TVOC Concentrations Research Articles

Impacts of humidification process on indoor thermal comfort and air quality using portable ultrasonic humidifier

Human exposed to low level of indoor humidity will have dryness (for skin, pharyngeal, eye etc.) or respiratory symptoms, which are closely related with indoor thermal comfort and air quality. To increase indoor humidity, portable humidification facilities (e.g., ultrasonic humidifiers) are widely applied in residential buildings due to their economy and convenience. Most of the available indoor humidity-related studies were associated with health issues induced by humidity and airborne pollutants generated by humidifier. However, the studies are rarely focusing on the effects of unsteady humidification (water vapor and droplet-induced from portable humidifier) on indoor thermal environment (i.e., air temperature, humidity, thermal comfort) and indoor air quality (e.g., TVOC, particles). Thus, this work aimed to investigate the impacts of humidification process on indoor environment by experiments in an isothermal chamber. The results show that portable ultrasonic humidifier increased humidity and decreased temperature simultaneously. The unsteady air temperature curve had “ladder-like” pattern. If RH increased from 34% to 60%, air temperature and PMV (Predicted Mean Vote) were decreased by 1.5 °C and 0.2 respectively. The obvious spatial stratification phenomenon was observed for both temperature and humidity field. We also found the obvious decrease of PM and TVOC concentrations during the entire humidifying process. Compared to traditional steam humidification system, indoor portable ultrasonic humidifier could save 70% of energy consumption and 18% of exergy loss. These qualitative characteristics of indoor humidification process would facilitate for indoor humidity control in the perspectives of human health and thermal comfort.

Characteristics of VOCs Pollution in the Winter Atmosphere of a Typical Petrochemical Industry Park

Concentrations of volatile organic compounds (VOCs) in ambient air of a typical petrochemical industry park were measured using an on-line monitor (TH-300B) from December 2014 to February 2015. The composition, temporal variations, sources, and photochemical reactivity of VOCs were analyzed. Alkanes were the most abundant VOC species and contributed to 86.73% to total VOC concentrations in winter. Concentrations of TVOCs, alkanes, alkenes, and aromatic hydrocarbons were high at night and low during the day. The changes in alkane and alkene concentrations were consistent with those in TVOC concentrations. Using principal component analysis and multiple linear regression (PCA-MLR) in combination, five sources of VOCs were identified; fuel evaporation, industrial emissions, a mix of gasoline vehicle exhaust and plant emissions, diesel vehicle exhaust emissions, and fuel combustion with contributions of 60.02%, 8.50%, 2.07%, 12.21%, and 17.20%, respectively. Propylene-equivalent concentration (Propy-Equiv) and maximum incremental reactivity (MIR) method were used to calculate the contributions of VOCs measured in the study area to ozone production. Alkanes contributed most to ozone production followed by alkenes and aromatic hydrocarbons. The contribution rate of cyclopentane, n-butane, and 1-pentene were higher owing to their long photochemical age in the study area.

Field study on indoor air quality of urban apartments in severe cold region in China

An investigation on indoor air quality was carried out in urban apartments in Harbin, China. The indoor and outdoor concentrations of PM2.5, PM10, CO, CO2, SO2, NOX, TVOC, HCHO and NH3 were monitored. Simultaneously, questionnaire surveys on the indoor perception of air quality among occupants were conducted. In addition, a continuous measure on indoor air pollutants was performed during cooking period and the indoor air quality in newly-decorated urban apartments was also studied.The results showed that the indoor PM2.5 and PM10 during the space heating period, especially the haze weather period caused by heavy smog, were polluted seriously. Good linear relationships between indoor and outdoor concentrations of PM were identified in the condition of terrible outdoor air quality. In contrast, the concentrations of HCHO, CO, CO2, NOX and SO2 approximately satisfied the requirements of national standard unless the serious haze weather occurred. According to the subjective surveys, occupants could evaluate the indoor ventilation correctly, but the indoor air quality was always overestimated. Moreover, the factor of illness history of the occupants had an obvious influence on the evaluation of indoor air quality. Furthermore, cooking increased the indoor concentrations of HCHO, CO and TVOC significantly, and the indoor air quality in newly-decorated urban apartments was heavily polluted by HCHO, NH3 and TVOC.

