Total Volatile Organic Compounds Levels Research Articles

Volatile organic compounds removal by means of a felt-based living wall to improve indoor air quality

Currently, the population spends most of the time in indoor environments, which makes Indoor Air Quality (IAQ) very important for health and comfort. As vegetation can act as a biofilter capturing air pollutants, this study aims to assess the effectiveness of a living wall module in the removal of the Total Volatile Organic Compounds (TVOCs) for IAQ improvement. An airtight glass chamber was used to release contaminants, monitoring the TVOCs both with the chamber empty (control) and with a small Fytotextile® living wall module planted with Nephrolepis exaltata L. A substantial reduction of TVOCs was observed when the living wall was inside the chamber. In few hours, TVOCs levels were reduced below the recommended limit (following Spanish regulations). More tests are recommended considering different plant species and other variables related to the IAQ.

Potential of Passive Sampling and Plant Absorption to Quantify Inhalation Exposure to Volatile Organic Compounds

Emission of volatile organic compounds (VOCs) from photocopiers was investigated to assess the potential health impacts on inhalation exposure to VOCs. VOCs samples were collected during working hours using SKC VOCs 575 series passive sample. Twenty-one quantified VOCs were measured and analyzed by GC-MS/MS. The results showed that the total VOCs concentration emitted in the photocopy centers A and B were 2.29×104 and 2.32×104 µg/m3, respectively. The highest detected chemical was trans-1,2-Dichloroethene at about 2.18×104 (photocopy center A) and 2.15×104 µg/m3 (photocopy center B (The results reveal that the non-carcinogenic risk for inhalation exposure to m-Xylene, p-Xylene, and trans-1,2-Dichloroethene were in the range 0.94-1.53 and 1.19-1.79 and 51.54-52.23, respectively, resulting in the hazard index (HI) of non-carcinogenic VOCs in total being greater than 1.0. This indicated that the cumulative effects of inhalation exposure to VOCs at low concentrations should be of concern, even though it does not exceed the occupational exposure limits and Threshold Limit Values-Time Weighted Average for the mixtures (TLV-TWAmix). Plants display a greener solution to reduce indoor air pollution. The bio-concentration levels of total VOCs in Epipremnum aureum were noted as 74.71 to 174.42, signifying that E. aureum is effective for removal of VOCs naturally and sustainably.

Spatial and seasonal variation of air quality in different microenvironments of a technical university in India

The present study aims to assess spatial and seasonal variations of indoor air quality (IAQ) among ten different indoor microenvironments of a technical university in India. Particulate matters (PM 10 and PM 2.5 ), total volatile organic compounds (TVOCs), carbon dioxide (CO 2 ), and indoor environmental quality (IEQ) indicators (i.e. temperature, relative humidity, and ventilation) were monitored during monsoon, winter and summer seasons from August 2018 to June 2019. The occupants’ perception about IAQ of studied microenvironments was analysed from 137 valid responses. The IAQ was found varying significantly (P < 0.05) among the studied microenvironments. The highest concentrations for indoor PM 10 , PM 2.5 and CO 2 were found in lecture halls with concentration exceeding the recommended guidelines values and standards; whereas the higher TVOC levels with exceeding the threshold limit were recorded in the laboratories. Further, the ventilation rate in the studied lecture halls and offices were found below the recommended ASHRAE values. Indoor concentrations of PM 10 , PM 2.5 , and TVOC showed strong seasonal variation (P < 0.05). PM 10 and PM 2.5 concentrations were found higher in the winter season, ranging from 1.8 μg/m 3 to 159.7 μg/m 3 and from 18.2 μg/m 3 to 108 μg/m 3 , respectively. The indoor microenvironments having natural ventilation with open windows had shown higher seasonal variation compared to an air-conditioned microenvironment. Indoor to outdoor (I/O) ratios of PM 2.5 , TVOC and CO 2 concentrations were found to be greater than 1. Indoor activities, ventilation and occupancy, were responsible for seasonal and spatial variability among indoor microenvironments. • IAQ varied significantly among microenvironments and across the seasons. • Indoor to outdoor ratio was greater than 1 for PM 2.5 , TVOC and CO 2. • Naturally ventilated microenvironments had shown higher seasonal variations. • PM 10 , PM 2.5 , and CO 2 exceeded the recommended health standards.

