Atmospheric VOCs in an industrial coking facility and the surrounding area: Characteristics, spatial distribution and source apportionment.

Industrial coking facilities are an important emission source for volatile organic compounds (VOCs). This study analyzed the atmospheric VOC characteristics within an industrial coking facility and its surrounding environment. Average concentrations of total VOCs (TVOCs) in the surrounding residential activity areas (R1 and R2), the coking facility (CF) and the control area (CA) were determined to be 138.5, 47.8, 550.0, and 15.0 µg/m3, respectively. The cold drum process and coking and quenching areas within the coking facility were identified as the main polluting processes. The spatial variation in VOCs composition was analyzed, showing that VOCs in the coking facility and surrounding areas were mainly dominated by aromatic compounds such as BTX (benzene, toluene, and xylenes) and naphthalene, with concentrations being negatively correlated with the distance from the coking facility (p < 0.01). The sources of VOCs in different functional areas across the monitoring area were analyzed, finding that coking emissions accounted for 73.5%, 33.3% and 27.7% of TVOCs in CF, R1 and R2, respectively. These results demonstrated that coking emissions had a significant impact on VOC concentrations in the areas surrounding coking facility. This study evaluates the spatial variation in exposure to VOCs, providing important information for the influence of VOCs concentration posed by coking facility to surrounding residents and the development of strategies for VOC abatement.

Emission and gas-particle partitioning characteristics of atmospheric halogenated and organophosphorus flame retardants in decabromodiphenyl ethane-manufacturing functional areas.

The emission and gas-particle partitioning characteristics in various functional areas of production lines are still unknown. However, flame-retardant manufacturing activities are the primary emission source of flame retardants. Thus, fine particles and gases were investigated in three functional areas of a decabromodiphenyl ethane production line, i.e., polybrominated diphenyl ethers (PBDEs), novel brominated flame retardants (NBFRs), dechlorane plus (DPs), and organophosphorus flame retardants (OPFRs) in a flame-retardant manufacturing factory. High levels of PBDEs (8.02 × 103-4.16 × 104 pg/m3), NBFRs (6.05 × 103-1.92 × 105 pg/m3), and DPs (89.5-5.20 × 103 pg/m3) were found in various functional areas, suggesting manufacturing activities were a primary emission source. In contrast, OPFRs were derived from long-range transport or other non-industrial sources. Varied concentrations of PBDEs, NBFRs, and DPs were observed in different production lines, higher in the reaction zone area than others. As the predominant compounds, decabromodiphenyl ether, decabromodiphenyl ethane, syn-DP, and tris(chloropropyl) phosphate accounted for 54.7%, 89.3%, 93.4%, and 34.7% of PBDEs, NBFRs, DPs, and OPFRs, respectively. Three models were used to predict the gas-particle partitioning of the halogenated flame retardants emitted from manufacturing activities. The Li-Jia Empirical Model predicted the gas-particle partitioning behavior well. This research shows that the adsorption-desorption process of the halogenated flame retardants between the gaseous and particulate phases did not reach equilibrium.

Underestimated contribution of fugitive emission to VOCs in pharmaceutical industry based on pollution characteristics, odorous activity and health risk assessment.

Fugitive emission has been becoming an important source of volatile organic compounds (VOCs) in pharmaceutical industry, but the exact contribution of fugitive emission remains incompletely understood. In present study, pollution characteristics, odorous activity and health risk of stack and fugitive emissions of VOCs from four functional units (e.g., workshop, sewage treatment station, raw material storage and hazardous waste storage) of three representative pharmaceutical factories were investigated. Workshop was the dominant contributor to VOCs of fugitive emission in comparison with other functional units. Extreme high concentration of VOCs from fugitive emission in unsealed workshop (94.87 mg/m3) was observed relative to sealed one (1.18 mg/m3), accounting for 31% and 5% of total VOCs, respectively. Fugitive emission of VOCs in the unsealed workshop mainly consisted of n-hexane, 1-hexene and dichloromethane. Odorous activity indexes and non-cancer hazard ratios of these VOCs from fugitive emission in the unsealed workshop were as high as that from stack exhaust. Furthermore, cancer risk of dichloromethane from fugitive emission and stack exhaust was up to (1.6-1.8) × 10-5. Odorous activity or health risk index of the VOCs from fugitive emission was up to 13 or 11 times of the corresponding threshold value, posing remarkable health threat on pharmaceutical workers. Our findings highlighted the possibly underestimated contribution of fugitive emission on VOCs in the pharmaceutical industry.

