Outdoor Emission Sources Research Articles

Effect of indoor and outdoor emission sources on the chemical compositions of PM2.5 and PM0.1 in residential and school buildings

Effect of indoor and outdoor emission sources on the chemical compositions of PM2.5 and PM0.1 in residential and school buildings

Emission and environmental distribution of decabromodiphenyl ethane (DBDPE) in China from 2006 to 2026: Retrospection, forecasting, and implications for assessment and management

Decabromodiphenyl ethane (DBDPE) is the main alternative to decabromodiphenyl ether (deca-BDE) in commercial use. However, there is increasing evidence show that DBDPE is a potential persistent organic pollutant, and it has been found ubiquitously in environmental media across China in recent years. Monitoring studies have not been able to determine the overall levels and temporal trends of DBDPE contamination in China, and have been unable to explain how emission patterns can affect their environmental distribution. Therefore, this study estimated the temporal variance of DBDPE emissions and environmental concentrations in five regions of China from 2006 to 2026 using the PROduction-To-EXposure (PROTEX) mass balance model. The results showed that Guangdong Province was the greatest DBDPE pollution hotspot in China due to emissions from plastics manufacturing and e-waste disposal; there was also severe pollution in Shandong Province, where almost all the DBDPE in China is produced. The DBDPE concentrations in indoor and outdoor environments increased substantially in all regions during 2006–2021. Furthermore, in Guangdong Province and Shandong Province, the ratio of indoor/outdoor air concentrations was greater than or close to 1, indicative of significant outdoor emission sources of DBDPE. In contrast, the ratios for the Beijing–Tianjin–Hebei region, East China, and Southwest China were below 1 due to the indoor use of electronic equipment containing DBDPE. The temporal trends of these ratios indicated that DBDPE contamination has gradually spread from high-concentration environments with strong emission sources to low-concentration environments. The outcomes of this study have important implications for the risk assessment of DBDPE use in China and can be used to establish contamination-mitigation actions.

Preschool children health impacts from indoor exposure to PM2.5 and metals.

To better understand the relation between children health and indoor air quality, we measured the concentrations of fine particulate matter (PM2.5) and 11 metals (arsenic, cadmium, chromium, copper, iron, manganese, nickel, lead, antimony, selenium, and zinc) from air samples taken during both winter and spring, and focused on urban and rural area kindergartens of the Upper Silesia Region, Poland, typified by the use of fossil fuels for power and heat purposes. We combined related inhalation intake estimates for children and health effects using separate dose-response approaches for PM2.5 and metals. Results show that impacts on children from exposure to PM2.5 was 7.5min/yr, corresponding to 14 μDALY/yr (DALY: disability-adjusted life years) with 95% confidence interval (CI): 0.3-164min/yr, which is approximately 10 times lower than cumulative impacts from exposure to the metal components in the PM2.5 fraction of indoor air (median 76min/yr; CI: 0.2-4.5×103 min/yr). Highest metal-related health impacts were caused by exposure to hexavalent chromium. The average combined cancer and non-cancer effects for hexavalent chromium were 55min/yr, corresponding to 104 μDALY/yr, with CI: 0.5 to 8.0×104 min/yr. Health impacts on children varied by season and across urban and rural sites, both as functions of varying PM2.5 metal compositions influenced by indoor and outdoor emission sources. Our study demonstrates the need to consider indoor environments for evaluating health impacts of children, and can assist decision makers to focus on relevant impact reduction and indoor air quality improvement.

Indoor and Outdoor PM10-Bound PAHs in an Urban Environment. Similarity of Mixtures and Source Attribution.

Given that the European Union lays down air quality objectives associated with outdoor environments, indoor air mixtures' study acquires a remarkable relevance. This work aims to submit a stepwise methodological framework for assessing similarities between indoor and outdoor air mixtures and apportioning potential emission sources. For reaching this goal, PM10 particles were systematically and simultaneously collected at an indoor (dominant emission sources free) and outdoor environment during a year to determine the PAH content in both air mixtures. Broadly, outdoor PAHs levels were higher than at the indoor location, supporting a strong association between both mixtures (r = 0.968, p > 0.001), mainly during the cold period (r = 0.896, p > 0.001). The light molecular weight PAHs were highlighted at the indoor site, in particular to naphthalene and anthracene. Outdoor emission sources influenced the indoor PAH levels, especially high and medium molecular weight PAHs. The local-traffic load was identified as a dominant pollution source responsible for more than half PAHs determined at both environments. Therefore, the control of outdoor emission sources would be translated into an improvement of indoor air quality.

Distribution, sources and health risk of PAHs in urban air-conditioning dust from Hefei, East China.