Seasonal Pollution Characteristics and Analysis of the Sources of Atmospheric VOCs in Chengdu Urban Area

To investigate the seasonal variations in the concentrations of atmospheric volatile organic compounds (VOCs) in the urban area of Chengdu, VOC species were monitored from December 2018 to November 2019, and the concentrations, chemical composition, chemical reactivity, and sources of VOCs were analyzed. Average volume fraction of VOCs in spring, summer, autumn, and winter are 32.29×10-9, 36.25×10-9, 40.92×10-9, and 49.48×10-9, respectively. The concentrations in winter are significantly higher than the winter concentrations measured in other areas. There is no significant difference between VOC concentrations in spring and summer, but component concentrations vary from season to season. In winter, alkanes account for the largest proportion of total VOCs owing to vehicle emissions. The proportion of oxygen (nitrogen)-containing volatile organic compounds in summer and autumn is much higher than that in spring and winter. Volatile emissions from primary sources and secondary conversions have a great contribution. The average concentration of key components of VOCs in different seasons did not change significantly. C2-C4 alkanes, ethylene, acetylene, and dichloromethane concentrations may be significantly affected by vehicle exhaust, oil and gas volatilization, solvent use, and LPG fuel use. ·OH consumption rate and OFP calculations show that key active species are mainly m/p-xylene, ethylene, propylene, 1-hexene, toluene, isopentane, and n-butane. Therefore, these species should be given priority in emissions control measures. Since the temperature in spring and summer is higher than in autumn and winter, and the UV rays are more intense, PMF analysis reveals the natural sources and the secondary emission sources as the major sources. The oil and gas volatilization source contributes to 9% of VOC concentrations in summer. The major VOC sources in autumn and winter are vehicle exhaust and combustion sources. Emissions from the combustion sources contribute to 25% and emissions from the catering sources in autumn and winter contribute to 9% of total VOC levels.

Exploring Volatile Organic Compound Exposure and Its Association with Wheezing in Children under 36 Months: A Cross-Sectional Study in South Lisbon, Portugal.

Air quality and other environmental factors are gaining importance in public health policies. Some volatile organic compounds (VOCs) have been associated with asthma and symptoms of respiratory disease such as wheezing. The aim of this study was to measure the concentration of Total VOCs and assess their possible association with the occurrence of wheezing episodes in children under 36 months of age, in a region south of Lisbon, Portugal. A cross-sectional study was performed from October 2015 to March 2016. The sample of children under 36 months of age was selected by convenience, by inviting parents to take part in the study. A survey was applied to collect information on bedroom features, as well as to verify the occurrence of wheezing episodes. The indoor air quality parameters of bedrooms were measured using three 3M Quest® EVM-7 environmental monitors. In total, 34.4% of infants had had wheezing episodes since birth, with 86.7% of these presenting at least one episode in the previous 12 months. Total VOC levels were above the reference values in 48% of the analyzed bedrooms. No significant association of VOC exposure in a domestic setting with episodes of wheezing was found. However, children living in households with smokers were 4 times more likely to develop wheezing episodes. Thus, this study provides relevant information that warrants further studies to assess infant exposure to indoor air pollution and parental smoking in a residential context.

Hot - Spot summertime levels and potential sources of volatile organic compounds (VOC) on roads around Çanakkale and Kilitbahir Harbors across Dardanelles Strait