Early Stage Design Decisions: The Role of Pre-Natural Ventilation Considerations in VOCs Emissions Mitigation in Educational Buildings

It is common that schools are designed to achieve the highest performance with the lowest cost regardless of any health considerations. Educational indoor environments have already been of particular public concern, as children have greater susceptibility to environmental pollutants than adults. It has been known that VOCs emissions dilution from finishing materials via ventilation is a straightforward and common approach. So, natural ventilation enhancement should be considered in the Early-Stage design from the site considerations to even window configurations. So, the thesis approach is to find out to what extent the Early-Stage design concerning the natural ventilation is effective on mitigation of VOCs concentration levels. Throughout the analysis of educational spaces in Glory international school in Mansoura, a classroom with west orientation will be chosen to be analyzed and compared with LEED standard concerning TVOCs concentration to find out the threat levels. There is an attitude to imagine the base case of the western classroom in different radical scenarios in the school design. These radical scenarios will be inapplicable to the base case as the architectural consequences are enormous. These scenarios will be simulated to find out the TVOCs concentration results in comparison with the base case and LEED standards.

Direct and potential risk assessment of exposure to volatile organic compounds for primary receptor associated with solvent consumption.

Rapid development of industrial production has stimulated the growth of consumption of raw and auxiliary materials including organic paints, among which volatile organic compounds (VOCs) are proved harmful to the population who inhale the polluted air based on epidemiologic studies. Therefore, new types of environment-friendly paints were developed to replace solvent-based paints (SBPs). Nevertheless, new types of paints containing VOCs failed to replace SBPs entirely due to certain disadvantages. Hence, five kinds of paints were employed in simulation experiments to assess the health risk of primary receptor including three kinds of water-based paints (WBPs) and two kinds of SBPs. Conclusions showed that mean TVOC concentration in breathing zone of primary receptor ranged from 9.5 to 13.6mg/m3 and 3.4×103 to 1.4×104mg/m3 for WBPs and SBPs, respectively. Assessments of non-cancer risk concluded that nearly one third quantified compounds exceeded corresponding thresholds for WBPs, and the maximum risk value was 101.33; for SBPs, the maximum risk value reached 50760.20, and twenty-two compounds exceeded the reference limits. The calculation of cancer risk values showed that seventeen compounds were higher than acceptable limit amongst which 1,2-dibromoethane had maximum values of 1.27×10-2 to 3.24×10-2 for WBPs; for SBPs, all quantified compounds exceeded the acceptable limit, and 82.61% VOCs were distributed in a scope larger than 1×10-3. Additionally, a removal efficiency of 60% was considered for primary receptor with personal protective equipment, and subsequent results confirmed its inability of lowering the risk resulted from hazardous VOCs. The calculated potential health risk could be applied to estimate the total health risk for both primary and secondary receptor based on consumed materials. The finding suggested that WBPs could improve VOCs exposure condition and reduce the direct and potential health risk significantly for primary receptor, although they might dissatisfy acceptable limit.

주택 실내 공기중 오염물질 농도의 동절기와 하절기 비교 분석

Purpose: The study is to measure concentrations of indoor air pollutants in housing and to analyze the characteristics of pollutants in housing indoor-air between summer and winter comparatively. The research result could be used as data for public health through indoor air quality management of existing housing and more as a reference for new housing. Method: It was investigated 24 middle class housings of metropolitan area in winter which have been built for the past 30 years. Concentration of HCHO, TVOC was investigated in living room at morning and night and concentration of <TEX>$CO_2$</TEX> was investigated in living room and master bedroom at morning and night. SKT100-X5 was used for concentration of HCHO, TVOC and ZGm053UK for concentration of <TEX>$CO_2$</TEX>. The characteristics of HCHO, TVOC, <TEX>$CO_2$</TEX> concentration in winter were analyzed and then the concentrations in winter were analyzed the concentrations in summer being preceding research comparatively. Result: Average concentration of TVOC in winter was 2.7 times more than that of TVOC in summer, average concentration of HCHO in winter was about 2.0 times more than that of HCHO in summer. Average concentration of <TEX>$CO_2$</TEX> in the morning at living room in winter was 1.3 times more than that of <TEX>$CO_2$</TEX> in summer. Average concentration of <TEX>$CO_2$</TEX> in the morning at master bedroom in winter was 1.1 times more than that of <TEX>$CO_2$</TEX> in summer. Average concentration of TVOC was 1.31 times more than that of HCHO and standard deviation of that was 1.73 times higher. Average concentration of <TEX>$CO_2$</TEX> was almost nearly close or over to 1,000ppm being criteria of the Ministry of Environment.