Explication on distribution patterns of volatile organic compounds in petro-chemistry and oil refineries of China using a species-transport model and health risk assessment.

Volatile organic compounds (VOCs) from industrial emissions have attracted great attention due to their negative effects on human, but there is lack of deterministic air quality model for VOC emissions. In this study, airborne VOCs from a typical petrochemical and oil refinery region, Lanzhou, Gansu province of China, were on-site measured. The regional pollution patterns were investigated using a species transport model and the health risks were evaluated. The spatial distribution of VOCs showed that 87.5 % of the airborne VOCs were benzene, toluene, ethylbenzene, and xylene having higher concentration (146 µg/m3) in the north direction oil refinery industrial areas. The concentrations of toluene and benzene were as high as 41.5 and 33.3 µg/m3 in the 4 km2 area away from the petrochemical emission source, respectively, and the concentration of o-/m + p-xylene was up to 79.7 µg/m3. Based on the measured concentration data, the numerical results showed that the accumulation of high concentration of VOC species by mass transfer in the region is related to the atmospheric diffusion driven by downward-moving air over the valley areas. Non-carcinogenic risk assessments showed that airborne benzene exposure had acceptable hazard quotient of 0.185 for adults, which was 1.8 times of children's (0.102), whereas it was found that a high carcinogenic risk (>10-4) from benzene in several sampling sites and diffuse distance become significant for carcinogenic risk. This study verified the effectiveness of VOC atmospheric diffusion model through a large number of on-site monitoring data, providing data support for model-based risk assessment.

Bridged-ozonolysis of mixed aromatic hydrocarbons and organic amines: Inter-inhibited decay rate, altered product yield and synergistic-effect-enhanced secondary organic aerosol formation.

Ozonolysis of aromatic hydrocarbons (AHs) or organic amines (OAs) occurs via different transformation processes, with varying rate constants and contributions to secondary organic aerosol (SOA) formation. However, to date no data is available on the ozonolysis of mixtures of AHs and OAs. This study investigated the kinetics, products and SOA yield from ozonolysis of mixture of trimethylamine with styrene, toluene or m-xylene. In the mixed system, the decay rates of styrene and trimethylamine were (1.32 ± 0.26) × 10-4 s-1 and (0.80 ± 0.02) × 10-4 s-1, decreasing up to 36.5 % and 54.4 % compared with their respective individual systems. This inter-inhibition of decay rates increased the yield of main products from styrene (i.e. benzaldehyde) by 23.5 % and trimethylamine (i.e. nitromethane) by 346.4 %. Ozonolysis of styrene or trimethylamine produced formaldehyde, which acted as a bridged product connecting the ozonolysis pathways of these two substrates, altering the yields of all products. Ozonolysis of styrene to benzaldehyde determined the increase of SOA particle number concentration (from 9.5 × 105 to 1.9 × 106 particles cm-3), while trimethylamine ozonolysis to N, N-dimethylformamide contributed to synergistic-effect-enhanced SOA yield (from (64.3 ± 3.5)% to (68.1 ± 4.8)%). The findings provide a novel insight into the kinetics and mechanism of ozonolysis, as well as the resulting SOA formation from mixtures of AHs and OAs, helping to comprehensively understand the transformation and fate of organics in real atmospheric environments.

A new method of simultaneous determination of atmospheric amines in gaseous and particulate phases by gas chromatography-mass spectrometry.

As more attention is being paid to the characteristics of atmospheric amines, there is also an increasing demand for reliable detection technologies. Herein, a method was developed for simultaneous detection of atmospheric amines in both gaseous and particulate phases using gas chromatography-mass spectrometry (GC-MS). The amine samples were collected with and without phosphoric acid filters, followed by derivatization with benzenesulfonyl chloride under alkaline condition prior to GC-MS analysis. Furthermore, the method was optimized and validated for determining 14 standard amines. The detection limits ranged from 0.0408-0.421 µg/mL (for gaseous samples) and 0.163-1.69 µg/mL (for particulate samples), respectively. The obtained recoveries ranged from 68.8%-180% and the relative standard deviation was less than 30%, indicating high precision and good reliability of the method. Seven amines were simultaneously detected in gaseous and particulate samples in an industrial park using the developed method successfully. Methylamine, dimethylamine and diethylamine together accounted for 76.7% and 75.6% of particulate and gaseous samples, respectively. By comparing the measured and predicted values of gas-particle partition fractions, it was found that absorption process of aqueous phase played a more important role in the gas-partition of amines than physical adsorption. Moreover, the reaction between unprotonated amines and acid (aq.) in water phase likely promoted water absorption. Higher measured partition fraction of dibutylamine was likely due to the reaction with gaseous HCl. The developed method would help provide a deeper understanding of gas-particle partitioning as well as atmospheric evolution of amines.

