Total Volatile Organic Compounds Concentrations Research Articles

Unlocking Urban Insights: A Case Study on Impact of Urban Vegetation on Volatile Organic Compounds (VOCs) Variability Across Different Areas of Reggio Emilia, Italy

The Po Valley is one of the European regions most severely affected by air pollution. Within the spectrum of airborne molecules, Volatile Organic Compounds (VOCs) represent a significant component, derived from both natural processes and anthropogenic sources. All VOCs influence air quality, as they are precursors to ozone (O3), secondary organic aerosol (SOA), and particulate matter (PM). While naturally occurring VOCs contribute to the formation of air pollutants, they also have beneficial effects on human health. Furthermore, vegetation plays a fundamental role in air purification and improvement of air quality both directly, through the metabolic processes of leaves, and indirectly, through physical mechanisms.
 This study aims to evaluate the qualitative and quantitative fluctuations of VOCs in different zones within the city of Reggio Emilia (Italy), characterized by varying percentages of vegetation cover and proximity to high-traffic roads. The collected data suggest that air quality may be influenced by the spatial distribution and type of urban area, with urban parks and green zones showing lower concentrations of total VOCs compared to areas with less vegetation cover. These observations can contribute to formulating strategies to improve air quality in urban areas and emphasize the importance of vegetation in an urban context.

Process-specific volatile organic compounds emission characteristics, environmental impact and health risk assessments of the petrochemical industry in the Beijing-Tianjin-Hebei region.

Volatile organic compounds (VOCs) concentration, source profiles, O3 and SOA formation, and health risks were investigated in the petrochemical industry in Beijing-Tianjin-Hebei. The results showed that total VOCs concentrations were 547.1-1956.5μg·m-3, and alkanes were the most abundant group in all processes (31.4%-54.6%), followed by alkenes (20.6%-29.2%) and aromatics (10.1%-25.1%). Moreover, ethylene (11.3%), iso-pentane (7.1%), n-hexane (5.1%), benzene (4.9%) and 2,2-dimethylbutae (4.8%) were identified as the top five species released for the whole petrochemical industry. The coefficient of divergence between the source profiles from different processes was 0.49-0.73, indicating that most source profiles must not be similar. Moreover, because of the different raw materials and technologies used, the source profiles in this study are significantly different from those of other regions. The ozone and secondary organic aerosol formation potentials (OFPs and SOAPs) were evaluated, suggesting that ethylene, propylene, 1-butene, m,p-xylene, and 1,3-butadiene should be preferentially controlled to reduce OFPs. That benzene, toluene, ethylbenzene, m,p-xylene, isopropylbenzene, o-ethyltoluene, and 1,3,5-trimethylbenzene should be priority control compounds for SOAPs. Additionally, the total hazard ratio for non-cancer risk ranged from 0.9 to 7.7, and only living area was unlikely to be related to adverse health effects. Cancer risks associated with organic chemicals, rubber synthesis, oil refining, and wastewater collection and treatment have definite risks, whereas other processes have probable risks. This study provides a scientific basis for VOCs emission control and management and guides human health in the petrochemical industry.

Assessment of indoor and outdoor formaldehyde, total volatile organic compounds (TVOC), and particulate matter (PM2.5, and PM10) levels in Kalasin, Thailand

Background This study sought to determine how much formaldehyde, TVOCs (total volatile organic compounds), and particulate matter (PM2.5, and PM10) were present in the air inside and outdoors at seven distinct locations in Kalasin Province. Methods The stations that were chosen comprised roadways of importance, neighborhoods where people live, shopping centers, motorcycle repair shops, gas stations, industrial zones, and rural areas. A gas detector with four sensors was used to measure formaldehyde, PM2.5, TVOC, temperature, and humidity levels. Particulate samplers were used specifically for measuring PM2.5 and PM10 concentrations. The formaldehyde and TVOC sensors were utilized to measure the concentrations of specific air contaminants. Results These stations from important roads, residential neighborhoods, shopping centers, motorcycle repair shops, gas stations, industrial zones, and rural locations had formaldehyde of 0.0207, 0.0239, 0.1892, 0.1893, 0.0273, 0.0262, and 0.0409 mg/m3, respectively. It was discovered that TVOC values ranged from 0.0848 to 0.990 to 0.8466 to 0.1944 to 0.1188 to 0.108 to 0.1708 mg/m3. The measurements for PM 2.5 were 4.7778, 4.2222, 5.0000, 3.4444, 4.7778, 5.7778, and 6.6667 μg/m3 at the roads, residential neighborhoods, shopping centers, motorcycle repair shops, gas stations, industrial zones, and rural locations. The measurements for PM10 were 4.7778, 4.0000, 5.0000, 3.1111, 5.0000, 6.0000, and 8.0000 μg/m3, respectively. According to the research, formaldehyde levels in stores and motorbike maintenance facilities are higher than the Thai Air Standard. The only TVOC concentration that was found to be above the allowable limit was in shopping centers. However, despite the rural area station showing slightly increased levels, all stations met the PM2.5 and PM10 air quality criteria. Conclusions People who breathe polluted air face both short- and long-term health concerns, underscoring the significance of spreading awareness of this problem.