Organic air pollutants have considerable influence particularly on atmospheric chemistry, compared to other air pollutants. Traffic is one of the major sources of air pollutants occurred in Çanakkale atmosphere by both remarkable road and marine traffic loads around the harbors. The aims of this study were finding the daily, week/weekend, and spatial variations of VOC at multiple sampling points of Çanakkale and Kilitbahir. In this study, active air samples were collected from the major roads of Kilitbahir and Çanakkale Harbors during rush hours and off-peak in 2018 summer. According to the measurement results, average levels of total volatile organic compounds (TVOC) were around 129 μg/m3 in Çanakkale and 93 μg/m3 in Kilitbahir. Toluene was the most abundant compound. Average B: T: E: X ratio was calculated as 2.4:7.0:1:5.5 in Çanakkale and 3.2:7.6:1:5.2 in Kilitbahir. According to the sampling points of both locations, levels of TVOC, benzene, toluene, and m,p-xylene in Çanakkale and toluene levels in Kilitbahir showed statistically significant differences (p < 0.05). Also, benzene, which was already classified as a human carcinogen, varied diurnally in Kilitbahir (p < 0.05). Toluene levels varied between week and weekend days (p < 0.05). Moreover, measured VOC levels were compared with air quality monitoring station (AQMS) data and meteorological parameters. TVOC levels showed positive correlations with SO2 and PM10 (p < 0.05). Furthermore, a multivariate factor analysis applied to data set including VOC measurements, AQMS data, and meteorological parameters implied that traffic is the predominant factor influencing the air quality around the study sites.

Potential Chemical Stressors Emitted During the Operation of Machines in the Digital Printing Process

ABSTRACT The digital printing process contributes to the quality of indoor air through the emission of chemical stressors such as total volatile organic compounds (TVOCs) and suspended particulate matter (SPM). The concentration levels of SPM and TVOCs were determined using the gravimetric and gas chromatography method, respectively. The results show that the digital printing machines and the cutting machine do not produce PM2.5 particles. The significant cumulative mass concentrations of PM10 suspended particles of 9.91 μg/m3 for a single-colour digital printing machine, 4.45 μg/m3 for a four-colour digital printing machine, and 2.02 μg/m3 for a cutting machine, were detected. By comparing the cumulative values of TVOC concentration levels measured, it can be concluded that the values have been 4 to 12 times higher for the four-colour digital printing machine than for the single-colour digital printing machine. Namely, the TVOC concentration levels measured for the four-colour digital printing machine ranged from 28.69 to 57.30 mg/m3, while the values for the single-colour digital printing machine ranged from 2.31 to 13.51 mg/m3. Considering the fact that there are no standards of quality of indoor air in printing offices defined in the Republic of Serbia, the results obtained could represent a valid basis and a worthy guideline for the definition of values necessary for the indoor air quality assessment.

Characteristics, sources and regional inter-transport of ambient volatile organic compounds in a city located downwind of several large coke production bases in China

Abstract Volatile organic compounds (VOCs) are important precursors of atmospheric ozone (O3) and particulate matter (PM). Taiyuan, located downwind of several large coke production bases, is a heavily polluted city in China, with high concentrations of PM and increasing concentrations of ground-level O3. In this study, 116 air samples were collected in four seasons of 2015 and analyzed for non-methane hydrocarbon and halocarbon species. The annual average concentration of the total VOCs (TVOCs) in Taiyuan was observed to be higher and slightly lower than that in Beijing and Shenzhen, respectively. High concentrations of benzene and a high benzene to toluene (B/T) ratio were the most evident features. TVOCs levels showed significant seasonal variations, increasing from spring (31.08 ppbv) to winter (67.33 ppbv). Although the concentrations of many air pollutants declined to a minimum, TVOCs continued to show high levels during the summer. Six sources were resolved using positive matrix factorization (PMF), and results indicated that coking processes was the largest contributor (32.56%) to ambient VOCs in Taiyuan, followed by coal and biomass combustion (23.25%). In winter, the contributions of combustion sources and liquefied petroleum gas/natural gas/coalbed methane (LPG/NG/CBM) usage significantly increased compared with those in other seasons. The coking bases located upwind of Taiyuan in the southwestern and western directions were the major potential source regions of coking related VOCs, as indicated using the potential source contribution function (PSCF) analysis. More than 70%, 40% and 80% of the air masses were transported from Taiyuan to the Beijing-Tianjin-Hebei (BTH) region during spring, autumn and winter, respectively. This study indicated that the coke production bases in Shanxi should be listed as the key regions to address the air pollution problems throughout north China. In addition, the combustion source in Taiyuan was associated with high local emissions, while Hebei province located in the northeastern direction, Shaanxi and Inner Mongolia located in the northwestern direction were the potential sources of solvent and LPG/NG/CBM usage, respectively.