In recent decades, indoor air quality (IAQ) has become one of the most important human health issues. The potential properties and potential health hazards of polycyclic aromatic hydrocarbons (PAHs) are associated with their long-term residues, bioaccumulation and semivolatility, and they can also be transferred through a variety of media, such as the atmosphere, water and soil. Dust particles from indoor and outdoor emission sources adhere to A-C filters and can represent air quality to a certain extent. However, few studies have focused on PAHs in A-C filter dust in Hefei, China. In this study, 16 PAHs were selected, dust samples were collected from A-C filters from three different functional districts, and GC-MS analysis of the samples was performed. The concentration of the ∑16PAHs ranged from 7.34 to 326.84μgg-1, 5.07-15.34μgg-1, 4.09-47.26μgg-1 and 0.97-13.38μgg-1 in dust samples from the Administrative District (AD), Industrial District (ID), Commercial District (CD) and Outdoors (OD), respectively. The total PAH concentration in A-C dust was much higher than that in dust deposited outdoors in the urban area. The percentage of 5-6 ring PAHs accounted for more than 70% of the ∑16PAHs, which shows that the PAHs in A-C dust mainly come from pyrolysis rather than a diagenetic source. Principal component analysis (PCA) and diagnostic ratios were used in a source analysis, and the results indicated that the main PAHs emission sources in the different functional districts were coal, wood and biomass combustion. The incremental lifetime cancer risk (ILCR) values indicated a medium to high potential carcinogenic risk for adults and children exposed to dust with PAHs. Particularly, skin contact and ingestion of carcinogenic PAHs from dust are the major exposure pathways and present an exposure risk that is four to five orders of magnitude higher than the risk of inhalation.

Brominated flame retardants (BFRs) in indoor and outdoor air in a community in Guangzhou, a megacity of southern China

Indoor environments contribute a significant portion of human exposure to brominated flame retardants (BFRs) because of their extensive use in various household products. This study investigates the occurrence of a number of BFRs in the indoor and outdoor air in a megacity in southern China, in which little information on indoor BFRs contamination is available. The estimated total PBDE concentrations ranged from 1.43 to 57 pg/m3 indoors and from 1.21 to 1522 pg/m3 outdoors. The indoor concentrations of lower brominated PBDEs that are mainly derived from the technical penta- and octa-BDE mixtures were higher than or comparable to the outdoors, while the indoor levels of DecaBDEs and decabromodiphenyl ethane (DBDPE) were apparently lower than the outdoors. The seasonal variations of BFR concentrations indicated that evaporation from old indoor products is the primary source of Penta- and OctaBDEs in the air, whereas most DecaBDEs and DBDPE concentrations showing weak temperature-dependence are largely released from industrial activities. The PBDE congener profiles in the air were generally similar, which were dominated by BDE209, 28, and 47; whereas the appreciable indoor–outdoor differences in the compositions are possibly due to emission sources, photochemical degradation, or congener-specific transport of BFRs in the indoor and outdoor air. Significant correlations between the indoor and outdoor BFRs were observed suggesting the exchange of BFRs between the two compartments, which are more noticeable for PentaBDEs and DecaBDEs with strong indoor and outdoor emission sources, respectively. This study provides significant insights into the sources of BFRs in urban air in China.

Exploratory study of the indoor and outdoor relationships and chemical compositions of particulate matter in urban households in Colombo

Air pollution associated with emissions of fine particulates (PM10 and PM2.5) is becoming acute, especially in the urban environments of Sri Lanka during the last decade. Recent air quality data obtained from the monitoring stations located in Colombo Fort revealed that the average annual ambient PM10 concentrations in Colombo ranged between 72 and 82 µg/m3, exceeding the national ambient air quality PM10 standard of 50 µg/m3 and WHO air quality guideline of 20 µg/m3. This paper presents the chemical compositions of indoor and outdoor PM10 at selected locations in Colombo, Sri Lanka. Twelve-hour indoor/outdoor PM10 were collected simultaneously from six naturally ventilated roadside households from 13 March to 27 April 2010. Chemical compositions were obtained by using thermal optical reflectance method for carbonaceous compounds and ion chromatography method for water-soluble ions. The results show that indoor micro-environments were significantly affected by the infiltration of outdoor air in Sri Lanka, revealing that outdoor emission sources have significant effects on the indoor air quality. This study provides valuable information on chemical profile of particulates in Colombo which will definitely contribute to the formulation of environmental policy, especially on air pollution control in the future.

Determinants of polycyclic aromatic hydrocarbon levels in house dust

Estimation of human exposures to polycyclic aromatic hydrocarbons (PAHs) is often desired for the epidemiological studies of cancer. One way to obtain information about indoor levels of PAHs is to measure these chemicals in house dust. In this study, we evaluated the predictive value of self-reported and geographic data for estimating measured levels of nine PAHs in house dust from 583 households in the Northern California Childhood Leukemia Study (NCCLS). Using multivariable linear regression models, we evaluated the effects on house-dust PAH concentrations from the following covariates: residential heating sources, smoking habits, house characteristics, and outdoor emission sources. House dust was collected from 2001 to 2007, using both high-volume surface samplers and household vacuum cleaners, and was analyzed for nine PAHs using gas chromatography-mass spectrometry. All nine PAHs were detected in more than 93% of dust samples, with median concentrations ranging from 14 to 94 ng/g dust. Statistically significant effects on PAH concentrations in house dust were found for gas heating, outdoor PAH concentrations, and residence age. Yet, the optimal regression model only explained 15% of the variation in PAH levels in house dust. As self-reported data and outdoor PAH sources were only marginally predictive of observed PAH levels, we recommend that PAH concentrations be measured directly in dust samples for use in epidemiological studies.