Changes in total volatile organic compound concentration in Seoul subway stations before (2019) and after (2021) the COVID-19 outbreak

Volatile organic compounds (VOCs) are major air pollutants often designated as specific hazardous or toxic. This study analyzed the trends in concentration changes and influencing factors of VOCs in underground subway stations in the Seoul Metro before (2019) and after (2021) the COVID-19 pandemic. A total of 506 samples were collected from 253 stations on lines 1–8 between May 2019 and September 2021. Total VOC concentrations in Seoul Metro increased after the COVID-19 pandemic 3.8 times over. The deeper the underground station platform, the greater the difference in the VOC concentrations between 2019 and 2021, which was positively related. Average VOC concentration was the highest (52.8 µg/m3) at a depth of 25–30 m and the lowest (23.9 µg/m3) at a depth of < 10 m in 2019. In conclusion, excessive disinfection during the COVID-19 pandemic resulted in increased VOC concentrations in the Seoul Metro, especially in the deeper underground stations. Less frequent quarantine disinfection is recommended to improve air quality.

Preliminary Study on the Emission Dynamics of TVOC and Formaldehyde in Homes with Eco-Friendly Materials: Beyond Green Building

This preliminary study investigates the emission characteristics of formaldehyde (HCHO) and total volatile organic compounds (TVOC) in indoor environments, comparing the effects of eco-friendly materials and general materials. The study analyzes the concentration changes over time in the living rooms of experimental units to assess the effectiveness of eco-friendly materials in reducing indoor air pollutants. The results show that eco-friendly materials exhibit lower initial emissions of TVOC than general materials, gradually decreasing over time. Compared to the eco-friendly material unit, the general material unit takes longer to reach acceptable TVOC concentrations. The emission pattern of HCHO differs from TVOC, with the highest peak occurring on the seventh day. Major individual VOCs, except for benzene, exhibit a similar decreasing trend for TVOC over time. Eco-friendly materials demonstrate significant reductions in emissions compared to general materials in various material applications, including parquet flooring, wallpaper, built-in furniture, and kitchen furniture. However, the difference in emissions for door and window frames using eco-friendly materials is minimal. These findings emphasize the effectiveness of eco-friendly materials in reducing indoor air pollutants and provide valuable insights for creating healthier living environments. Further research is needed to optimize the application of eco-friendly materials in specific components and investigate their long-term impact on indoor air quality and occupant health.

Health risks and environmental influence of volatile organic compounds (VOCs) in a residential area near an industrial park in Southeast China

Industry emission is an important source of anthropogenic volatile organic compounds (VOCs) in China, which have caused elevated ground-level ozone (O3) and fine particulate matter (PM2.5) concentrations and potential adverse human health effects. This study investigated compositions, sources, and health risks of ambient VOCs in a residential area near an industrial park in Southeast China. The concentrations of total VOCs in spring and autumn were 16.7 ± 10.2 ppbv and 14.7 ± 8.35 ppbv, respectively. Alkanes and oxygenated VOCs (OVOCs) were the predominant components that contributed to the ozone formation potential (OFP), while the greatest contribution to secondary organic aerosol formation potential (SOAFP) was due to benzene, toluene, ethylbenzene, and xylene (BTEX). Based on the positive matrix factorization model analysis, the relative contributions of individual VOC sources are as follows: industrial process (49.6% and 53.5% in spring and autumn, respectively), vehicle exhausts (26.9% and 33.2%), solvent usage (17.9% and 8.6%), and biogenic source (5.6% and 4.7%). The carcinogenic risk of benzene in autumn and those of 1,2-dibromoethane in both seasons exceeded the acceptable level of 1.00 × 10−6. The hazard index of the observed 21 toxic VOCs was less than 1, suggesting no non-carcinogenic risk at the monitoring site. This study provides valuable information on public health management by taking effective measures to control benzene and halogenated hydrocarbon pollution from industry.