Experimental analysis of indoor air quality improvement achieved by using a Clean-Air Heat Pump (CAHP) air-cleaner in a ventilation system

This study investigated the air purification effect of a Clean-Air Heat Pump (CAHP) air-cleaner which combined a silica gel rotor with a heat pump to achieve air cleaning, heating and ventilation in buildings. The experiments were conducted in a field laboratory and compared a low outdoor air supply rate with CAHP air purification of recirculated air with three different outdoor air supply rates without recirculation or air cleaning. Sensory assessments of perceived air quality and chemical measurements of TVOC concentration were used to evaluate the air-cleaning performance of the CAHP. The results of the experiment showed that the operation of the CAHP significantly improved the perceived air quality in a room polluted by both human bio-effluents and building materials. At the outdoor airflow rate of 2 L/s per person, the indoor air quality with CAHP was equivalent to what was achieved in the same room with 10 L/s per person of outdoor air ventilation without air cleaning. The percentage dissatisfied was as low as 5.2% with the CAHP in operation, based on adapted perception assessment. The outdoor air supply rate can be reduced by 76% by using CAHP, as the Clean Air Delivery Rate (CADR) was over three times the outdoor air supply rate when the CAHP was in operation. The chemical measurements indicated a single-pass efficiency of over 92% for the removal of indoor air pollutants when the regeneration temperature was 60 °C. No VOC accumulation on the desiccant wheel was observed.

A pre and post evaluation of indoor air quality, ventilation, and thermal comfort in retrofitted co-operative social housing

In comparison to building energy performance, assessment of the impact of energy upgrades on indoor air quality and occupant comfort has received little attention.Concentrations of indoor air pollutants in fifteen, three bed semi-detached co-operative social dwellings were monitored before and after an energy upgrade during the winter periods of 2015 and 2016. The fifteen dwellings consisted of seven cavity wall (CW) dwellings and eight hollow block (HB) wall dwellings. Concentrations of indoor air pollutants including CO, PM2.5, CO2, TVOCs, formaldehyde, BTEX, NO2 and thermal parameters including temperature and relative humidity, were measured in the main living area and main bedroom before and after the energy upgrade.Building air tightness decreased from pre retrofit values of 9.26–10.00m3/(h.m2) @ 50 Pato an average of 5.53 m3/(h.m2) @ 50 Pa and 8.61m3/(h.m2) @ 50 Pa post retrofit (CW group and HB group, respectively). Concentrations of CO2, TVOC, and PM2.5 significantly changed post-retrofit, increasing post retrofit in both dwelling groups (CW; p = 0.014; p = 0.009; p = 0.005) (HB; p = 0.003; p = 0.032; p = 0.008). Increases in pollutant concentrations were correlated with lower building air exchange rates post retrofit. This study suggests that the energy retrofit had a positive impact on occupant comfort and building temperature; however, concentrations of some pollutants were found to increase following the retrofit.The study highlights the importance of characterising indoor air quality post energy retrofits within the overall building energy performance to ensure improved health outcomes for building occupants post retrofit.

Overall performance evaluation of underfloor air distribution system with different heights of return vents

