Bioaerosol characterization by flow cytometry with fluorochrome

Traditional culture and microscopy methods for evaluation of bioaerosols are slow, tedious, and rather imprecise. In this study, the application of flow cytometry that was combined with a fluorescent technique (FCM/FL) was evaluated as a technique to quickly and accurately determine and quantify the total concentration and viability of bioaerosols. The optimal conditions of five fluorescent dyes [acridine orange (AO), SYTO-13, propidium iodide (PI), YOPRO-1, and 5-cyano-2,3-ditolytetrazolium chloride (CTC)] used in FCM/FL were determined for laboratory samples of bacterial aerosols (Escherichia coli, and endospores of Bacillus subtilis) and fungal aerosols (Candida famata and Penicillium citrinum spores). Based on the measured cell concentration, fluorescence intensity, and staining efficiency as indicators for dye performance evaluation, SYTO-13 was found to be the most suitable fluorescent dye for determining the total concentration of the bioaerosols, as well as YOPRO-1 was the most suitable for determining viability. Moreover, the established optimal FCM/FL with dyes was validated for characterizing microorganism profiles from both air and water samples from the aeration tank of hospital wastewater treatment plant. In conclusion, the FCM/FL successfully assessed the total concentration and viability for bacterial and fungal microorganisms in environmental field samples.     

Recovery of Francisella tularensis from soil samples by filtration and detection by real-time PCR and cELISA

The aim of this study was to develop a specific and highly sensitive method able to detect very low concentrations of Francisella tularensis in soil samples by real-time PCR (qPCR) with SYBR Green I. tul4 gene, which encodes the 17-kDa protein (TUL4) in F. tularensis strains, was amplified using a LightCycler (LC) device. We achieved a detection limit of 0.69 fg of genomic DNA from F. tularensis subp. holarctica live vaccine strain (LVS), corresponding to a value less than 3.4 genome equivalents per reaction. The qPCR was shown to be specific, highly sensitive and reproducible. In addition, we evaluated 2 new methods for recovering bacteria from soil based on 1-step filtration using glass fiber filters and PVDF filters. These filtration methods enabled us to recover F. tularensis efficiently from soil samples. As few as 50 CFU per 0.5 g of soil were detected by qPCR. Capture enzyme-linked immunosorbent assay (cELISA) allowed us to detect and quantify the amount of bacteria recovered from soil by an immunological method. Although qPCR was more sensitive than cELISA, we did not observe substantial differences in the amount of bacteria quantified by both methods.     

Detection and quantification of major toxigenic Microcystis genotypes in Moo-Tan reservoir and associated water treatment plant

Two molecular methods, denaturing gradient gel electrophoresis (DGGE) and quantitative real-time polymerase chain reaction (qPCR) with the Universal ProbeLibrary (UPL) probe, were developed and used for the characterization and quantification of several microcystin producers in Moo-Tan Reservoir (MTR), Taiwan and its associated water treatment plant (Shih-Men Water Treatment Plant, SMWTP). Internal transcribed spacer (ITS) sequence, a highly diversified region between the 16S rRNA and 23S rRNA genes, was used to further identify the isolated strains from MTR and also used in DGGE for the detection of the specific DNA fragments and biomarkers for 11 strains observed in MTR. These ITS-DGGE biomarkers were successfully applied to monitor the community changes of potential toxigenic Microcystis sp. over a period of five years. Two highly specific primers were combined with UPL probes to measure microcystins synthesis gene (mcyB) and phycocyanin intergenic spacer region (cpcB) concentrations in water samples. The copy concentrations of UPL-mcyB and UPL-cpcB correlated well with MC-RR concentrations/water temperature and Microcystis sp. cell numbers in the water samples, respectively. For SMWTP, toxin concentrations were low, but the DGGE bands clearly demonstrated the presence of potential microcystin producers in both water treatment plants and finished water samples. It was demonstrated that toxigenic Microcystis sp. may penetrate through the treatment processes and pose a potential risk to human health in the drinking water systems.     