VOCs in industrial, urban and suburban neighborhoods, Part 1: Indoor and outdoor concentrations, variation, and risk drivers

Information regarding indoor and ambient concentrations and exposures of volatile organic compounds (VOCs) is limited in terms of the number and types of compounds measured, the spatial and temporal variation of concentrations, and the significance of indoor and outdoor emission sources. This study characterizes a wide range of VOCs across three communities that represent a gradient of population density and industrial activity. Monitoring was conducted in two seasons inside and outside of 159 residences in industrial, urban and suburban cities located in southeast Michigan, USA. Passive samplers were deployed at each location, and analyzed for 98 compounds. Outdoors, 46 different VOCs were detected. Benzene, toluene, p, m-xylene and carbon tetrachloride had the highest concentrations (medians from 1 to 2 μg m −3). Concentrations were elevated in winter in the suburban community, and levels were the highest in the industrial community. Indoors, 53 VOCs were detected, and benzene, toluene, p, m-xylene, n-heptane, α-pinene and d-limonene had the highest concentrations (medians from 1 to 17 μg m −3). Seasonal changes were small or inconsistent. Median indoor levels among the three communities generally followed outdoor rankings. Indoor/outdoor ratios varied from 1 to 10 for most compounds, but up to 100 for several compounds, e.g., d-limonene. Over a quarter of residences had benzene, naphthalene, chloroform and carbon tetrachloride at levels giving a chronic lifetime cancer risk above 10 −5 and sometimes much higher; outdoors, these compounds gave risks exceeding 10 −6. The study identifies a number of indoor emission sources associated with specific and sometimes very high VOC exposures, reports on several VOCs that have not been measured in previous indoor and outdoor studies, and shows the importance of both indoor and outdoor sources. Measured concentrations were at an intermediate level with respect to recent measurements elsewhere in the US, suggesting that study results are broadly representative.

Hospital indoor PM10/PM2.5 and associated trace elements in Guangzhou, China

PM10 and PM2.5 samples were collected in the indoor environments of four hospitals and their adjacent outdoor environments in Guangzhou, China during the summertime. The concentrations of 18 target elements in particles were also quantified. The results showed that indoor PM2.5 levels with an average of 99 μg m − 3 were significantly higher than outdoor PM2.5 standard of 65 μg m − 3 recommended by USEPA [United States Environmental Protection Agency. Office of Air and Radiation, Office of Air Quality Planning and Standards, Fact Sheet. EPA's Revised Particulate Matter Standards, 17, July 1997] and PM2.5 constituted a large fraction of indoor respirable particles (PM10) by an average of 78% in four hospitals. High correlation between PM2.5 and PM10 ( R 2 of 0.87 for indoors and 0.90 for outdoors) suggested that PM2.5 and PM10 came from similar particulate emission sources. The indoor particulate levels were correlated with the corresponding outdoors ( R 2 of 0.78 for PM2.5 and 0.67 for PM10), demonstrating that outdoor infiltration could lead to direct transportation into indoors. In addition to outdoor infiltration, human activities and ventilation types could also influence indoor particulate levels in four hospitals. Total target elements accounted for 3.18–5.56% of PM2.5 and 4.38–9.20% of PM10 by mass, respectively. Na, Al, Ca, Fe, Mg, Mn and Ti were found in the coarse particles, while K, V, Cr, Ni, Cu, Zn, Cd, Sn, Pb, As and Se existed more in the fine particles. The average indoor concentrations of total elements were lower than those measured outdoors, suggesting that indoor elements originated mainly from outdoor emission sources. Enrichment factors (EF) for trace element were calculated to show that elements of anthropogenic origins (Zn, Pb, As, Se, V, Ni, Cu and Cd) were highly enriched with respect to crustal composition (Al, Fe, Ca, Ti and Mn). Factor analysis was used to identify possible pollution source-types, namely street dust, road traffic and combustion processes.

Road traffic, NO<SUB align=right>2 exposure and respiratory function among children (VESTA study)

Within the multicentre VESTA case-control study on childhood asthma and traffic air pollution, we studied the association between the respiratory function and NO2 personal exposures or intensity of traffic close to homes and schools. The relative contribution of different indoor and outdoor emission sources on personal NO2 exposures was also assessed. The respiratory function (forced expiratory volume in one second - FEV1 - and peak expiratory flow rate - PEFR) was measured with a One-Flow tester R. NO2 personal exposure was measured using passive Ogawa samplers that were worn during 48 hours by study participants, aged four to 14 years old. Exposure to traffic exhausts was assessed through an index based on a time-weighted average of traffic density to road distance ratios. The most influential variables that predicted NO2 personal exposures were the traffic index, use of a gas cooker at home and background ambient air pollution, with variable associations across cities (model R2 rank from 0.33 to 0.67). No association was found between the respiratory function and the levels of NO2 personal exposure; FEV1 or PEFR values, however, were associated with the traffic index, in two out of four cities. These results suggest that cumulative exposure to traffic exhausts may alter the respiratory function of children.