The position of the return air vent significantly influences the performance of underfloor air distribution (UFAD) systems with split-return/exhaust configuration. While the proper height of return vent has been investigated, the emphasis of the evaluation is very much on the thermal comfort and energy saving performance under heating scenarios. In this study, the impacts of the return air vent height on the indoor air quality (IAQ), thermal comfort, and energy saving of an UFAD system for both room cooling and heating are investigated using computational fluid dynamics (CFD) approach based on simplified boundary conditions of the slot supply. The calculation of air velocity, temperature, mean age of air, CO2 and TVOCs concentrations distribution in the room with various height positions (Z=0.8m to 2.6m) of the return vents was carried out. The thermal environment indices (temperature gradient and draught rating), indoor air quality indices (mean age of air, air change efficiency, CO2 and TVOCs concentrations distribution) and energy saving are analyzed and compared against each other. The results demonstrate that descended return vents are beneficial to the energy efficiency, while the dispersion and removal of gaseous contaminants such as CO2 and TVOCs is highly sensitive to the location of return vent relative to the contaminant sources. An optimal range of location height of return vents which compromise all the aforementioned indices is recommended.In under-floor-air-distribution (UFAD) systems, the exhaust/return-split configuration is believed to be more promising than the exhaust/return-combined arrangement in terms of energy efficiency. However, how to properly position the return vents still remains an unanswered question when the thermal comfort and indoor air quality (IAQ) need to be simultaneously considered. In this study, a series of numerical computations are conducted with various height positions (Z=0.8m to 2.6m) of the return vents in order to evaluate the effects of the height of return vents in a UFAD system on the thermal comfort, contaminant removal and energy efficiency. The thermal environment indices (temperature gradient and draught rating), indoor air quality indices (mean age of air, air change efficiency, CO2 and TVOCs concentrations distribution) and energy saving are analyzed and compared against each other. The results demonstrate that descended return vents are beneficial to the energy efficiency, while the dispersion and removal of gaseous contaminants such as CO2 and TVOCs is highly sensitive to the location of return vent relative to the contaminant sources. An optimal range of location height of return vents which compromise all the aforementioned indices is recommended.

Investigations of indoor air quality of large department store buildings in China based on field measurements

This paper presents a large-scale field studies on the indoor air pollution in large multi-storey department store buildings in seven Chinese metropolitan cities. From the year 2013–2015, nine buildings equipped with centralized air-conditioning system were carefully selected for the onsite test. Results show that each building has diverse indoor thermal environment and concentrations of CO2, formaldehyde and TVOC. Mean concentrations of CO2, formaldehyde and TVOC in the measured buildings range from 560 to 997 ppm, 0.02–0.31 mg/m3 and 0.074–0.636 mg/m3 respectively. The highest rates of exceeding the standard limit in the tested buildings were found as 36.8% of CO2, 53.2% of formaldehyde and 40.3% of TVOC. There are significant correlations between indoor and outdoor concentrations of CO2, formaldehyde and TVOC. The pollutant concentrations are different in different merchandise sections. Furthermore, significant differences and colorations of the pollution concentration are revealed between that of aboveground and underground floors. A mathematical model for the calculation of the increment of fresh air for the underground floors of a department store building is proposed based on the theoretical analysis and the assumption of steady-state airflow condition. This model provides quantitative relations of a required amount of additional fresh air of the underground floor referencing to the aboveground floor of the same building. Based on this research, it is recommended that the factors of space functionality and usage as well as the location of under-aboveground floors of the department stores should be taken into account in the design and operation of the HVAC systems.

Field study on indoor health risk factors in households with schoolchildren in south-central China

A field study on indoor thermal environment and pollutants was conducted in 10 households with 10–12 years old children in Changsha, a south-central city in China. The aim is to identify and examine the main indoor pollutants which affect schoolchildren's health. The households were divided into two groups: 1) Group A, households with apparently unhealthy children, 2) Group B, households with healthy children. The findings for autumn and winter indicated that the differences in temperature and relative humidity (RH) between Groups A and B were not significant. The average concentrations of CO2, HCHO and acetaldehyde of Group A were lower than those of Group B. However, the average concentrations of PM2.5 and TVOCs of Group A were higher than those of Group B. In addition, the indoor PM2.5 concentrations in ten households, exceeded the upper limit of the Chinese national standard (75 μg/m3) and the TVOCs concentration in two households exceeded the upper limit (600 μg/m3) in winter. The average concentrations of Di(2-ethylhexyl) Phthalate (DEHP) and Dibutyl Phthalate (DBP) which could harm children's health were significantly higher in the Group A household than those in that of Group B. Cladosporium, Aspergillus and Penicillium in indoor air and house dust which could have lead to children's allergy and respiratory diseases correlated with the seasonal climate variation. It was found that high-level indoor PM2.5, TVOCs, DEHP and DBP in house dust were possibly the main risk factors for children's health, with Cladosporium, Aspergillus and Penicillium possibly providing associated health risks.

