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In this research, enrichment factor (EF) and pollution load index (PLI) were utilized to explore the contamination characteristics of toxic elements (TEs). The results exhibited that the study area was mainly moderately polluted, and the EF values of Cd, Zn, Pb, Cu and Sb were all > 1, which were cumulative. The concentrations of Cr, Cu, Zn and Pb increased with the decrease of dust particle size. The investigation results of chemical speciation and bioavailability of TEs showed that Zn had the highest bioavailability. Three sources of TEs were determined by positive matrix factorization (PMF), Pearson correlation analysis and geostatistical analyst, comprising factor 1 mixed sources of industrial and transportation activities (46.62%), factor 2 natural source (25.56%) and factor 3 mixed source of agricultural activities and the aging of park infrastructures (27.82%). Potential ecological risk (PER) and human health risk (HHR) based on PMF model were exploited to estimate PER and HHR of TEs from different sources. The PER value of TE in the park dust was 114, indicating that ecological risk in the study area was relatively high. Factor 1 contributed the most to PER, and the pollution of Cd was the most serious. There were no significant carcinogenic and non-carcinogenic risks for children and adults in the study area. And factor 3 was the biggest source of non-carcinogenic risk, As, Cr and Pb were the chief contributor to non-carcinogenic risk. The primary source of carcinogenic risk was factor 2, Cr was the cardinal cancer risk element.

Large-scale smelting activities release large amounts of potentially toxic elements (PTEs) in fine particles. These particles floating in the air eventually settle on leaves, roads, and even indoors. In smelting areas, indoor environments are generally considered relatively safe. However, these areas are not taken seriously and need to be assessed. This paper systematically studied pollution characteristics, main sources and health risks of ten potentially toxic elements, PTEs (Mn, Ni, Cu, Zn, Hg, Cd, As, Cr, Pb, and Tl), of dust samples from different indoor environments in smelting areas using various methods. Therefore, this study analyzed dust samples from 35 indoor environments. The enrichment factors showed that the indoor dust samples were extremely enriched by Cd and Cu and significantly enriched by Hg, Pb, As, and Zn. The result of the spatial distribution showed that the high-value PTEs were mainly distributed near the Cu smeltery. Three sources were quantitatively assigned for these PTEs, and they were industrial smelting and traffic activities (44.40%), coal-fired activities (18.11%), and natural existence (37.49%). Based on the calculation of health risk, the value of THI for children was 7.57, indicating a significant non-carcinogenic risk. For carcinogenic risk, the values of TCR for children and adults were 2.91×10−2 and 2.97×10−3, respectively, which were much higher than the acceptable risk value 1×10−4. Combining health risk assessment with source discrimination, we found that the industrial discharges and traffic activities were the most main source of non-cancer and cancer risks. Therefore, smelting activities should be more strictly monitored, and traffic emission management should be strengthened.

The residential sector is a major source of air pollutant emission inventory uncertainties. A nationwide field emission measurement campaign was conducted in rural China to evaluate the variabilities of realistic emission factors (EFs) from indoor solid fuel combustion. For a total of 1313 burning events, the overall average EFs (±standard deviation) of PM2.5 were 8.93 ± 6.95 and 7.33 ± 9.01 g/kg for biomass and coals, respectively, and 89.3 ± 51.2 and 114 ± 87 g/kg for CO. Higher EFs were found from burning of uncompressed straws, while lower EFs were found from processed biomass pellets, coal briquettes, and relatively clean anthracite coals. Modified combustion efficiency was found to be the most significant factor associated with variations in CO EFs, whereas for PM2.5, fuel and stove differences determined its variations. Weak correlations between PM2.5 and CO indicated high uncertainties in using CO as a surrogate for PM2.5. EFs accurately fit log-normal distributions, and obvious spatial heterogeneity was observed attributed to different fuel-stove combinations across the country. Emission estimation variabilities, which are determined by the interquartile ranges divided by the median values, were notably reduced when spatially resolved EFs were adopted in the inventory.