Emissions and health risks from the use of 3D printers in an occupational setting

ABSTRACTThe aim of this study was to determine concentrations of particulates and volatile organic compounds (VOCs) emitted from 3D printers using polylactic acid (PLA) filaments at a university workroom to assess exposure and health risks in an occupational setting. Under typical-case (one printer) and worst-case (three printers operating simultaneously) scenarios, particulate concentration (total and respirable), VOCs and formaldehyde were measured. Air samples were collected in the printing room and adjacent hallway. Size-resolved levels of nano-diameter particles were also collected in the printing room. Total particulate levels were higher in the worst-case scenario (0.7 mg/m3) vs. typical-case scenario (0.3 mg/m3). Respirable particulate and formaldehyde concentrations were similar between the two scenarios. Size-resolved measurements showed that most particles ranged from approximately 27 to 116 nm. Total VOC levels were approximately 6-fold higher during the worst-case scenario vs. typical situation with isopropyl alcohol being the predominant VOC. Airborne concentrations in the hallway were generally lower than inside the printing room. All measurements were below their respective occupational exposure limits. In summary, emissions of particulates and VOCs increased when multiple 3D printers were operating simultaneously. Airborne levels in the adjacent hallway were similar between the two scenarios. Overall, data suggest a low risk of significant and persistent adverse health effects. Nevertheless, the health effects attributed to 3D printing are not fully known and adherence to good hygiene principles is recommended during use of this technology.

Volatile organic compound emission in a university printing press facility in eastern North Carolina

Printing presses are known to release volatile organic compounds (VOCs) that may pose health risks to workers. The purpose of this study was to assess the area airborne total volatile organic compounds (TVOCs) and toluene concentrations in an eastern North Carolina university printing facility. Real-time TVOC concentrations for ∼8 h were measured using photoionization detectors during each sampling day in the facility offset and digital printing areas. Air samples were collected in the offset printing area using activated charcoal tubes to determine the 8-h time-weighted-average toluene exposure. The mean daily TVOC concentrations (n = 38) had an overall average of 6.68 ± 3.25 ppm. The mean daily TVOC concentrations in the offset printing area (8.99 ± 2.93 ppm) were significantly higher ( p &lt;0.01) than that in the digital printing area (4.38 ± 1.38 ppm), which may be attributed to the type of printing equipment used. The highest mean daily TVOC concentration (15.77 ± 5.69 ppm) and the maximum 1-s TVOC level (42.59 ppm) were measured in the offset printing area. The overall mean toluene concentration (n = 9) was 0.14 ± 0.10 ppm (range of 0.04–0.31 ppm). Findings of this study will help in further understanding the offset and digital printing TVOC exposures and in planning to improve worker protection in printing and other similar industries.

Variability of Total Volatile Organic Compounds (TVOC) in the Indoor Air of Retail Stores.

Volatile organic compounds (VOCs) are released to the indoor air of retail stores from numerous products and activities, but available literature lacks a systematic understanding of the variability of VOC concentrations. In this study, we measured concentrations of total VOCs (TVOC) in 32 retail stores using a high-sensitivity photoionization detector (PID). Indoor thermal comfort parameters, including temperature, relative humidity, and air velocity, were simultaneously measured using an anemometer. The store-level TVOC concentrations ranged from 30 to 869 ppb and exceeded the LEED guideline in 31 stores. TVOC levels were notably high in hardware stores (median = 536 ppb, p = 0.0002) and paints, household, and home accessories sections within stores (p < 0.05). TVOC levels were elevated in mornings and evenings, possibly due to low ventilation and cleaning activities at the beginning and end of business hours. The between-store, within-store, and temporal variations accounted for 85%, 0.5%, and 14% of the total variance, respectively. The variance structure suggested that in-store VOC concentrations were predominantly driven by their source location, and representative monitoring should first consider covering various store types. Current store VOC levels present health concerns, but further studies are needed to evaluate risks among customers.