Vertical distribution of VOCs in the boundary layer of the Lhasa valley and its impact on ozone pollution

To investigate the vertical distribution of volatile organic compounds (VOCs) concentrations in the Lhasa valley region, an intensive measurement campaign was first conducted in summer using a tethered balloon. The results showed that the average concentration of surface VOCs was 49.1 ± 30.1 ppbv, alkanes and aromatics were the main components. Notably, a very large discrepancy in VOCs was obtained between the wet (71.6 ± 25.9 ppbv) and dry (25.6 ± 8.0 ppbv) episodes, which was attributed to the atmospheric stability and diffusion capacity. Moreover, the total VOC (TVOCs) concentration declined under fluctuations, but it rapidly increased with height in the afternoon during the wet episode (2.50 ppbv/100 m, R2 = 0.47). According to the PMF results, combustion was the dominant emission source, additionally, the contribution of solvent coating in the wet episode and the background in the dry episode increased with height. Moreover, the O3 concentration increased with height, and the decrease in LNOx-OH could effectively prevent the occurrence of high O3 values. This study indicated that low wind speeds and high humidity levels highly likely cause the accumulation of atmospheric VOCs under static and stable conditions, while the control of high O3 concentrations must still greatly consider summertime NOx emissions in Lhasa.

Indoor environmental conditions of selected shopping malls in Nigeria: A comparative study of microclimatic conditions, noise levels, and microbial burdens

The activities of people and equipment used within shopping malls are major factors that contribute to air pollution and increased sound levels, thereby affecting indoor environmental quality and the well-being of mall operators. This study assessed indoor environmental quality through microbial characterization and measurement of environmental conditions present in selected shopping malls. Investigations were conducted at three shopping malls in Ibadan selected through convenience sampling technique. Environmental parameters such as noise level, relative humidity, temperature, PM2.5 levels, total volatile organic compound (TVOC) levels, microbial characterization, and quantity were determined. Microclimatic parameters (temperature and relative humidity) were measured using a 4-in-1 Precision Gold N09AQ multi-tester. Culturable airborne microbes were collected using the settle plate technique. PM2.5 and TVOC levels were measured using a Thermo Scientific MIE pDR-1500 PM monitor and sf200-TVOC meter respectively. Two bacteria species and five fungi species were isolated across the malls. The noise levels ranged from 61.27 to 81.20 dB. The mean temperatures (highest mean of 33.44 ± 1.42 °C), PM2.5 (highest mean of 114.06 ± 25.64 μg/m3), and TVOC (highest mean of 55.21 ± 8.28 ppm) concentrations were higher than the permissible limits stipulated by the WHO guidelines and NESREA standard limits across all the selected malls. A positive correlation was found to exist between particulate matter and TVOC (r = 0.174, p = 0.004). The total bacteria count was generally high with the highest mean of 1965.33 ± 368.56 CFU/m3, while the total fungi count was generally low with the highest mean of 579.82 ± 51.55 CFU/m3. Bacillus spp. and Candida spp. were found to the consistent from all sample points across the three malls. The bacteria isolated are Gram-positive bacteria associated with human skin which suggests a high rate of indoor pollution from humans. In conclusion, this research has demonstrated the necessity to monitor noise levels and indoor air quality in malls. Also, there is need for government policies to improve indoor air quality which must be enforced and regulated, especially within shopping malls.