Based on the tropical cyclone track data in the northwest Pacific Ocean from 2015 to 2020, meteorological observation data, and ozone concentration monitoring data in the Pearl River Delta (PRD), the impacts of four tropical cyclones, namely the westbound tropical cyclone (type A), East China Sea tropical cyclone (type B), offshore tropical cyclone (type C), and offshore tropical cyclone (type D), on ozone concentration in the PRD were analyzed. The results showed that:under the influence of the type A tropical cyclone, the risk of regional ozone concentration exceeding the standard exhibited little change. Under the influence of the type B tropical cyclone, the risk of ozone exceeding the standard in the PRD was obviously increased. Under the influence of the type C tropical cyclone, the risk of regional ozone exceeding the standard obviously increased, but the increase was weaker than that of the type B tropical cyclone. The type D tropical cyclone was far away from the Chinese mainland and had little influence on ozone concentration in the PRD. When the type A or type C tropical cyclones occurred, the average daily maximum 8-hour average ozone concentration (MDA8) in the PRD region increased by approximately 5 μg·m

A volatile organic compounds(VOCs) emission source classification and accounting system from domestic sources in China was established for the period between 2010 and 2018. Suggestions for the prevention and treatment of VOCs from domestic sources were developed and proposed. The results showed that the total VOCs emission inventory from domestic sources in China in 2018 was 2518 kt. Architectural decoration, asphalt road paving, cooking, and rural household biomass use source were the four largest contributors, accounting for 69.22% of the total emissions. Chemical household products and urban and rural coal use contributed equally, accounting for 10.43% and 9.98%, respectively, whilst car repair accounted for 7.75%. Shandong, Sichuan, Henan, Guangdong, Jiangsu, and Hebei were the six provinces that contributed the most(36.01%). During the 2010-2018 period, China's domestic VOCs emissions increased at a rate of 0.43%, and after reaching a peak in 2013, the emissions began to decline at a rate of 2.23%. The reason for the decline was that, on the one hand, the cleaner energy consumption of residents made a contribution to the gradual reduction of domestic coal and biomass consumption. On the other hand, the gradual saturation of housing construction in some areas, which led to a decrease in the annual construction of the country. It is recommended to promote the comprehensive management of architectural decoration, cooking methods, and car repair, while paying attention to the VOCs emissions from asphalt road paving. Meanwhile, continue to optimize the energy use structure of domestic sources, and promote the pollution control of civil coal and household biomass combustion in accordance with local regulations and multiple measures.

In this research, enrichment factor (EF) and pollution load index (PLI) were utilized to estimate the features of enrichment and contamination of PTEs in farmland soil. Furthermore, combining the spatial distribution characteristics of potentially toxic elements (PTEs) and positive matrix factorization (PMF) to distinguish and quantify the sources of PTEs in farmland soil, and then the potential ecological risk (PER) and human health risk (HHR) model based on PMF are applied to quantify the ecological and human health risks from different sources. Taking Puning District as an example, four sources of PTEs in farmland soil were quantitatively allocated. For ecological risk, the study area is at moderate ecological hazard level, and industrial activities were the greatest contributor. The mean E_r^i of Hg were 69.82, reaching medium ecological risk level. For human health risks, both adults and children have no evident non-carcinogenic risk in the study area. And natural source was the largest contributor to non-carcinogenic risk, followed by agricultural activities. With regard to carcinogenic risk, tolerable risks of soil PTEs in the study area were limited not only for adults but also for children. Furthermore, compared with adults, the health risks of children, whether non-carcinogenic or carcinogenic, were higher than those of adults, and the trends in health risks for children and adults were similar. A comprehensive scheme combining source contribution and risk assessment is conducive to quantitatively assess ecological risks, health risks and priority pollution sources, thereupon provide effective suggestions for protecting human health and preventing and controlling pollution.

Non-ferrous metal smelting activities have always been considered as one of the foremost anthropogenic sources of potentially toxic elements (PTEs). The enrichment factor (EF) and pollution load index (PLI) were used to evaluate the pollution level of soil PTEs; positive matrix factorization (PMF), correlation analysis, and geostatistics were utilized to quantify the sources of soil PTEs; and potential ecological risk (PER) and human health risk (HHR) of different sources from farmland, construction land, and natural land were quantifiably determined via combined PTE sources with PER and HHR assessment models. Taking the smelting area of Daye City as an example, the evaluation results of EF and PLI showed that the soil PTE pollution in the study area was serious, especially Cd and Cu. And four sources were quantitatively allocated as agricultural practices (12.14%), traffic emissions (23.07%), natural sources (33.46%), and industrial activities (31.33%). For PER, industrial activities were the largest contributor to PER, accounting for 55.66%, 56.30%, and 55.36% of farmland, construction land, and natural land, respectively, and Cd was the most dangerous element. In terms of HHR, industrial activities were also the cardinal contributors under the three land use types. Children were exposed to serious non-carcinogenic risks under three land use patterns and slight carcinogenic risk in construction land (1.06E - 04). Significantly, the carcinogenic risk of children in farmland (9.06 × 10