A perspective on the prevalence of DNA enteric virus genomes in anaerobic-digested biological wastes

The major goal of this study is to gain a perspective on the prevalence of DNA enteric virus genomes in mesophilic anaerobic-digested (MAD) sewage sludge and manure by comparing their quantitative PCR (qPCR) concentrations and removals with traditional fecal indicators (Escherichia coli, enterococci, and Bacteroidetes). In addition, relationships between qPCR and culture measurements of fecal indicators (FIs) were determined. There was no significant difference between the qPCR concentrations of human adenovirus and E. coli/enterococci in MAD sewage sludge; however, the qPCR concentrations of bovine adenovirus were significantly lower than FIs and bovine polyomavirus (BPyV) in MAD manure. The qPCR concentrations of human polyomavirus were slightly lower than E. coli and enterococci (p ≤ 0.05), but no significant difference was observed between the qPCR concentrations of BPyV and FIs. The digestion treatment achieved higher genome removal of bovine DNA enteric viruses than FIs (p ≤ 0.05). Significant correlations were observed between qPCR and culture measurements of FIs, but the concentrations and removals of FIs determined by qPCR assays were still significantly different than those determined by culture assays. Overall, we determined that the prevalence of DNA enteric virus genomes in MAD biological wastes was high due to their comparable in qPCR concentrations to FIs, indicating that mesophilic anaerobic digestion treatment alone may not be effective enough to remove DNA viral pathogens in biological wastes.     

Quantitative PCR analysis of fungi and bacteria in building materials and comparison to culture-based analysis

Prolonged moisture on building materials can lead to microbial growth on them. Microbes can emit spores, metabolites and structural parts into the indoor air and thus, cause adverse health effects of people living and working in these buildings. So far, culture methods have been used for assessment of microbial contamination of building materials. In this work, we used quantitative PCR (qPCR) for the detection of selected fungal and bacterial groups in 184 building materials of different types and compared the results with culture-based analysis. Nine either commonly found species, genera or groups of fungi, or those considered as moisture damage indicators, and one bacterial genus, Streptomyces, were determined using qPCR. Fungi and mesophilic actinomycetes were also cultivated using standard media and conditions of the routine analysis. The bacterial genus Streptomyces and the fungal group Penicillium/Aspergillus/Paecilomyces were the most prevalent microbial groups in all building material types, followed by Stachybotrys chartarum and Trichoderma viride/atroviride/koningii. The highest prevalences, concentrations and species diversity was observed on wooden materials. In general, the results of the two methods did not correlate well, since concentrations of fungi and streptomycetes were higher and their occurrence more prevalent when determined by qPCR compared to culture-based results. However, with increasing concentrations, the correlation generally increased. The qPCR assay did not detect Aspergillus versicolor and Acremonium strictum as often as culture.     

Measurement of the proximity effect for indoor air pollutant sources in two homes

Personal exposure to air pollutants can be substantially higher in close proximity to an active source due to non-instantaneous mixing of emissions. The research presented in this paper quantifies this proximity effect for a non-buoyant source in 2 naturally ventilated homes in Northern California (CA), assessing its spatial and temporal variation and the influence of factors such as ventilation rate on its magnitude. To quantify how proximity to residential sources of indoor air pollutants affects human exposure, we performed 16 separate monitoring experiments in the living rooms of two detached single-family homes. CO (as a tracer gas) was released from a point source in the center of the room at a controlled emission rate for 5-12 h per experiment, while an array of 30-37 real-time monitors simultaneously measured CO concentrations with 15 s time resolution at radial distances ranging from 0.25-5 m under a range of ventilation conditions. Concentrations measured in close proximity (within 1 m) to the source were highly variable, with 5 min averages that typically varied by >100-fold. This variability was due to short-duration (<1 min) pollutant concentration peaks ("microplumes") that were frequently recorded in close proximity to the source. We decomposed the random microplume component from the total concentrations by subtracting predicted concentrations that assumed uniform, instantaneous mixing within the room and found that these microplumes can be modeled using a 3-parameter lognormal distribution. Average concentrations measured within 0.25 m of the source were 6-20 times as high as the predicted well-mixed concentrations.     