Influence of meteorological parameters and oxidizing capacity on characteristics of airborne particulate amines in an urban area of the Pearl River Delta, China.

Nine amine species in atmospheric particles during haze and low-pollution days with low and high relative humidity (RH) were analyzed in urban Guangzhou, China. The mean concentrations of total measured amines (Æ©amines) in fine particles were 208 ± 127, 63.7 ± 21.3, and 120 ± 20.1 ng m-3 during haze, low pollution-low RH (LP-LRH), and low pollution-high RH (LP-HRH) episodes, respectively. The dominant amine species were methylamine (MA), dimethylamine (DMA), diethylamine (DEA) and dibutylamine (DBA), which in total accounted for 82-91% of the Æ©amines during different pollution episodes. The contributions of Æ©amines-C to water-soluble organic carbon (WSOC) and Æ©amines-N to water-soluble organic nitrogen (WSON) were 1.52% and 2.49% during haze, 1.24% and 1.96% during LP-LRH, and 2.00 and 2.98% during LP-HRH days, respectively. The mass proportion of Æ©amines in fine particles was higher during LP-HRH periods (0.19%) than during haze and LP-LRH periods (0.16%). The mass proportion of DBA in Æ©amines increased from 7% during haze and LP-LRH episodes to 25% during LP-HRH episodes. Compared with other amines, DBA showed a stronger linear relationship with RH (r = 0.867, p < 0.01), which demonstrates its high sensitivity to high RH conditions. Meteorological parameters (including RH, the mixed layer depth, wind speed and temperature), the oxidizing capacity (ozone concentration), and gaseous pollutants (NOx and SO2) correlated with amines under different pollution conditions. Under high RH, acid-base reactions were the dominant pathway for the gas-to-particle distribution of amines in urban areas, while direct dissolution dominated in the background site. To our knowledge, this study is the first attempt to conduct in situ measurements of particulate amines during different pollution conditions in China, and further research is needed to in-depth understanding of the influence of amines on haze formation.

Volatile organic compounds in an e-waste dismantling region: From spatial-seasonal variation to human health impact.

The dismantling of electrical and electronic waste (e-waste) can release various Volatile organic compounds (VOCs), impacting the surrounding ambient environment. We investigated the spatio-temporal characteristics and health risks of the ambient VOCs emitted in a typical e-waste dismantling region by conducting multi-site sampling campaigns in four seasons. The pollution of benzene, toluene, ethylbenzene, and xylenes (BTEX) in the e-waste dismantling park has relation to e-waste dismantling by seasonal trend analysis. The highest concentrations of most VOCs occurred in winter and autumn, while the lowest levels were observed in summer and spring. The spatial distribution map revealed the e-waste dismantling park to be a hotspot of BTEX, 1,2-dichloropropane (1,2-DCP), and 1,2-dichloroethane (1,2-DCA), while two major residential areas were also the hotspots of BTEX. The e-waste emission source contributed 20.14% to the total VOCs in the e-waste dismantling park, while it was absent in the major residential and rural areas. The cancer risk assessment showed that six VOCs exceeded 1.0 × 10-6 in the e-waste dismantling park, while only three or four compounds exceeded this risk in other areas. The noncancer risks of all compounds were below the safety threshold. This study supplements the existing knowledge on VOC pollution from e-waste dismantling and expands the research scope of chemical pollution caused by e-waste.

Filter-based absorption enhancement measurement for internally mixed black carbon particles over southern China.