To grasp the key factors affecting particle mass scattering efficiency (MSE), particle mass and number size distribution, PM2.5 and PM10 and their major chemical compositions, and the particle scattering coefficient (bsp) under dry conditions were measured at an urban site in Guangzhou, southern China, during 2015–2016. On an annual average, 10±2 %, 48±7 % and 42±8 % of PM10 mass were in the condensation, droplet and coarse modes, respectively, with mass mean aerodynamic diameters (MMADs) of 0.78±0.07 in the droplet mode and 4.57±0.42 µm in the coarse mode. The identified chemical species mass concentrations can explain 79±3 %, 82±6 % and 57±6 % of the total particle mass in the condensation, droplet and coarse mode, respectively. Organic matter (OM) and elemental carbon (EC) in the condensation mode, OM, (NH4)2SO4, NH4NO3, and crustal element oxides in the droplet mode, and crustal element oxides, OM, and CaSO4 in the coarse mode, were the dominant chemical species in their respective modes. The measured bsp can be reconstructed to the level of 91±10 % using Mie theory with input of the estimated chemically resolved number concentrations of NaCl, NaNO3, Na2SO4, NH4NO3, (NH4)2SO4, K2SO4, CaSO4, Ca(NO3)2, OM, EC, crustal element oxides and unidentified fraction. MSEs of particle and individual chemical species were underestimated by less than 13 % in any season based on the estimated bsp and chemical species mass concentrations. Seasonal average MSEs varied in the range of 3.5±0.1 to 3.9±0.2 m2 g−1 for fine particles (aerodynamic diameter smaller than 2.1 µm), which was mainly caused by seasonal variations in the mass fractions and MSEs of the dominant chemical species (OM, NH4NO3, (NH4)2SO4) in the droplet mode. MSEs of the dominant chemical species were determined by their lognormal size-distribution parameters, including MMADs and standard deviation (σ) in the droplet mode.

Nonferrous metallurgy is causing significant concerns due to its emissions of heavy metals into environment, degrading environmental quality, and consequently posing high risks to human health. In this study, the concentration levels of Cadmium (Cd), Copper (Cu), Lead (Pb), and Arsenic (As) were investigated in soil, crop, well water, and fish samples collected around the Daye Copper Smelter in Hubei province, China, and the potential health risks were assessed for local children. The results showed that soils near the smelter were heavily polluted by Cd, Cu, Pb, and As, with the mean concentrations of 4.87, 195.26, 92.65, and 35.84 mg/kg, respectively, which were significantly higher than the values of soil Cd (0.18 mg/kg), Cu (32.84 mg/kg), Pb (28.46 mg/kg), and As (13.65 mg/kg) in the reference area (p

Architectural decoration is an important anthropogenic emission source of VOCs in China, and there are few studies on the emission of VOCs from architectural adhesives. In this study, the VOCs content level and emission factors of various architectural adhesives were measured and then, a VOC emission inventory of architectural adhesives in China from 2013 to 2017 was established by a top-down emission factor method. Results showed that the comprehensive VOCs emission factor of architectural adhesives was 97.0 kg·t

Based on the monitoring data of the Guangdong-Hong Kong-Macao Pearl River Delta Regional (PRD) Air Quality Monitoring Network from 2006 to 2019, the ozone trend in RRD was analyzed using the Mann-Kendall test method, Sen's slope method, and the Pettitt change point test. The results show that:① the average ozone concentration in the PRD has increased significantly from 2006 to 2019 (

An industrial volatile organic compounds (VOCs) emission inventory was developed in China in 2018. It was based on the emission factors method, using a revised and updated source classification system and emission factors of key industrial sources. Results showed that the total industrial VOCs emission in China in 2018 reached as high as 12698 kt. Processes using products containing VOCs were the largest contributors, accounting for 59% of the total emission. The industrial coating industry, printing, the basic organic chemical industry, gasoline storage and transport, and the oil refinery industry were the five largest emitters, accounting for 54% of the total emission. Guangdong, Shandong, Zhejiang, and Jiangsu were the four largest emission contributors, contributing to 41% of the total emission. Hainan, Ningxia, Tibet, Heilongjiang, and Xinjiang showed the largest VOCs emission intensities, with more than 80 t·(100 million yuan)