Characteristics Analysis of Volatile Organic Compounds Pollution in Residential Buildings in Northeast China Based on Field Measurement

A total of 8 mechanically ventilated residential buildings and 8 naturally ventilated residential buildings were selected to analyze the pollution characteristics of indoor VOCs under different ventilation modes in the severe cold area of northeast China. On typical meteorological days in each season, VOCs were detected on site, and ventilation modes were investigated by long-term online monitoring. The test results showed that the TVOC (total volatile organic compounds) concentrations varied greatly in different seasons or different functional rooms, and the TVOC concentration was the highest in winter, with a value of 0.994 mg/m3. The kitchen was the place with the most serious VOC pollution, and the TVOC concentration could reach 1.403 mg/m3. Benzene series and methylsiloxane had the highest detection rates, but the detected concentrations were low, and the average concentrations were 0.025 mg/m3 and 0.013 mg/m3 respectively. Among the VOC types with a detection rate greater than 50%, the average proportions of aldehydes, alkanes, and benzene series were 18.7%, 15.39%, and 14.38%, respectively. And their mass ratios were also high, which were 14.90%, 30.85%, and 15.70%, respectively. The annual daily average ventilation duration of mechanically ventilated residential buildings was 7.84 h longer than that of naturally ventilated residential buildings. The median TVOC concentrations of mechanically ventilated residential buildings and naturally ventilated residential buildings were 0.621 mg/m3 and 0.707 mg/m3, respectively. The fresh air system was applicable in the severe cold area of northeast China.

Occupational Risks of Podologists: A Combined Assessment of VOCs, Vibration, Noise Levels and Health Complaints

ABSTRACT Podologists are exposed to many occupational hazards, including volatile organic compounds (VOCs) from insole manufacturing and noise/vibration during nail or tissue grinding. In this study, VOCs, noise, and vibration were measured in five podiatry clinics and three offices. Questionnaires were administered to 23 podologists and 19 office workers to inquire about their pain, ocular, skin and respiratory complaints. The results showed that the podologists’ exposure to the total VOC concentrations was approximately twice as high as that of the office workers. The podologists’ complaints regarding pain were found to be correlated with ambient noise and hand-arm vibration levels. Ocular, skin, and respiratory complaints were also found to be correlated with total VOC concentrations. These results suggest that VOCs, noise and vibration in the working environment may impair podologists’ health and that they have an intensifying effect on each other, increasing the severity of health issues.

Volatile organic compounds in school environments of Hawassa city, Ethiopia and assessment of possible human health risks

Volatile organic compounds (VOCs) have become a major human wellbeing and environmental concern worldwide. However, evidence on VOC concentrations in primary school environments in Africa, including Ethiopia, is scarce. The goal of this research was to examine VOCs in primary schools in Hawassa, Ethiopia, and to evaluate possible health threats. Concentrations of 76 VOCs were investigated in air samples from classrooms and playgrounds of eight primary schools in Hawassa, Ethiopia. Air samples were taken via passive sampling method using Tenax TA as a sorbent and analyzed by using thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS). Highest total VOCs (TVOCs) concentration (83 μg/m3) was observed in the classroom of School 2 followed by the classroom of School 1 (76 μg/m3), while the smallest TVOC concentration, 37 μg/m3 in the playground of School 8. Among the BTEX, toluene was the most dominant in all samples, ranging from 33% in School 4–38% in School 1 of ∑BTEX. I/O ratios of individual VOC in the schools ranged from 0.44 in School 4 to 9.21 in School 2. The highest cumulative cancer risk (CCR × 106) and the total hazard ratio indicator (THRI) values were 126 and 1.58E-01 respectively, in the classroom of School 4. The CCR and THRI values indicated that the exposure of children to the measured concentrations of benzene may have potentially harmful effects.

Characterization of photochemical losses of volatile organic compounds and their implications for ozone formation potential and source apportionment during summer in suburban Jinan, China