Integration of high volume portable aerosol-to-hydrosol sampling and qPCR in monitoring bioaerosols

In this study, the integration of a high volume, portable aerosol-to-hydrosol sampling technique and quantitative polymerase chain reaction (qPCR) was investigated for bioaerosol monitoring by adapting the RCS High Flow to sample air with mineral-oil-strips. Bacillus subtilis var niger and Pseudomonas fluorescens were aerosolized and collected by the RCS High Flow loaded with mineral-oil-strips for 1, 2 and 5 min. In addition, the adapted aerosol-to-hydrosol sampler was also tested for sampling environmental bacterial aerosols in four different environments (a back yard, a student dorm, a dining hall, and a play ground). The performances of the RCS High Flow with mineral-oil-strips were compared with the use of agar strips under similar conditions in all experiments. Air samples collected by the RCS High Flow were cultured, and in addition those collected with mineral-oil-strips were also quantified using qPCR. When sampling B. subtilis var niger aerosols, the use of mineral-oil-strips was shown to report significantly higher culturable concentrations than those obtained by agar strips regardless of the sampling time tested (p-value = 0.04). In contrast, the differences between the two methods when sampling P. fluorescens aerosols were not statistically significant (p-value = 0.5). When coupled with qPCR, the RCS High Flow loaded with mineral-oil-strips obtained significantly higher bacterial aerosol concentrations than those detected by the culturing method. The sampling time was observed to have negligible effects on the efficiency of the technology developed here. When sampling in different environments, the use of mineral-oil-strip was observed to yield significantly higher, about 4-12 times, culturable bacterial aerosol concentration levels compared to the use of agar. This study demonstrated a high volume (100 L min?1) portable aerosol-to-hydrosol sampling technique, holding broad promise in monitoring airborne biological threats when coupled with qPCR technology. Yet, caution should be taken in relating the bioaerosol concentrations to health risks as qPCR detects both culturable and non-culturable cells including inactivated ones.     

Background concentrations of individual and total volatile organic compounds in residential indoor air of Schleswig-Holstein, Germany

During a monitoring campaign concentrations of volatile organic compounds (VOCs) were measured in indoor air of 79 dwellings where occupants had not complained about health problems or unpleasant odour. Parameters monitored were the individual concentration of 68 VOCs and the total concentration of all VOCs inside the room. VOCs adsorbed by Tenax TA were then analysed by means of thermal desorption, gas chromatography and mass spectrometry. The analytical procedure and quantification was done according to the recommendation of the ECA-IAQ Working Group 13 which gave a definition of the total volatile organic compound (TVOC) concentration. Using this recommendation TVOC-concentrations ranged between 33 and 1600 microg m(-3) with a median of 289 microg m(-3). Compounds found in every sample and with the highest concentrations were 2-propanol, alpha-pinene and toluene. Save for a few samples, all concentrations measured have been a factor 2 to 10 lower, compared to data from similar studies. Only a few terpenes and aldehydes were found exceeding published reference data or odour threshold concentrations. However, it has been found that sampling and analysing methods do have a considerable impact on the results, making direct comparisons of studies somewhat questionable. 47% of all samples revealed concentrations exceeding the threshold value of 300 microg TVOC m(-3) set by the German Federal Environmental Agency as a target for indoor air quality. Using the TVOC concentration as defined in the ECA-IAQ methodology is instrumental in assessing exposure to VOCs and identifying sources of VOCs. The background concentrations determined in this study can be used to discuss and interpret target values for individual and total volatile organic compounds in indoor air.     