Indoor Air Pollution Levels in Decorated Residences and Public Places over Xi’an, China

To investigate the indoor air quality (IAQ) over Xi’an, the concentrations of volatile organic compounds (VOCs, including formaldehyde, benzene, toluene, o-xylene, p-xylene, n-butyl acetate, ethylbenzene, styrene, n-undecane, and total VOCs) in 471 residential rooms and 58 public rooms during 2014-2015 were determined. All the data were measured at a variety of 6-48 months after the decorations of these rooms. The results showed that formaldehyde was the most serious pollutant in almost all the monitored rooms. The concentrations of formaldehyde in residences and public places ranged from 0.02 mg m^(-3) to 0.45 mg m^(-3) and 0.05 mg m^(-3) to 0.32 mg m^(-3), respectively. And the concentration levels in the 83.6% selected residences and 44.8% public places exceeded the Chinese National Indoor Air Quality Standard (GB/T 18883-2002) of formaldehyde value (0.1 mg m^(-3)). However, the TVOC concentrations in most sites were lower than the Chinese National Standard (GB/T 18883-2002) value. In residences, the formaldehyde and TVOC concentrations in bedrooms were slightly higher than those in living rooms and other rooms. The relationships among formaldehyde and TVOC concentrations with indoor temperature, relative humidity (RH), and decorative materials (curtain, wall decoration, wood floor, and panel furniture) were also investigated. Formaldehyde levels showed strong positive correlation with indoor temperature and RH. However, the TVOC levels had a relatively weak correlation with indoor air temperature and RH. The wall decoration and panel furniture were the main sources of indoor formaldehyde, while wood floor and panel furniture were the main sources of TVOC. In addition, indoor air pollution of three selected newly decorated houses with 11 rooms was monitored monthly for one year to evaluate the relationship between indoor pollution levels and ventilation time. It was found that the concentrations of formaldehyde and TVOC decreased with ventilation time, and the duration was one year after decoration especially after summer ventilation.

Air Change Rates in Residential Buildings in Tianjin, China

Air change rate is an important factor in indoor environment with regards to occupants’ health. In order to study the association of air change rate in homes and building characteristics, a large scale air change rate measurements were carried out during Sept. 2013-Jan. 2016 in Tianjin, China. 410 homes were investigated and indoor environment were measured. Carbon dioxide concentration in homes was continuously measured for 24 hours. Air change rate was calculated by using CO2 produced by occupants as tracer gas. In the whole home, air change rates during sleeping time averaged 0.61±1.05 h-1 (median=0.32 h-1, n=340). In the bedrooms, air change rate during sleeping time were substantially higher, averaging 0.81±1.33 h-1 (median=0.43 h-1, n=390). Months trends of whole home and bedroom air change rates differed. Air change rates were higher in smaller homes. Formaldehyde and TVOC concentration in homes with higher air change rate were lower.

Tvocs Concentration Status and its Correlation with Ozone Concentration in different seasons at GGU campus, Bilaspur (C.G.) India

It is well documented that Volatile organic compounds (VOCs) are determined to be a risk factor in different environments, with the largest source of its emission being the vehicles. This study represents the temporal variability of Total Volatile Organic Compounds Concentration (TVOC) and Ozone at the different locations of the Guru Ghasidas University, Bilaspur (C.G.) India. Eight locations having different vehicular load in the university campus were selected to generate a database of TVOCs and Ozone concentration in different seasons respectively. The TVOC and Ozone concentration were measured by Phocheck Tiger and Multi Gas Monitor. The obtained data shows that the concentration of TVOC and ozone were found maximum in the summer season and lowest in the winter season at all sites. The site with higher vehicular load (Site-1) record a high concentration of TVOC and Ozone in all the seasons. In contrast, tree cover and vegetation directly reduces the TVOC concentration by lowering the atmospheric temperature and consequently lowers the ozone concentration. The overall data depicts a strong positive significant correlation between TVOC and Ozone. More attention needs to be paid to the places I urban areas where the vehicular load is high, for general welfare of the people, and these sensitive places should be brought under green cover to reduce risk factor caused by TVOCs