The effect of the mixing state of black carbon (BC) on light absorption is of enduring interest due to its close connection to regional/global climate. Herein, we present concurrent measurements of both BC absorption enhancement (Eabs) and the chemical mixing state in southern China. Eabs was obtained by simultaneous measuring the light absorption coefficient using an aethalometer before and after being heated. The observed Eabs was categorized into non- (Eabs ≤ 1.0), slight (1.0 < Eabs ≤ 1.2), and higher (Eabs > 1.2) enhancement groups, and it was compared to the mixing state of elemental carbon (EC) particles detected by a single particle aerosol mass spectrometer (SPAMS). The individual EC-containing particles were classified into four types, including EC with sodium and potassium ion peaks (NaK-EC), long EC cluster ions (Cn+/-, n ≥ 6) with sulfate (EC-Sul1), short EC cluster ions (Cn+/-, n < 6) with sulfate (EC-Sul2), and EC with OC and sulfate (ECOC-Sul). NaK-EC and EC-Sul2 are the dominant EC types. Slight enhancement group is mainly explained by the photochemical production of ammonium sulfate and organics on EC-Sul2 during afternoon hours. In contrast, the higher Eabs is primarily attributed to the enhanced mixing of ammonium chloride with NaK-EC during morning hours, without photochemistry. The characterization of source emissions indicates that NaK-EC is likely from coal combustion and is associated with a relatively higher amount of ammonium chloride. To our knowledge, this is the first report to state that EC particles associated with ammonium chloride have a relatively higher Eabs.

Mechanism of the atmospheric chemical transformation of acetylacetone and its implications in night-time second organic aerosol formation.

Recently, a high concentration of acetylacetone (AcAc) has been measured in China, and its day-time chemistry with OH reaction has been evaluated. The phenomenon has profound implications in air pollution, human health and climate change. To systematically understand the atmospheric chemistry of AcAc and its role in the atmosphere, the night-time chemistry of AcAc with O3 and NO3 radical were investigated in this work in detail using density functional theory. The results show that for O3- and NO3-initiated atmospheric oxidation reactions of AcAc, the barrier energies of O3/NO3-addition are found to be much lower than those of H-abstraction, suggesting that O3/NO3-addition to AcAc is a major contributing pathway in the atmospheric chemical transformation reactions. The total degradation rate constants were calculated to be 2.36 × 10-17 and 1.92 × 10-17 cm3 molecule-1 s-1 for the O3- and NO3-initiated oxidation of AcAc at 298 K, respectively. The half-life of AcAc+O3 in some polluted areas (such as, Pearl River Delta and Yangtze River Delta) is close to 3 h under typical tropospheric conditions. Due to its short half-life, the ozonolysis of AcAc plays a more significant role in the night-time hours, leading to fast transformations to form primary ozonides (POZs). A prompt, thermal decomposition of POZs occurred to yield methylglyoxal, acetic acid and Criegee intermediates, which mainly contributed to the formation of secondary organic aerosol (SOA). Subsequently, using the high-resolution time-of-flight chemical ionization mass spectrometer (HR-ToF-CIMS), a non-negligible concentration of AcAc was measured in the field observation during the night-time in Nanjing, China. The obtained results reveal that the atmospheric oxidation of AcAc can successively contribute to the formation of SOA under polluted environments regardless of the time (day-time or night-time). This is due to its high reactivity to tropospheric oxidant species (such as, O3 and NO3 radicals at night-time).

Spatial and temporal distribution characteristics and ozone formation potentials of volatile organic compounds from three typical functional areas in China.