Assessment of the Water Quality of Troia for the Multipurpose Usages

The aim of this study was to determine the origin and quality of waters in Troia. For this purpose total of 25 water samples including 2 springs, 14 surfaces and 9 groundwaters, were collected at eight different times. Global positioning system (GPS) was used to determine to coordinates of sampling points. The concentration of 6 minor elements (B, Cu, F, Fe, Pb and Zn), 9 major anions and cations (Na(+), Ca(2+), K(+), Mg(2+), SO(4)(2-), PO(4)(3-), HCO(3)(-), Cl(-) and, CO(3)(2-)) were determined by spectrometric, colorimetric and volumetric methods. Water pH, EC, DO, ORP and TDS were measured in situ using probes. The data showed that the concentrations of most of minor elements were below the EPA and TSE limits except Pb which ranged between 0.001 and 4.832 mg L(-1). Statistically significant relationships (P<0.01 and r>0.70) were observed between Fe and Cu, Cu and K(+), Cu and Ca(2+), B and Na(+), Na(+) and K(+). Assessing the water based on irrigation using Wilcox model showed that some well waters were not suitable for irrigation. Troia water was found to be highly corrosive and the average corrosion coefficients varied from 0.5 to 4.6. According to the Piper and Schoeller diagrams results, the water in Troia was classified as mixed water type.     

Nonpoint Source Pollution Assessment of Wujiang RiverWatershed in Guizhou Province,SW China

The amount of pollution from nonpoint sources flowing in the streams of the Wujiang River watershed in Guizhou Province, SW China, is estimated by a geographic information system (GIS)-based method using rainfall, surface runoff and land use data. A grid of cells of 100 m in size is laid over the landscape. For each cell, mean annual surface runoff is estimated from rainfall and percent land use, and expected pollutant concentration is estimated from land use. The product of surface runoff and concentration gives expected pollutant loading from that cell. These loadings are accumulated going downstream to give the expected annual pollutant loadings in streams and rivers. By dividing these accumulated loadings by the similarly accumulated mean annual surface runoff, the expected pollutant concentration from nonpoint sources is determined for each location in a stream or river. Observed pollutant concentrations in the watershed are averaged at each sample point and compared to the expected concentrations at the same locations determined from the grid cell model. In general, annual nonpoint source nutrient loadings in the Wujiang River watershed are seen to be predominantly from the agricultural and meadow areas. The total annual loadings through the outlet of the watershed are 40,309 and 2,607 tons for total nitrogen (TN) and total phosphorus (TP), respectively.     

前处理方法对水体总磷测定值的影响研究

研究了水样静置30 min和全部混合立即测定2种前处理方法对江苏省环太湖15条主要出入湖河流总磷测定值的影响,结果表明,采样后静置30 min测定的总磷浓度较低,仅为全部混匀立即测定总磷浓度的46%～80%;水体中漂浮水华蓝藻数量是影响2种前处理方法总磷测定结果差异性的重要因素,去除漂浮水华蓝藻较多的7条入湖河流监测数据后,静置30 min测定的总磷浓度为全部混匀立即测定总磷浓度的71%～80%。提出,基于不同的测定目的,应有针对性地选择总磷前处理方法,在水环境质量状况评估时,可参照国家标准或最新技术规定的前处理方法执行,以保证总磷浓度的可比性;在进行总磷入湖通量研究时,建议采用全部混合立即测定的前处理方法,以反映水体中实际总磷浓度;在不同国家水体总磷浓度比较时,建议采用相同的前处理方法进行总磷浓度测定。     

The Emissions of Major Aromatic Voc as Landfill Gas from Urban Landfill Sites in Korea