An eight-city study of volatile organic compounds in Chinese residences: Compounds, concentrations, and characteristics

This study conducted on-site measurements of indoor volatile organic compounds (VOCs) in 251 occupied residences in China, with multiple visits throughout a whole year. Over 1000 samples were collected for measurement of VOCs in 8 cities, covering different climate regions. Overall, the concentrations of total VOCs (TVOCs) in occupied residences are in the range of 104–1151 μg/m3, with 20% of the samples over the Chinese standard of 600 μg/m3. A higher concentration was evident in the summer (mean = 705 μg/m3) compared to other seasons, especially winter (mean = 289 μg/m3). The TVOCs of residences in areas with central heating (severe cold regions and cold regions) are generally higher than those in areas without central heating. In winter, temperature was the dominant factor, whereas in summer, the building infiltration rate was the key factor influencing the indoor TVOC levels. The TVOCs concentration was also found to be directly proportional to the city economy level. Twenty-nine VOC species with a detection frequency higher than 40% were identified in all samples. Toluene is the most common VOC, with the highest detection rate (90%). The median concentration for a single VOC was between 1 and 14 μg/m3. Aldehydes were found to be the largest contributors to total VOCs in the Chinese residential buildings (mass proportion 22%), followed by benzene series (20%), alkenes (18%), and alkanes (15%). Aldehydes, especially long-chain saturated carbonyls, are likely to be the characteristic VOCs in the Chinese dwellings, with Chinese cooking as the major emission source. In addition, n-butane/i-butane showed maximum concentration in some residences (approximately 105 μg/m3 higher than other VOCs) owing to cooking fuel.

Does plant species selection in functional active green walls influence VOC phytoremediation efficiency?

Volatile organic compounds (VOCs) are of public concern due to their adverse health effects. Botanical air filtration is a promising technology for reducing indoor air contaminants, but the underlying mechanisms are not fully understood. This study assessed active botanical biofilters for their single-pass removal efficiency (SPRE) for benzene, ethyl acetate and ambient total volatile organic compounds (TVOCs), at concentrations of in situ relevance. Biofilters containing four plant species (Chlorophytum orchidastrum, Nematanthus glabra, Nephrolepis cordifolia 'duffii' and Schefflera arboricola) were compared to discern whether plant selection influenced VOC SPRE. Amongst all tested plant species, benzene SPREs were between 45.54 and 59.50%, with N. glabra the most efficient. The botanical biofilters removed 32.36-91.19% of ethyl acetate, with C. orchidastrum and S. arboricola recording significantly higher ethyl acetate SPREs than N. glabra and N. cordifolia. These findings thus indicate that plant type influences botanical biofilter VOC removal. It is proposed that ethyl acetate SPREs were dependent on hydrophilic adsorbent sites, with increasing root surface area, root diameter and root mass all associated with increasing ethyl acetate SPRE. The high benzene SPRE of N. glabra is likely due to the high wax content in its leaf cuticles. The SPREs for the relatively low levels of ambient TVOCs were consistent amongst plant species, providing no evidence to suggest that in situ TVOC removal is influenced by plant choice. Nonetheless, as inter-species differences do exist for some VOCs, botanical biofilters using a mixture of plants is proposed.

A Low-Power Wireless Multichannel Gas Sensing System Based on a Capacitive Micromachined Ultrasonic Transducer (CMUT) Array

Detection of volatile organic compounds (VOCs), challenged by their diversity and similarity, is gaining much attention due to concerns about adverse health effects they cause, along with intensifying development efforts in wireless sensor nodes. Precise identification of volatiles may be subject to the sensitivity and selectivity of a sensor itself and the proximity of the sensor to the source, necessitating power-efficient and portable/wearable sensing systems. The metal-oxide sensors, commonly employed for detection of VOCs, are not power efficient, due to the required heating element, and lack the selectivity, thus reporting only the total VOC level. In this paper, we present a complete low-power wireless gas-sensing system based a capacitive micromachined ultrasonic transducer array, which is known to have several advantages such as high mass sensitivity, easy implementation of a multielement structure, and high selectivity upon polymer coating. We took a holistic approach to designing the sensing elements and the custom integrated circuit (IC) as well as to operating the system, resulting in a small self-contained sensor node (38-mm detect-weight diameter and 16-mm detect-weight height). The chemical-sensing capability of the system has been validated with ethanol, achieving 120-ppb limit-of-detection while the sensor array, including the IC and the power management unit, consuming 80- $\mu \text{W}$ average power with power cycling by actively taking measurements for 3 s detect-weight per minute. The presented system will eventually provide a ubiquitous tool to identify VOCs with the help of multivariate data analysis.