To make pollution evaluation of potentially hazardous elements in the soil more accurately, the regional geochemical baseline concentrations of eight potentially hazardous elements (Cr, Ni, Cu, Zn, As, Cd, Hg, and Pb) were established in Huilai County using cumulative frequency distribution curves. Then, the pollution load index and enrichment factor were applied to estimate the contamination levels, based on these geochemical baseline concentrations. The results suggested that topsoil was moderately polluted by potentially hazardous elements, while Cd pollution in the construction land and As pollution in the farmland was relatively severe. The possible sources of eight potentially hazardous elements were analyzed by correlation analysis, geostatistics and positive matrix factorization. Four sources have been determined and apportioned, namely industrial activities, natural sources, agricultural practices, and traffic emissions. Combining the health risk assessment with the source profiles, the health risks quantified from four sources were estimated under farmland, construction land, and woodland. The results showed that agricultural practices were the most main source of non-cancer and cancer risks under woodland and farmland for adults; industrial activities were the most main source of non-cancer and cancer risks under construction land for adults. Children's health risks, both carcinogenic risk and non-carcinogenic risk, were greater than adults, and the health risk trends of adults and children showed similarities. Therefore, agricultural practices under woodland and farmland should be controlled and managed as a priority, while industrial activities should be given priority to control and management under construction land.

Nitrate has become the most important hydrophilic chemical component in PM2.5 during serious air pollution periods in urban areas of the Pearl River Delta (PRD) region of south China, but there is a lack of fully understanding of its formation mechanisms and controlling factors, especially during daytime nitrate episodes. To fill the knowledge gap, water-soluble inorganic ions in PM2.5 and trace gases including SO2, HNO3, NH3, NOx and O3, particle size distribution, vertical profile of aerosol backscatter density, and ground-level and vertical profiles of key meteorological variables were simultaneously measured at high time resolution in urban Guangzhou of the PRD. The remarkably enhanced nitrate mass concentrations observed at the surface-level during daytime were identified to be caused by strong boundary-layer turbulent mixing of residual aerosols produced from evaporation of low-level shallow stratocumulus clouds. This finding may have important implications on the sources of secondary inorganic aerosols in this and other similar cloudy regions.

Daily PM 2.5 samples were collected at an urban site in Guangzhou in 2014 and at a suburban site in Zhuhai in 2014–2015. Samples were subject to chemical analysis for various chemical components including organic carbon (OC), element carbon (EC), major water-soluble inorganic ions, and trace elements. The annual average PM 2.5 mass concentration was 48 ± 22 μg m − 3 and 45 ± 25 μg m − 3 in Guangzhou and Zhuhai, respectively, with the highest seasonal average concentration in winter and the lowest in summer at both sites. Regional transport of pollutants accompanied with different air mass origins arriving at the two sites and pollution sources in between the two cities caused larger seasonal variations in Zhuhai (> a factor of 3.5) than in Guangzhou ( 2.5 in Guangzhou and Zhuhai, respectively. Ship emissions, a source factor previously ignored in making emission control policies in the Pearl River Delta region of south China, were among the top contributors to PM 2.5 at both sites, accounting for > 17% of PM 2.5 mass concentrations.

A database of refined raw materials and end treatment-based VOCs emission factors for typical solvent use sources was developed for the Pearl River Delta. For this, the impact of composition and the content of raw materials, production process, and comprehensive end treatment on the emission of VOCs was analyzed. The solvent use sources included printing, furniture manufacturing, and electronic component and equipment manufacturing. The results showed that the main VOCs in the raw materials used in printing were ethyl acetate, propyl acetate, isopropanol, propanol, and ethanol, which contributed 60%-80% to the total amount of VOCs. Ethyl acetate and butyl acetate were the main oxygenated VOCs (OVOCs) from the raw materials used in furniture manufacturing, contributing 45%-65% of the total. The main VOCs from the raw materials used in electronic component and equipment manufacturing were OVOCs such as alcohols, ethers and phenols, BTEX, and halohydrocarbons. The uncontrolled and controlled emission factors for VOCs from printing were 415.2 kg·t