Volatile organic compounds (VOCs) undergo substantial photochemical losses during their transport from emission sources to receptor sites, resulting in serious implications for their source apportionment and ozone (O3) formation. Based on the continuous measurements of VOCs in suburban Jinan in August 2022, the effects of photochemical losses on VOC source contributions and O3 formation were evaluated in this study. The observed and initial concentrations of total VOCs (TVOC) were 12.0 ± 5.1 and 16.0 ± 7.4 ppbv, respectively. Throughout the observation period, alkenes had the most prominent photochemical losses (58.2%), followed by aromatic hydrocarbons (23.1%), accounting for 80.6% and 6.9% of the total losses, respectively. During high O3 episodes, the photochemical loss of VOCs was 6.9 times higher than that during the cleaning period. Alkene losses (exceeding 67.3%), specifically losses of isoprene, propylene, ethylene, and n-butene, dominated the total losses of VOCs during the O3 increase period. Eight sources of VOCs were identified by positive matrix factorization (PMF) based on the observed and initial concentration data (OC-PMF and IC-PMF, respectively). Concentrations of all emission sources in the OC-PMF were underestimated by 2.4%–57.1%. Moreover, the contribution of each emission source was over- or underestimated compared with that in case of the IC-PMF. The contributions of biogenic and motor vehicle exhaust emissions were underestimated by 5.3 and 2.8 percentage points, respectively, which was associated with substantial oxidation of the emitted high-reactive species. The contributions of coal/biomass burning and natural gas were overestimated by 2.4 and 3.9 percentage points, respectively, which were related to the emission of low-reactive species (acetylene, ethane, and propane). Based on our results, the photochemical losses of VOCs grossly affect their source apportionment and O3 formation. Thus, photochemical losses of VOCs must be thoroughly accounted to establish a precise scientific foundation for air-pollution control strategies.

Volatile organic compounds during routine production and planned shutdown of a petrochemical refinery: Emission characteristics, source and risk assessment

During the routine production and planned shutdown of a petrochemical refinery in China, ambient volatile organic compound (VOC) data were continuously determined by an online monitoring system, and VOC characteristics, source apportionment, and health risks were calculated based on those data. The data showed that the total VOC concentration emitted during the planned shutdown period was significantly higher than that under daily production conditions, especially the alkane concentration, which increased from 137.4 μg m−3 to 481.8 μg m−3. A source apportionment study was performed using a positive matrix factorization model based on VOC data collected during different sampling times. The contributions of petroleum refinery emissions increased from 63.8% during routine production to 79.4% during the shutdown period. In addition, carcinogenic and noncarcinogenic risk assessment revealed that workers could be under higher acute and chronic health risks during the shutdown and maintenance period than during the routine production of the refinery. The results also indicated that VOCs emitted during maintenance might have more influence on public health. Therefore, more attention should be paid to the emission characteristics and source apportionment of VOCs during planned shutdowns. This work provides valuable data that can help regulatory agencies formulate VOC control strategies during routine production and shutdown maintenance in petrochemical refineries.

Volatile organic compounds emitted by conventional and “green” cleaning products in the U.S. market

Exposure to cleaning products has been associated with harm to the respiratory system, neurotoxicity, harm to the reproductive system, and elevated risk of cancer, with greatest adverse impacts for workers exposed in an occupational setting. Social and consumer interest in cleaning products that are safer for health created a market category of “green” products defined here as products advertised as healthier, non-toxic, or free from harmful chemicals as well as products with a third-party certification for safety or environmental features. In the present study we examined the air quality impacts of cleaning products and air fresheners, measuring the number, concentrations, and emission factors of volatile organic compounds (VOCs) in an air chamber following product application. Across seven common product categories, 30 products were tested overall including 14 conventional, 9 identified as “green” with fragrance, and 7 identified as “green” and fragrance-free. A total of 530 unique VOCs were quantified with 205 additional VOCs detected below the limits of quantification. Of the quantifiable VOCs, 193 were considered hazardous according to either the California's Department of Toxic Substances Control Candidate Chemicals List or the European Chemical Agency's Classification and Labeling Inventory. The total concentration of VOCs and total emission factors across all products with detections ranged from below limits of detection to 18,708 μg/m3, 38,035 μg/g product and 3803 μg/application. Greater total concentration, total emission factors, and numbers of VOCs were generally observed in conventional cleaning products compared to products identified as “green”, particularly compared to fragrance-free products. A hazard index approach was utilized to assess relative risk from measured VOC emissions. The five products with the highest hazard indices were conventional products with emissions of 2-butoxyethanol, isopropanol, toluene and chloroform. Overall, this analysis suggests that the use of “green” cleaning products, especially fragrance-free products, may reduce exposure to VOC emissions.

Volatile Organic Compounds in Disposable Diapers and Baby Wipes in the US: A Survey of Products and Health Risks.