A Survey on Distributed Greenhouse Gases Monitoring Systems

Monitoring of air quality represents a major task, due to the direct impact of pollution on human health. Pollution has been further aggravated by the progresses that have taken place in the last decades: traffic growth, traffic noise in cities and growth of urban areas, rising cities, increased energy consumption, industrialization, and economic development. Global warming and acid rain are the results of these factors; thus, air quality is essential to be monitored. This survey presents a set of researches and applications related to air quality monitoring, aimed to detect, measure, collect and process data aggregated from sensors, such as gas sensors for sensing concentration of gases such as CO2 (Carbon dioxide), relative humidity, temperature, TVOC (Total Volatile Organic Compounds), PM (particulate matter) and noise level. Based on some processes, users will be able to see the polluted areas on the map. The paper presents a state of the art of air monitoring systems, noise monitoring systems, air pollution systems. Also, the paper proposes a distributed greenhouse monitoring system for pollution measurement and control.

Seasonal variation of air quality in hospitals with indoor–outdoor correlations

This study involved a seasonal exposure assessment in a hospital environment using several air quality indicators including carbon monoxide (CO), carbon dioxide (CO2), particulate matter (PM10 and PM2.5), and total volatile organic compounds (TVOCs). We examined the distribution of and variation in the indoor and outdoor pollutant concentrations in 12 working areas across three hospitals, with an emphasis on capturing seasonal variations. We assessed correlations between measured indoor and outdoor levels to quantify the importance of indoor sources on air quality relative to outdoor sources. Our results indicated that while indoor and outdoor CO levels were below air quality standards/guidelines, measured PM2.5 and PM10 concentrations at several locations exceeded the standards 2- to 3.5-fold. We generally recorded higher indoor PM levels during the warm season, particularly during regional desert storm events. The ingress of particles from the outdoor to indoor environment was evident with high correlations between indoor and outdoor PM2.5 (r between 0.83 and 0.92) and PM10 (r between 0.74 and 0.86) levels, particularly during the warm season. Indoor to outdoor (I/O) ratios of PM2.5 and PM10 were mostly < 1. In contrast, indoor levels of CO2 and TVOCs exceeded outdoor concentrations during both the warm and cold seasons with I/O ratios >1 across all sampling locations. Our paper concludes with implications of high PM exposure and a suggested management framework for limiting such exposure in hospitals.

Indoor air quality of newly built low-energy preschools – Are chemical emissions reduced in houses with eco-labelled building materials?

The use of an airtight frame in low-energy buildings could increase the risk of health-related problems, such as allergies and sick building syndromes (SBS), associated with chemical emissions from building materials, especially if the ventilation system is not functioning properly. In this study, the indoor air quality (IAQ) was investigated in newly built low-energy and conventional preschools by monitoring the indoor air temperature, relative humidity, particle-size distribution and levels of carbon dioxide (CO2), nitrogen dioxide (NO2), formaldehyde and total volatile organic compounds (TVOC). The thermal comfort was satisfactory in all preschools, with average indoor air temperature and a relative humidity at 21.4°C and 36%, respectively. The highest levels of TVOC (range: 130–1650 µg/m3 toluene equivalents) and formaldehyde (range: 1.9–28.8 µg/m3) occurred during the first sampling period associated with strong emissions from building materials. However, those preschools constructed with environmental friendly building materials (such as Swan Eco-label) had lower initial TVOC levels compared to those preschools constructed with conventional building materials. The IAQ and indoor chemical emissions were also strongly dependent on the functioning of the ventilation system. Preliminary risk assessment indicated that exposure to acrolein and crotonaldehyde might lead to respiratory-tract irritation among occupants.