In this study, concentrations of major aromatic VOCs were determined from landfill gas (LFG) at a total of five municipal landfill sites in Korea including Nan Ji (NJ), Woon Jung (WJ), Sam Poong (SP), Hoei Chun (HC), and No Hyung (NH). The concentration levels of those VOC were found to be significantly different, mainly as a function of such a parameter as landfill aging. The VOC concentrations measured from the unclosed landfill sites (e.g., WJ) were characterized by exceedingly high values above a few tens of ppm. However, the results of the abandoned site (e.g., SP) were about three orders of magnitude lower than the others so as to merely exceed the typical ambient concentration levels. It was most striking to find a systematic dominance of toluene over other aromatic VOC under most circumstances. The LFG flux values of all aromatic VOC and the four specific major ones (termed as BTEX: benzene, toluene, ethylbenzene, and xylene) were also computed for each vent pipe from all study sites using their concentrations and the concurrently determined environmental parameters. The results, if calculated in terms of the average BTEX quantity emitted per vent pipe, showed that the magnitude of their emissions can vary substantially, with the values ranging from 0.05 (SP) to 49.2 kg yr⁻¹ (WJ in wintertime). The LFG flux values of aromatic VOC, when compared to the contribution of non-methane hydrocarbons (NMHC), were able to explain a constant, but minor, proportion of the LFG carbon budget.     

激光散射法和便携式氢火焰离子化检测器法直读监测油烟排放

餐饮业油烟排放具有排放浓度不稳定、波动较大、排放时间短等特性，存在瞬时排放高值现象，油烟"看得见"和"闻得着"的问题依然存在，因此对油烟实现快速、及时、直读监测尤为必要。基于一种浓度可控且稳定的油烟产生技术，对直读激光散射法与经典手工称重法测定油烟颗粒物浓度值的数据线性关系进行了分析，发现2种方法数值的相关系数达0.99，通过直读修正激光散射法可以有效地测定油烟颗粒物浓度，并测定了不同水汽含量下油烟颗粒物排放情况，发现当相对湿度超过70%时，油烟颗粒物浓度测定值会发生突变。使用便携式氢火焰离子化检测器法（FID）和光离子化检测器法（PID）测定了不同油温下油烟中非甲烷总烃（NMHC）浓度，发现FID对油烟中NMHC的变化反应及时，能够较好地测定油烟中挥发性有机物的排放量。     

Detection and quantification of Cladosporium in aerosols by real-time PCR

Cladosporium is one of the most common airborne molds found in indoor and outdoor environments. Cladosporium spores are important aeroallergens, and prolonged exposure to elevated spore concentrations can provoke chronic allergy and asthma. To accurately quantify the levels of Cladosporium in indoor and outdoor environments, two real-time PCR systems were developed in this study. The two real-time PCR systems are highly specific and sensitive for Cladosporium detection even in a high background of other fungal DNAs. These methods were employed to quantify Cladosporium in aerosols of five different indoor environments. The investigation revealed a high spore concentration of Cladosporium (10(7) m(-3)) in a cow barn that accounted for 28-44% of the airborne fungal propagules. In a countryside house that uses firewood for heating and in a paper and pulp factory, Cladosporium was detected at 10(4) spores m(-3), which accounted for 2-6% of the fungal propagules in the aerosols. The concentrations of Cladosporium in these three indoor environments far exceeded the medical borderline level (3000 spores m(-3)). In a power station and a fruit and vegetable storage, Cladosporium was found to be a minor component in the aerosols, accounted for 0.01-0.1% of the total fungal propagules. These results showed that monitoring Cladosporium in indoor environments is more important than in outdoor environments from the public health point of view. Cladosporium may not be the dominant fungi in some indoor environments, but its concentration could still be exceeding the threshold value for clinical significance. The methods developed in this study could facilitate accurate detection and quantification of Cladosporium for public health related risk assessment.     