Many thousands of diapers are worn by young children and the elderly, who have thin and sensitive skin that is highly vulnerable to chemicals, including volatile organic compounds (VOCs) that may be ingredients of these products or present as inadvertent or residual components. The levels and potential health risks of VOCs in diapers have not been reported previously. In this study, we collected 31 disposable hygiene products in the US market based on market share and analyzed 98 target VOCs using purge and trap sampling and thermal desorption/gas chromatography/mass spectrometer analysis. Exposures and risks were modeled using reasonable upper level exposure scenarios. Adult diapers contained the highest total target VOC concentration (median level of 23.5 μg/g), and the predominant VOCs were alkanes. In some diapers, the estimated noncancer risk from these VOCs was sometimes very large (hazard quotient of 1609) due to n-heptane. Baby diapers contained several known or suspected carcinogens, including benzene and 1,4-dioxane, and the lifetime cancer risk from some diapers approached 1 per million under a worst-case scenario. Store-brand products had higher levels of VOCs than generic brands, and products labeled "organic" or "for sensitive skin" did not necessarily have lower levels. Our results show that toxic VOCs were found in all tested disposable diapers and wipes at trace levels, and risks from using some diapers in high use exposure scenarios are high enough to warrant additional attention and possibly corrective measures. We recommend eliminating and monitoring toxic ingredients and disclosing all chemicals that may be in these products.

Experimental Study of the TVOC Distribution in a Car Cabin

The vehicle in-cabin is subject to several types of pollutants infiltrating from the outdoors or emitted directly inside it, such as Volatile Organic Compounds (VOCs). The concentration of TVOC (total volatile organic compounds) is the result of the emission from different equipment surfaces that compose the car cabin. In the present study, the experimental characterization of TVOC emission from the interior surfaces of a car cabin is discussed by considering the influence of two parameters: the temperature and ventilation modes. A measurement location grid was used to measure TVOC’s emissions from 267 points on all surfaces of the car’s interior equipment. Three different temperatures and two ventilation modes (recirculation and outdoor air) were investigated. The results indicate that the concentration of TVOC increases with the temperature inside the cabin with a contribution that varies with the type of cabin equipment including the dashboard, center console, seats, and carpets. On the other hand, the concentration distributions of TVOC showed relative differences of 10–13% and 2–5% for surface and volumetric measurements, respectively. This implies no preferential positioning of the in-cabin probe for TVOC volumetric concentration measurements. In addition, the recirculation ventilation mode results in a higher accumulation of TVOC; therefore, higher concentrations are measured.

Emission characteristics of naphthalene from ship exhausts under global sulfur cap

The global sulfur limit regulation mandates the use of 0.5 % low sulfur fuel oil (LSFO) to reduce emissions of sulfur oxides (SOx), nitrogen oxides (NOx), and particulate matter (PM). However, the addition of naphthalene (Nap) to LSFO to stabilize its quality has led to an increase in polycyclic aromatic hydrocarbons (PAHs), with Nap being the main pollutant. This study investigates the effects of Nap in ship exhaust by analyzing the emission concentrations of volatile organic compounds (VOCs) and Nap in the exhaust of 16 ships, including 2 container ships, 6 bulk carriers, 1 tanker, 2 ferries, 3 fishing vessels, and 2 harbor crafts, based on USEPA method TO-15A. The results show that the percentage of Nap emissions in the exhaust gases of the 16 ship engines ranged from 77 % to 97 % of the total volatile organic compound (TVOC). The Nap concentration in the exhaust of fishing vessels, tanker, and harbor craft exceeded the occupational exposure limit of 50,000 μg/m3, with fishing vessels having the highest TVOC and Nap concentrations. The enhanced Nap emission in the air degrades air quality in port cities and poses an obvious potential public health risk. While the benefits of the global sulfur cap are being secured, additional efforts should be made to reduce the undetected side effects. Alternative stabilizers of LSFO should be considered, or Nap emission control should be boosted to mitigate the potential negative impact on harbor air quality.