Heavy metals (HMs) in soil cause adverse effects on ecosystem and human health. Quantifying ecological risk and human health risk (HHR) from sources can determine priority sources and help to mitigate the risks. In this research, geostatistics and positive matrix factorization (PMF) were used to identify and quantify the sources of soil HMs; and then ecological risk and HHR from different sources under woodland, construction land and farmland were quantitatively calculated by combining the potential ecological risk index (RI) and HHR assessment models with PMF model. Taking Jiedong District as an example, four sources were quantitatively apportioned, which were agricultural practices (23.08%), industrial activities (29.10%), natural source (22.87%) and traffic emissions (24.95%). For ecological risk, industrial activities were the greatest contributor, accounting for about 49.71%, 48.11% and 47.15% under construction land, woodland and farmland, respectively. For non-carcinogenic risk, agricultural practices were the largest source under woodland and farmland, while industrial activities were the largest source under construction land. As for carcinogenic risk, no matter which kind of land use, agricultural practices were the largest source. In addition, the health risks of children, including non-carcinogenic and carcinogenic risks, were higher than those of adults, and the trends in health risks for children and adults were similar. The integrated approach was useful to evaluate ecological risk and HHR quantification from sources under different land use, thereby providing valuable suggestions for reducing pollution and protecting human health from the sources.

Based on ozone monitoring and meteorological data from 2000 to 2015 in Hong Kong, the characteristics of ozone pollution and the influence of meteorological factors on the ozone pollution were analyzed. The results show that:① A seasonal variation of the ozone concentration in Hong Kong is notable:autumnspringwintersummer. Days of ozone exceeding the standard value are concentrated in summer and autumn and rarely occur in winter and spring. ② The annual mean ozone concentration of the maximum daily 8-h average (MDA8) in Hong Kong increases from 2000 to 2015, with an average growth rate of 0.77 μg·(m

Large-scale industrial activities emit large amounts of potentially toxic elements (PTEs) in the form of particulate pollutants. Most of these pollutants settle on the road and eventually mix into the road dust. In the long-term, they will have adverse effects on ecosystems and human health. In this research, various analytical methods were used to assess the pollution characteristics of the 12 PTEs (Mn, Ni, Cu, Zn, Hg, Cd, As, Cr, Pb, Tl, Co, and Sb) in the study area, and geo-statistics served to analyze the spatial distribution characteristics of PTEs. Combining the potential ecological risk method and health risk assessment with positive matrix factorization (PMF) from different sources entailed a quantitative evaluation. Taking a large Cu smelter in central China as an example, three sources were quantitatively apportioned, these being smelting emissions and transportation activities (54.04%), daily human activities and natural existence (33.36%), as well as coal-fired activities of industrial production (12.60%) separately. The results showed that in more than 90% of the samples, Cd, Cu, Hg, Pb, As, Zn, Tl and Sb indicated high levels of contamination. In terms of spatial distribution, the high-value PTEs were mainly distributed near the smelter. Regarding ecological risk, smelting emissions and transportation activities were the greatest source, followed by coal-fired activities. As for human health risk, adults did not have significant non-carcinogenic risk, but children had obvious non-carcinogenic risk. Among different sources, the risk of smelting emissions and transportation activities were the highest. After calculating the value of carcinogenic risks, it emerged there was no obvious carcinogenic risk for children and adults in the study area. The comprehensive approach combining risk assessments with source identification is very effective in identifying prior pollutants and important sources of pollution. They can provide a good theoretical reference for effective prevention and control of pollution.

Seasonal characteristics of PM2.5, organic carbon (OC) and elemental carbon (EC) were studied in Taiyuan from 2009 to 2010. PM2.5 samples were collected by pre-baked quartz filters with high-volume air sampler, and then OC and EC were analyzed by thermal/optical reflectance method. The annual average concentrations of PM2.5, OC and EC were 220.2, 37.4 and 19.6 µg/m3 respectively, which were higher than those in most regions in China. Total carbonaceous aerosol (TCA) accounted for more than one third of the total PM2.5 mass. The levels of PM2.5, OC and EC were the highest in winter, followed by spring, fall and summer. OC and EC were well correlated in summer compared with other seasons, indicating the presence of other additional sources such as biomass burning in fall, coal combustion for heating in winter and dust in spring. Higher OC/EC ratios in winter might be primarily attributed to the significant increase of direct emission of OC as a result of coal and biomass combustion, and also cooling effect of carbonaceous aerosols due to low temperature and stagnated atmospheric condition. These results showed that the pollution of carbonaceous particles in Taiyuan was serious, and might be an inducing factor of dust haze, especially in winter.

