is that plant roots stimulate soil microbes to mineralize organic contaminants to H2O and CO2. However, this multipartite interaction is much complex because many biotic and abiotic factors can influence microbial processes in the soil, making the efficiency of rhizoremediation unpredictable. This review reports the progress made on rhizoremediation approaches that can overcome the limitations and improve the efficiency of PHCs-contaminated soils. The addressed approaches in this review include: 1) selecting plants with desired characteristics suitable for rhizoremediation, 2) the exploitation and manipulation of plant microbiome by using inoculant containing plant growth-promoting rhizobacteria (PGPR) or hydrocarbon-degrading microbes, or a combination of both types of organisms, and 3) enhancement of the understanding of how host-plant assembles a beneficial microbiome, and how it functions, under pollutant stress.

Studies on the characteristics of hazardous air pollutants (HAPs) in the emissions of medium-duty diesel trucks are significantly insufficient compared to that on heavy-duty trucks. This study investigates the characteristics of regulated pollutants and HAPs such as volatile organic compounds (VOCs), aldehydes, and polycyclic aromatic hydrocarbons (PAHs), and estimates non-methane hydrocarbon (NMHC) speciation in the emissions of medium-duty diesel trucks. Ten medium-duty diesel trucks conforming to Euros 5 and 6 were tested for worldwide harmonized light duty driving test cycle (WLTC), new European driving cycle (NEDC), constant volume sampler (CVS)-75, and National Institute of Environmental Research (NIER)-9 using a chassis dynamometer. CO and NMHC emissions were the highest in the NEDC because of its longer low-speed driving time. NOx emissions were the highest in WLTC owing to the influence of thermal NOx in the high-speed phase. Alkanes dominated non-methane volatile compound (NMVOC) emissions owing to the low reaction of the diesel oxidation catalyst. After-treatment system, driving, and engine conditions influenced the individual components of NMVOC emissions. Formaldehyde emissions were the highest among aldehydes irrespective of driving cycles. By sampling the particle-phase of PAHs, we detected benzo(k)fluoranthene and benzo(a)pyrene and estimated the concentrations of the gas-phase PAHs with models to obtain the total PAH concentrations. The toxic equivalency quantities of benzo(k)fluoranthene and benzo(a)pyrene from NIER-9 (cold) for both Euro 5 and Euro 6 vehicles were more than five times higher than that of NIER (hot) and NEDC. In the case of NMHC speciation, formaldehyde emissions were the highest in all the driving cycles. Formaldehyde and benzene must be controlled in the emissions of medium-duty diesel trucks to reduce their health threats. The results of this study will aid in establishing a national emission inventory system for HAPs of mobile sources in Korea.

Polyaromatic hydrocarbons (PAHs) are widespread in the interstellar medium (ISM). The abundance and relevance of PAHs call for a clear understanding of their formation mechanisms, which, to date, have not been completely deciphered. Of particular interest is the formation of benzene, the basic building block of PAHs. It has been shown that ionization of neutral clusters can lead to an intra-cluster ionic polymerization process that results in molecular growth. Ab initio molecular dynamics (AIMD) studies in clusters consisting of 3–6 units of acetylene modeling ionization events under ISM conditions have shown maximum aggregation of three acetylene molecules forming bonded C6H6+ species: the larger the number of acetylene molecules, the higher the production of C6H6+. These results lead to the question of whether clusters bigger than those studied thus far promote aggregation beyond three acetylene units, and whether larger clusters can result in higher C6H6+ production. In this study, we report results from AIMD simulations modeling the ionization of 10 and 20 acetylene clusters. The simulations show aggregation of up to four acetylene units producing bonded C8H8+. Interestingly, C8H8+ bicyclic species were identified, setting precedent for their astrochemical identification. Comparable reactivity rates were shown with 10 and 20 acetylene clusters.