Prevalence of multidrug-resistant,coagulase-positive Staphylococcus aureus in nasal carriage,food, wastewater and paper currency in Jalandhar city (north-western), an Indian state of Punjab

Eighteen sites impacted by abandoned mine drainage (AMD) in Pennsylvania were sampled and measured for pH, acidity, alkalinity, metal ions, and sulfate. This study compared the accuracy of four acidity calculation methods with measured hot peroxide acidity and identified the most accurate calculation method for each site as a function of pH and sulfate concentration. Method E1 was the sum of proton and acidity based on total metal concentrations; method E2 added alkalinity; method E3 also accounted for aluminum speciation and temperature effects; and method E4 accounted for sulfate speciation. To evaluate errors between measured and predicted acidity, the Nash-Sutcliffe efficiency (NSE), the coefficient of determination (R ²), and the root mean square error to standard deviation ratio (RSR) methods were applied. The error evaluation results show that E1, E2, E3, and E4 sites were most accurate at 0, 9, 4, and 5 of the sites, respectively. Sites where E2 was most accurate had pH greater than 4.0 and less than 400 mg/L of sulfate. Sites where E3 was most accurate had pH greater than 4.0 and sulfate greater than 400 mg/L with two exceptions. Sites where E4 was most accurate had pH less than 4.0 and more than 400 mg/L sulfate with one exception. The results indicate that acidity in AMD-affected streams can be accurately predicted by using pH, alkalinity, sulfate, Fe(II), Mn(II), and Al(III) concentrations in one or more of the identified equations, and that the appropriate equation for prediction can be selected based on pH and sulfate concentration.     

Exposure to airborne organophosphates originating from hydraulic and turbine oils among aviation technicians and loaders

This study describes the potential for occupational exposure to organophosphates (OPs) originating from turbine and hydraulic oils, among ground personnel within the aviation industry. The OPs tri-n-butyl phosphate (TnBP), dibutyl phenyl phosphate (DBPP), triphenyl phosphate (TPP) and tricresyl phosphate (TCP) have been emphasized due to their use in such oils. Oil aerosol/vapor and total volatile organic compounds (tVOCs) in air were also determined. In total, 228 and 182 OPs and oil aerosol/vapor samples from technician and loader work tasks during work on 42 and 21 aircrafts, respectively, were collected in pairs. In general, the measured exposure levels were below the limit of quantification (LOQ) for 84%/98% (oil aerosol) and 82%/90% (TCP) of the samples collected during technician/loader work tasks. The air concentration ranges for all samples related to technician work were 相似文献   

Distribution and sources of mercury in soils from former industrialized urban areas of Beijing, China

Fifty-seven typical surface soils and 108 deeper soils were collected from five former industrial sites in Beijing and concentrations of total Hg (SigmaHg) as well as pH, total carbon (TC), total nitrogen (TN), total sulfur, and dissolved organic carbon concentrations determined. The mean concentration of SigmaHg in surface soils was significantly greater than background concentrations in the vicinity of Beijing. Forty-eight percent of the samples exceeded the "critical" concentration of 1.0 mg Hg/kg, dry weight in soils, which has been established by the Chinese government. At depths of 0-80 cm in the soil, profile concentrations of SigmaHg also exceeded the background value. There were significant correlations between concentrations of SigmaHg, TC, and TN in the industrial soils. The greater concentration of SigmaHg in most soils could have been due in part to combustion of coal and leakage from industrial processes.     

An examination of the toxic properties of water extracts in the vicinity of an oil sand extraction site