Effect of Meteorological Variables on Air Pollutants Variation in Arid Climates

Air quality and climatic factors are closely linked through atmospheric chemical reactions and dynamic processes. This work based on a study conducted over an area of industrial plant located in Saudi Arabia during three consecutive weeks with noticeable varying meteorological parameters in the last week of survey with the main objective to examine the role of climatic factors on differences in air pollutant concentration. A systematic analysis of air pollutants including TVOC, CO, SO2, NO2, and O3 and meteorological parameters including temperature, wind speed (WS), and relative humanity (RH) was conducted for a continuous period of 3 weeks from March to mid-April 2015. Acquired results indicate most of observed key air pollutants increase with increase in relative humidity, except NO2, which experiences a decrease in concentrations simultaneous with increasing relative humidity. This survey study suggests that concentrations of TVOC concentrations increase by 201%, CO by 15.2%, SO2 by 21.6% and ozone by 16% as a direct contribution to relative humidity change. While NO2 experiences a decrease by 53.4% as a result of increase in relative humidity. Ozone exhibits only slightly spatial variation due to sudden change of meteorological variables.

Characterization of odorous compounds and odor load in indoor air of modern complex MBT facilities

Gaseous emissions and chemical compounds responsible for odor nuisance are the most common social concerns arising from modern municipal mechanical-biological waste treatment (MBT) facilities. Regarding to this, an inventory of indoor concentrations of hydrogen sulfide and volatile organic compounds (VOCs) along with odor analyses were carried out at three different full-scale MBT facilities. 48-h profiles of total volatile organic compounds (tVOCs) and hydrogen sulfide were performed in selected areas (reception warehouse, pretreatment, anaerobic digestion and composting areas) and a complete gases and odor characterization were performed at two selected moments of the day according to maximum and minimum tVOCs concentrations, which corresponded to day/night variations. Terpenoids, aromatic hydrocarbons and aliphatic hydrocarbons were the families of VOCs more often detected. The average percentage of contribution of these three VOCs families was 32, 21 and 24%, respectively, while the average percentage of contribution of other VOCs families ranged from 0.2 to 5.5%. A multiple regression method was developed as a simple tool for odor modeling and prediction, showing that 98.5% (p<0.001) of the variance in odor concentration could be explained by the concentrations of hydrogen sulfide and tVOCs. Results obtained suggested that optimization of indoor ventilation systems and, concomitantly, operational costs of MBT facilities was possible in certain locations where ventilation could be reduced up to 20–25% during night hours.

Management of Peat Fires on Smoldering Phase (Case Study: District Siak and District Kampar Riau Province)

The difficulty of finding land for farming activities in Indonesia caused some communities began to switch utilizing peat land for agricultural areas such as oil palm. Oil palm plantation is a commodity that has been developed in Indonesia.Oil palm planted area has increased rapidly.Since 1967 extensive oil palm plantations has increased 35times to 5.6 million ha in 2005 and about 7.8 million ha in 2009. The biggest expansion of oil palm plantations occur in 6 province,one of them is Riau.Most people take a practical way to open agricultural areas by burning peat.Riau Province in Indonesia is one of the major hotspots for peat fires during the dry season. Peat fire at smouldering phaseemits a lot of compounds that are not completely oxidized (e.g. CO, VOCs, PAHs) that more dangerous than the emissions released during combustion at flaming fires. Particulate Matter (PM 2.5 ) is one of the emissions from peat fires too.However, existing data on VOCs and PM 2.5 of smoke from peat fires Indonesia is still limited.The aim of this study was to analyze the concentration of VOCs and PM 2.5 on emissions from peat fires in the Langkai Village Siak District and RimboPanjang Village Kampar District Riau Province when compared with background site and the permissible exposure limit and provide recommendations based on the results of this research.VOCs measurement method is based on NIOSH 1500 and EPA TO-17 while the PM 2.5 based on IMPROVE A method. The average concentration of PM 2.5 is 996.72 ± 531.01μg/m 3 . PM 2.5 concentrations increased (compared with the background site) was very high at 4,838%.This condition causes a decrease in air quality and serious health problems. While the results of the maximum TVOCs concentration obtained in Siak District was 391,880 g/m 3 , while in Kampar Districtwas 195,940 g/m 3 . TVOCs concentration atSiak Districtwas 130.63 times greater than the existing quality standards, while at Kampar District regency was 65.31 times.Environmental improvement recommendations based on the results of this research were buffer zone areadesign to reduce air pollution as a result of peat fires and sealing the ditchs to prevent the spread of fires. Normal 0 false false false EN-US X-NONE X-NONE