In-vehicle exposure of carbon monoxide, nitrogen dioxide and total volatile organic compounds from ethanol versus gasoline fuel

Alternative fuels, such as ethanol-based fuels (E85), have attracted attention as promising approaches for reducing emissions from on-road mobile sources. However, the in-vehicle exposure to pollutants when using E85 has not yet been addressed. This study aims to examine the contribution of E85 to in-vehicle exposure to carbon monoxide (CO), nitrogen dioxide (NO2) and total volatile organic compounds (TVOCs) under different scenarios. A one-compartment mass-balance model incorporating outdoor concentration, infiltration, makeup and recirculated air exchange rate (λ), volume of the vehicle (V) and the internal emissions source (E) is developed to obtain the in-vehicle concentrations. The intake fraction (pollutant mass inhaled by an exposed individual per unit release of pollutant) was used to estimate the mass emission rate. The results show a small increase in interior CO and TVOC concentrations for vehicles fueled by E85 compared to those fueled by gasoline, mainly due to the increase in mass emission rate resulting from the exhaust system when E85 is burned. The in-vehicle concentration of CO and TVOCs for ethanol-fueled vehicles ranged from 6.2 to 42.2 mg/m3 (5.4–36.2 ppm) and from 67.9 to 1851 (µg/m3), respectively. The maximum increases in CO and TVOC concentrations were 2 (mg/m3) and 303.3 (µg/m3), observed when the air exchange rate was 2 h−1 and the vehicle was stationary. Despite the increase in CO and TVOC levels, the penetration of E85 positively impacted in-vehicle NO2 concentrations, with a maximum reduction of 293 (µg/m3). The study also developed a mathematical model to estimate the intake fraction under different scenarios for both E85 and gasoline fuels. The difference in intake fraction of CO is estimated to be in the range (2–1) (mg of pollution is inhaled per kg emitted). The difference in intake fraction of NO2 and TVOCs ranged from 10 to 2 and from 5 to 1, respectively.

In-Cabin Air Quality during Driving and Engine Idling in Air-Conditioned Private Vehicles in Hong Kong.

Many people spend lengthy periods each day in enclosed vehicles in Hong Kong. However, comparably limited data is available about in-cabin air quality in air-conditioned private vehicles, and the car usage that may affect the air quality. Fifty-one vehicles were tested for particulate matter (PM0.3 and PM2.5), total volatile organic compounds (TVOCs), carbon monoxide (CO), carbon dioxide (CO2), airborne bacteria, and fungi levels during their routine travel journey. Ten of these vehicles were further examined for PM0.3, PM2.5, TVOCs, CO, and CO2 during engine idling. In general, during driving PM2.5 levels in-cabin reduced overtime, but not PM0.3. For TVOCs, 24% vehicles exceeded the recommended Indoor Air Quality (IAQ) level in offices and public places set by the Hong Kong Environmental Protection Department. The total volatile organic compounds (TVOC) concentration positively correlated with the age of the vehicle. Carbon monoxide (CO) levels in all of the vehicles were lower than the IAQ recommendation, while 96% vehicles exceeded the recommended CO2 level of 1000 ppmv; 16% vehicles >5000 ppmv. Microbial counts were relatively low. TVOCs levels at idle engine were higher than that during driving. Although the time we spend in vehicles is short, the potential exposure to high levels of pollutants should not be overlooked.

Levels of formaldehyde and TVOCs and influential factors of 100 underground station environments from 2013 to 2015

ABSTRACTIn this study, the environmental factors that affect airborne formaldehyde and total volatile organic compounds (TVOCs) were evaluated and the monthly variations in formaldehyde and TVOC levels in underground platforms of subway stations were compared. Formaldehyde level was determined from May 2013 to September 2015 for lines 1 to 4 of Seoul Metro. Samples for formaldehyde and TVOCs were collected at intervals of 30 min during a 60 min period, and then analyzed via high-performance liquid chromatography (HPLC) for formaldehyde and gas chromatography for TVOCs. Formaldehyde levels were correlated with depth of platform, whereas TVOC levels were negatively correlated with depth of platform. There were significant differences in levels of formaldehyde and TVOCs in 2013 and 2015 in the underground platforms. The highest levels of formaldehyde and TVOCs were in July from May to September, respectively (p < 0.05). Formaldehyde and TVOC levels varied greatly, depending on monthly variation and correlated with depth of platform. Therefore, Seoul Metro might need to manage the underground platforms at depth more carefully and further study the reasons behind the relatively high levels of formaldehyde and TVOC ranging from 12 to 22 m.