The industrial extraction of oil sands (OS) in northern Alberta, Canada, has raised concerns about the quality of the Athabasca River. The purpose of this study was to examine the toxic properties of various water extracts on Oncorhynchus mykiss trout hepatocytes. The water samples were fractionated on a reverse-phase C(18) cartridge and the levels of light-, medium- and heavy-weight polycyclic aromatic hydrocarbons (PAHs) were determined by fluorescence spectroscopy. Primary cultures of trout hepatocytes were exposed for 48 h at 15 °C to increasing concentrations of the C(18) extract corresponding to 0.02, 0.1, 0.5 and 2.5X concentrations from upstream/downstream sites in the Athabasca River, lake and groundwater samples, OS tailings and interceptor well-water samples. Changes in cell viability, phase I and phase II biotransformation enzymes (cytochrome P4501A and glutathione S-transferase activities), oxidative damage (lipid peroxidation LPO) and genotoxicity (single and double DNA strand breaks) were monitored in post-exposure cells. The water samples decreased cell viability and increased all the above endpoints at thresholds of between 0.02 and 0.1X the water concentration. The most responsive biomarker was DNA damage but it also offered the least discrimination among sites. LPO was higher at sites downstream of the industrial operations compared to upstream sites. A decision tree analysis was performed to formulate a set of rules by which to identify the distinctive properties of each type of water samples. The analysis revealed that OS tailings and interceptor waters were characterized by an increased concentration in light PAHs (>42 μg L(-1)) and this fraction represented more than 85% of the total PAHs. These samples also inhibited GST activity, which could compromise the elimination of genotoxic PAHs present in the system. An analysis of groundwater samples revealed a contamination pattern similar to that for OS tailings. There is a need for more research into specific biomarkers of toxicity from OS tailings compounds such as naphthenic acids, light PAHs among others, which are a characteristic fingerprint of OS extraction activities.     

Passive aerosol sampler for particle concentrations and size distributions

This research evaluated the UNC passive aerosol sampler as a tool to measure particle mass concentrations and size distributions. The exposure scenario represented high concentrations and exposure periods of a few hours. Mass concentrations measured with the passive sampler were compared to concentrations measured using both a dichotomous sampler and an aerodynamic particle sizer (APS). In addition, the size distributions measured with the passive sampler were compared to those measured using the APS. Mass concentrations measured using the dichotomous sampler and the APS agreed well. The passive sampler tracked, but tended to overestimate, mass concentrations measured by the other two instruments. Size distributions measured with the passive sampler followed the general pattern of those measured using the APS. Overall, the passive sampler demonstrated both its utility and its limitations in these tests. The concentration measurements and size distributions found using passive samplers were more variable than those of the other instruments, but generally followed the data taken using the other methods. The advantages of low cost and ease of use offset the limitations in data quality with the passive sampler; these advantages are particularly welcome for sampling situations where aerosol properties vary over space or time.     

Characterization of ambient air quality during a rice straw burning episode

Spatiotemporal characteristics and impact of ambient air-quality attributed to open burning of rice straw were analyzed and estimated with measured data. Two multivariate analytic methods, factor analysis and cluster analysis, were adopted to analyze the temporal and spatial impact on ambient air-quality during the rice straw burning episode. Temporal features of three scenarios were cited to compare the concentrations for ambient air-quality between the rice straw burning episode and non-episodes over two typical stations by factor analysis. Factor analysis demonstrated that the first rotational component, identified as being highly correlated to the open burning of rice straw, accounts for about 40% of the concentration variance for ambient air-quality. In typical air-quality stations, the average hourly incremental concentrations between the episode and non-episodes were greater than 300 μg m(-3) for PM(10), 1.0 ppm for CO and 35 ppb for NO(2) during the impact of rice straw burning. Factor analysis presented that the first rotated component was highly correlated with several primary pollutants (NO(2), NMHC, PM(10) and CO) during the rice straw burning episode, while every component was only highly correlated with a unique air pollutant during non-episodes. The delineation isopleths indicated that factor analysis could serve as a better method than cluster analysis and provides cross-county cooperation for local governments located in the same separated district during the rice straw burning season. The results of factor analysis revealed that CO is the best index to demonstrate the impact of rice straw burning than the other six air pollutants measured during the episode. Backward trajectory analysis supplied a cause-effect relationship between measured stations and specific rice planted regions during the rice straw burning episode.