Investigation of indoor air quality in shopping malls during summer in Western China using subjective survey and field measurement

Thermal parameters and concentrations of CO2, TVOC and formaldehyde were monitored in shopping malls in four western cities in China during summer. Simultaneously, questionnaire subjective surveys were carried out to investigate the indoor perception of air quality and Sick Building Syndrome (SBS) among staffs in the shopping malls. It was found that stuffy odor had significant correlation with the overall odors perception and staff in the shopping malls had noticeable SBS. Instrument measurement showed that mall C had higher pollution levels of TVOC, while formaldehyde concentrations were higher in mall X and L. Pollution level in the malls is influenced by many factors, and three factors (customer density, ventilation conditions, emission characteristic of merchandise) were discussed in the analysis of data from the four malls. For customer density, the concentrations of CO2 on weekends were higher than on weekdays. Daily CO2 concentration was positively correlated with customer flow rate, but there was no significant strong correlation between customer flow rate and TVOC/formaldehyde concentrations. Underground floors had poorer indoor air quality than over-ground because of lack of fresh air. As for the merchandise sections, the formaldehyde in the home textile section in mall X reached 1.15 mg/m3 with an over standard rate of 83.3% due to the new merchandise added. This paper makes a contribution to knowledge relating to the reasons for discomfort in shopping malls by contributing multiple investigations on contaminants together with information on human perception and the operation of air conditioning systems within the stores.

Long-term indoor gas pollutant monitor of new dormitories with natural ventilation

New furniture and wood-based decoration are the major sources of gas pollutant in indoor environments. Ventilation is the most straightforward approach to eliminate the indoor gaseous pollution. There were many studies investigating the VOC emission characteristics of various building materials, but people still can’t answer the question that how long should we ventilate for an acceptable indoor concentration level in the real life. This study monitors the long-term gas pollutant concentration of 14 new student dormitory rooms with newly furnitured beds, desks and closets. The formaldehyde, TVOC, and ammonia concentrations were measured, the concentration of detected composition of VOCs was listed, and the decay rate under natural ventilation was analyzed. To determine the natural ventilation rate, the traditional tracer gas method and fast VOC decay method were compared, then a quick ventilation rate method was proposed. The VOC emission rate from the furniture was also measured at different times during the whole testing period. As the field measurement has many un-controlled factors, a small single room model was built and furnitured with corresponding loading amount of furniture board materials. The influence of furniture density, supplier and room location on VOC emission rates was also analyzed.

Thermal and environmental conditions in Shanghai households: Risk factors for childhood health

An overall investigation of children’s health status, residential thermal environment, and pollutants was conducted in the homes primary school children during winter and summer in Shanghai, China. The houses were divided into Group A (unhealthy child living) and Group B (healthy child living). During a two-week monitoring period in winter, indoor temperatures in Group A were significantly lower than in Group B (1–2 °C; p < 0.001). Relative humidity (RH) of Group A were 5–8% higher than Group B (p < 0.001), and the ratio of RH > 70% of Group A was around 0.6 in winter. Bad thermal environment in Group A was a risk factor for children’s health. Average winter CO2 concentrations were 758 ppm in Group A and 701 ppm in Group B, and the houses had poor ventilation during nighttime. Indoor concentrations of formaldehyde (HCHO), acetaldehyde and TVOC generally satisfied the Chinese national standards. However, indoor PM2.5 and PM10 concentrations in Group A were higher than those of Group B, and PM concentrations in all investigated houses exceeded the Chinese national standards in winter. Dibutyl phthalate (DBP) and Di (2-ethylhexyl) phthalate (DEHP) in house dust of four living rooms showed very high concentrations (3–4 times the EU recommended limit of 1000 μg/g). Aspergillus and Cladosporium in room air and house dust were linked to high RH, and could be suspected association with poor children’s health. This study provides comprehensive information on indoor thermal and environmental conditions in houses in Shanghai, and their exposures of primary schoolchildren to these health risks.