BACKGROUND: Ozone is currently one of the most important air pollutants. Volatile organic compounds (VOCs) can easily react with atmospheric radicals to form ozone. In-field measurement of VOCs may help in estimating the local VOC photochemical pollution level. METHOD: This study examined the spatial and temporal distribution characteristics of VOCs during winter at three typical sites of varying classification in China; industrial (Guangzhou Economic and Technological Development District (GETDD)), urban (Guangzhou higher education mega center (HEMC)), and rural (Pingyuan county (PYC)), using Proton-Transfer-Reaction Time-of-Flight Mass Spectrometry (PTR-ToF-MS). RESULTS: The concentrations of total VOCs (TVOCs) at the GETDD, HEMC and PYC sites were 352.5, 129.2 and 75.1 ppb, respectively. The dominant category of VOCs is nitrogen-containing VOCs (NVOCs, accounting for 43.3% of TVOCs) at GETDD, of which C4H11N (m/z+ = 74.10, butyl amine) was the predominant chemical species (80.5%). In contrast, oxygenated VOCs (OVOCs) were the most abundant at HEMC and PYC, accounting for 60.2% and 64.1% of the total VOCs, respectively; here, CH4O (m/z+ = 33.026, methanol) was the major compound, accounting for 40.5% of the VOCs at HEMC and 50.9% at PYC. The ratios of toluene to benzene (T/B) were calculated for different measured sites, as the ratios of T/B can reveal source resolution of aromatic VOCs. The average contributions to total ozone formation potentials (OFP) of the total measured VOCs in each area were 604.9, 315.9 and 111.7 µg/m3 at GETDD, HEMC and PYC, respectively; the highest OFP contributors of the identified VOCs were aliphatic hydrocarbons (AlHs) at GETDD, aromatic hydrocarbons (AHs) at HEMC, and OVOCs at PYC. CONCLUSIONS: OFP assessment indicated that the photochemical pollution caused by VOCs at GETDD was serious, and was also significant in the HEMC region. The dominant VOC OFP groups (AlHs and AHs) should be prioritized for control, in order to help reduce these effects.

Does atmospheric processing produce toxic Pb-containing compounds? A case study in suburban Beijing by single particle mass spectrometry.

A single particle aerosol mass spectrometry (SPAMS) was deployed to investigate the mixing state and chemical processing of Pb-rich particles in suburban Beijing. Based on a large dataset of mass spectra, Pb-rich particles were classified into Pb-O-Cl-N-S (55%), Pb-N (17%), Pb-N-S (15%), and Pb-EC (7%). Residual coal combustion, industrial activities, and meteorological conditions were identified as main factors regulating the variations of Pb-rich particles in the atmosphere. The highest abundance of the Pb-rich particles was observed during heating period (HP) primarily due to the increase in coal usage. Pb in Pb-O-Cl-N-S type was identified in forms of PbO, PbCl2, and Pb(NO3)2. Dominantly presented in the form of Pb(NO3)2, Pb-N type represented the completely transformed Pb-rich particles from PbO/PbCl2 by atmospheric processes. It is found that PbCl2 and PbO could be transformed to Pb(NO3)2, highly dependent on the amount of NO2 and RH. Significant enhancement of nitrate in Pb-O-Cl-N-S particles was observed when the RH was greater than 60%, emphasizing the importance of heterogeneous hydrolysis of N2O5 on the formation of Pb(NO3)2. Compared with non-carcinogenic PbCl2/PbO and insoluble PbO, soluble and carcinogenic Pb(NO3)2 produced by atmospheric processes may significantly enhance negative effects of Pb-rich particles on human health and the ecosystem.

Polybrominated diphenyl ethers in the environment and human external and internal exposure in China: A review.

Polybrominated diphenyl ethers (PBDEs) are widely used as brominated flame retardants. Because of their toxicity and persistence, some PBDEs were restricted under the Stockholm Convention in 2009. Since then, many studies have been carried out on PBDEs in China and in many other countries. In the present review, the occurrences and contamination of PBDEs in air, water, sediment, soil, biota and daily food, human blood, hair, and other human tissues in China are comprehensively reviewed and described. The human exposure pathways and associated health risks of PBDEs are summarized. The data showed no obvious differences between North and South China, but concentrations from West China were generally lower than in East China, which can be mainly attributed to the production and widespread use of PBDEs in eastern regions. High levels of PBDEs were generally observed in the PBDE production facilities (e.g., Jiangsu Province and Shandong Province, East China) and e-waste recycling sites (Taizhou City, Zhejiang Province, East China, and Guiyu City and Qingyuan City, both located in Guangdong Province, South China) and large cities, whereas low levels were detected in rural and less-developed areas, especially in remote regions such as the Tibetan Plateau. Deca-BDE is generally the major congener. Existing problems for PBDE investigations in China are revealed, and further studies are also discussed and anticipated. In particular, non-invasive matrices such as hair should be more thoroughly studied; more accurate estimations of human exposure and health risks should be performed, such as adding bioaccessibility or bioavailability to human exposure assessments; and the degradation products and metabolites of PBDEs in human bodies should receive more attention. More investigations should be carried out to evaluate the quantitative relationships between internal and external exposure so as to provide a scientific basis for ensuring human health.