Environmental hazard reduction and anti-aging enhancement of steel slag powder-asphalt mastic based on TiO2@UiO-67 composites

Steel slag asphalt pavements (SAPs) will deteriorate during the production and service process, bringing heavy metal ions leaching contamination and irregular release of Volatile Organic Compounds (VOCs), which pose great challenges to maintenance and ecological environment. TiO2@UiO-67 composites were synthesized, their basic physical-chemical properties were investigated, and they were applied to SAPs to prepare an eco-friendly steel slag powder-asphalt mastic (ESAM) with multiple effects of anti-aging, heavy metal ions reduction, and VOCs emission inhibition. The rheological behavior of ESAM was explored, and the anti-aging, heavy metal inhibition, and VOCs reduction mechanism was investigated. The results showed that TiO2@UiO-67 composites with excellent properties such as large surface area, high activity and stability, powerful adsorption ability, controlled structure, and specific functional group/targeted adsorption were prepared. Some terminal hydroxyl groups were reacted with reactive radicals to prevent the growth of asphalt chain segments by reducing the aging of asphalt. The binding energy and adsorption between UiO-67 with heavy metal ions and VOCs were simulated by Materials Studio (MS), and the results showed that the recovery of Cr (VI) was up to 57.7% and the reaction proceeded spontaneously. In addition, the conjugated system, the molecular size and the spatial site resistance synergistically reduced Category 1 carcinogens by up to 85.6%, ultimately reducing the total emission concentration of VOCs by 65.4%. It provides theoretical guidance for the application of TiO2@UiO-67 composites in SAPs, and technical feasibility for anti-aging, and pollutant emission reduction strategies for SAPs.

Analyzing indoor air pollutants in naturally ventilated athletic facilities. A case of study

Better indoor air quality (IAQ) lowers the exposure to air pollutants that can lead to decreased lung function, and exacerbation of common recurring respiratory conditions, such as asthma. Due to the higher respiratory rate, these adverse effects are particularly dangerous for athletes during exercise. Thus, investigating, and mitigating exposure to air pollutants during exercise is necessary in athletic centers. Among such facilities, cross-training gymnasiums are becoming increasingly popular and are commonly not equipped with HVAC systems, relying solely on natural ventilation to create a comfortable and healthy indoor environment. This study investigated the impact of 16 scenarios combining natural ventilation, fans, and air cleaner, on the IAQ of an athletic facility in San Antonio, TX, USA. For this purpose, occupancy, Carbon Dioxide (CO2), Carbon Monoxide (CO), Total Volatile Organic Compounds (TVOC), Particulate Matter (PM), as well as indoor and outdoor air temperature and relative humidity levels were monitored for 3 months in 5-min intervals to identify health threatening patterns. Results showed that some ventilation scenarios presented high concentrations of CO2, TVOC and PM exceeding the recommended limit values, while CO did not present concerning levels regardless of the ventilation strategy. Temperature levels indoors were consistently higher than outdoors, while relative humidity levels were lower inside. Remarkably, air filtration did not show a significant impact on IAQ in any of the analyzed scenarios. These results prove that it is essential to optimize the natural ventilation and occupancy in order to reduce the exposure to air pollutants in naturally ventilated fitness centers.

Measurements of Volatile Organic Compounds at a rural site in India: Variability and sources during the seasonal transition

Volatile Organic Compounds (VOCs) play a vital role in tropospheric ozone formation that controls the oxidative capacity of the troposphere. A total of 31 potential ozone precursor VOCs have been measured at a tropical rural site, Gadanki (13.5°N, 79.2°E) in Southern peninsular India. This study provides the primary information about different VOCs, their chemical classification and potential sources. There is a strong seasonal and diurnal variability among the VOC composition. n-Decane and n-dodecane dominate the other VOCs and contribute to a large fraction (>50 %) of the concentration of total VOCs (TVOCs) in winter and summer, monsoon is dominated by n-dodecane and post monsoon season has been dominated by ethane emissions. The source apportionment using interspecies correlation and Positive Matrix Factorisation (PMF) analysis resulted in four potential emission source factors namely biogenic, biomass burning/biofuel, fossil fuel and natural gas emissions. Winter and summer seasons have been dominated by VOCs originating from biomass burning/biofuel factors, monsoon has been dominated by biogenic emissions and post-monsoon season has been dominated by natural gas emissions. Even though it is a rural site, there are significant finger prints of anthropogenic emissions in the form of fossil fuel and natural gas most probably due to an adjacent national highway and long range transport. However, for the overall period, the VOCs emitted from biogenic and biomass burning together dominate the other two factors, indicating the expected source factor behaviour of a rural atmosphere.