A static aeration biopile process was used to bioremediate polycyclic aromatic hydrocarbon (PAH)-contaminated soil using four different approaches for treating about 30 m3 of soil at a former oil-producing site. The four treatments investigated were as follows: (i) fertilizer plus bulking agent (FB); (ii) fertilizer, bulking agent, plus Tween 80 (FBT); (iii) fertilizer, bulking agent, Tween 80, plus fungi agent (FBTF); and (iv) fertilizer, bulking agent, bacterial inoculum, plus fungi agent (FBBF). After bioremediation for 320 days, the total amount of 16 PAHs ranged from 4.14 to 5.31 mg/kg in the final soil, removal rates ranging from 75.5% to 81.5%. The sum concentration of seven carcinogenic PAHs decreased down to 0.15 mg/kg. The values of the total toxicity equivalence concentrations for 16 PAHs ranged from 0.014 to 0.068 mg/kg. The removal rates of the 16 PAHs in these four different treatments decreased in order FBBF > FBT > FBTF > FB.

Total gaseous mercury (TGM) was continuously monitored at Wuzhi mountain (Wuzhishan) using the high-resolution automatic atmospheric mercury vapor analyzer (Tekran 2537B) from May 2011 to May 2012. The annual geometric mean TGM concentration was (1.58 ± 0.71) ng x m(-3), suggesting that the atmosphere was not obviously polluted. The TGM level at WuZhi mountain remained low from June to August in 2011 and from March to May in 2012, while higher values were observed from September in 2011 to January in 2012. Tropical monsoons played an important role in the monthly variation of TGM. TGM concentrations showed a clear diurnal trend with the minimum concentration occurring at 09:00 AM and the peak concentration at 19:00 PM due to the combined impact of the long-range transport of atmospheric mercury and local meteorological conditions. The temporal trend of TGM highlighted the impact of long-range transport from the mainland of China on the distribution of TGM in ambient air at Wuzhi mountain by the results of backward trajectory analysis using HYSPLIT.

According to the local habit of eating fish, in a total of 68 samples, 8 kinds of different trophic levels of edible fish collected in Shanghai were determined in terms of concentration and distribution profile of short chain chlorinated paraffin (SCCPs) in muscles to investigate the pollution status of SCCPs in edible fish from the Yangtze River Delta region. The results indicated that the concentrations (dw) of SCCPs in edible fish were in the range of 36-801 ng x g(-1). With the increase in carbon chain length, the concentration of SCCPs decreased. In addition, lower chlorinated (Cl6-Cl8) and shorter chain (Cl10, C11) congeners were the dominant chlorine and carbon homologues groups, respectively, contributing a total relative abundance of 61.46%-82.50% to the total abundance of SCCPs. The levels of SCCPs in fish of Shanghai were in the medium level worldwide, and the distribution pattern was in line with those of the domestic and foreign studies.

Fifty-two house dust samples were randomly collected in Guangzhou and Haikou City, to analyze the concentrations of Sigma10 PBDEs (sum of BDE 28, 47, 66, 85, 99, 100, 153, 154, 183 and 209), the PBDE composition profiles, and possible influencing factors, and estimate human exposure to PBDEs via dust ingestion for adults and toddlers. The results showed that PBDEs were found in all samples, with the Sigma10 PBDEs concentrations ranging from 544.2 ng/g to 9 654 ng/g, and with median (mean) of 2 547 (3 096) ng/g. The PBDE levels in Guangzhou samples were obviously higher than those in Haikou. No significant correlations between PBDE levels and residential characteristics (number of TVs, computers, and polyurethane foam-contained furniture, time of using TVs and computers) were observed. BDE209, with a mean concentration of 3 021 ng/g, was the dominated congener, contributing 73.70%-99.74% to the Sigma10 PBDEs, with a mean contribution of 96.85%. BDE 47, 99 and 183 were the most abundant congeners of Sigma9 PBDEs (BDE 209 excluded), with a mean contribution of 24.48%, 23.99%, and 21.66%, respectively. There is no notable difference in PBDE composition between Guangzhou and Haikou samples. The estimated exposure for adults and toddlers to PBDEs ranged from 10.59 ng/d to 254.7 ng/d and from 140.1 ng/d to 509.3 ng/d, respectively. Due to their increased dust ingestion rates, toddlers in took more PBDEs via dust ingestion than adults. Dust ingestion was an important human exposure route for PBDEs, especially for toddlers.