Oxalate Formation Enhanced by Fe-Containing Particles and Environmental Implications.

We used a single particle mass spectrometry to online detect chemical compositions of individual particles over four seasons in Guangzhou. Number fractions (Nfs) of all the measured particles that contained oxalate were 1.9%, 5.2%, 25.1%, and 15.5%, whereas the Nfs of Fe-containing particles that were internally mixed with oxalate were 8.7%, 23.1%, 45.2%, and 31.2% from spring to winter, respectively. The results provided the first direct field measurements for the enhanced formation of oxalate associated with Fe-containing particles. Other oxidized organic compounds including formate, acetate, methylglyoxal, glyoxylate, purivate, malonate, and succinate were also detected in the Fe-containing particles. It is likely that reactive oxidant species (ROS) via Fenton reactions enhanced the formation of these organic compounds and their oxidation product oxalate. Gas-particle partitioning of oxalic acid followed by coordination with Fe might also partly contribute to the enhanced oxalate. Aerosol water content likely played an important role in the enhanced oxalate formation when the relative humidity is >60%. Interactions with Fe drove the diurnal variation of oxalate in the Fe-containing particles. The study could provide a reference for model simulation to improve understanding on the formation and fate of oxalate, and the evolution and climate impacts of particulate Fe.

Studies on effects of static electric field exposure on liver in mice.

With the development of ultra-high-voltage direct-current transmission, the intensity of static electric field (SEF) under transmission lines increased, which has aroused public attention on its potential health effects. In order to examine effects of SEF exposure on liver, institute of cancer research mice were exposed to SEF with intensities of 27.5 kV/m, 34.7 kV/m and 56.3 kV/m, respectively. In each intensity of SEF exposure, a corresponding sham exposure group was used. Several indices relating to liver function (aspartate aminotransferase (AST) and alanine aminotransferase (ALT)) and oxidative stress (superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and malondialdehyde (MDA)) were tested after exposure of 7, 14, 21 and 35 days. Results showed that exposure to SEF with intensities of 27.5 kV/m and 34.7 kV/m for 35 days did not significantly influence any detected indices above. Under SEF exposure with intensity of 56.3 kV/m, the SOD activity in liver was significantly increased after exposure of 7 and 14 days. However, no significant increase was found in MDA content as well as the activities of AST and ALT between exposure group and sham exposure group during SEF exposure of 56.3 kV/m. It suggested that from three SEF intensities, only exposure to SEF with intensity of 56.3 kV/m (7 and 14 days) caused a temporary oxidative stress response in liver expressed by the increase in activity of SOD, but it did not produce oxidative damage. This biological effect may be related to the increase of mitochondrial membrane potential of hepatocytes caused by SEF exposure. When the membrane potential exceeds a threshold, Q cycle in mitochondria will be affected, which will result in an increase of superoxide anion concentration and ultimately an oxidative stress.

A comparative study on effects of static electric field and power frequency electric field on hematology in mice.

With the development of the ultra high voltage transmission technology, the voltage level of transmission line rised. Accordingly, the strength of electric field in the vicinity of transmission line increased, thus possible health effects from electric field have caused many public attentions. In this study, in order to compare effects induced by static electric field (SEF) and power frequency electric field (PFEF) on immune function, Institute of Cancer Research (ICR) mice were exposed to 35 kV/m SEF (0 Hz) and PFEF (50 Hz),respectively. Several indicators of white blood cell, red blood cell as well as hemoglobin in peripheral blood were tested after exposure of 7, 14 and 21 days, respectively. There was no significant difference in any indicators under SEF exposure of 35 kV/m for 7d, 14d and 21d between experimental group and control group. Under the PFEF exposure of 35 kV/m, white blood cell count significantly reduced after exposure of 7d, 14d and 21d. Meanwhile, red blood cell count significantly reduced after exposure of 7d, and returned to normal level through the compensatory response of organism after exposure of 14d and 21d. Hemoglobin concentration significantly decreased only after exposure of 21d. Based on tested results of hematological indicators, SEF exposure of 35 kV/m did not affect immune functions in mice but PFEF exposure of 35 kV/m could cause a decline of immune function. This difference of effects from SEF and PFEF on immune function was possibly caused by the difference of the degree of molecular polarization and ion migration in organism under exposure of two kinds of electric fields.