Air Particulate Samples Research Articles

Vertex vectors sequential projection for self-modeling curve resolution of two-way data

A method for self-modeling curve resolution (SMCR) of two-way data is proposed. It is demonstrated that with an arbitrary p-normalization ( p > 1), the two-way data points are located on a certain polyhedral hyper-“spherical” surface with the vertices constituted by the pure variables. This elucidates the geometry of an old discovery that two-way data points are bracketed by the pure variables. Thus a property of the polyhedral hyper-“sphere” is given, which states that the vertex vectors maximize a certain quadratic form over all points on the hyper-“spherical” surface. A procedure for determining pure variables in two-way data is then developed. Finally, an optimization algorithm to refine the resolution is suggested. With a good starting estimate that is as close as possible to the true pure profiles, the proposed method is expected to yield improved resolution compared to traditional resolution techniques. The proposed method is evaluated with two simulated data sets and two real chemical data sets from hyphenated chromatography–diode array detection (HPLC–DAD) of polyaromatic hydrocarbon in air particle samples. The results show that the proposed method gives satisfactory resolution for the four data sets.

Sedimentation field-flow fractionation-inductively coupled plasma optical emission spectrometry: size-based elemental speciation of air particulates

The applicability of sedimentation field-flow fractionation-inductively coupled plasma optical emission spectrometry (SdFFF-ICP-OES) was investigated for the elemental size characterization of air particulate matters less than 10 μm (PM10). The effects of various dispersing agents and pH values on the dispersion stability of air particulates were examined by zeta potential measurement. Anionic surfactants, which were 0.1% FL-70® (a powerful alkaline detergent) and 0.1% sodium dodecyl sulfate (SDS), exhibited zeta potential values more negative than −30 mV, suggesting that both surfactants could efficiently disperse air particulates. A 0.1% FL-70 with pH 8 was chosen as both dispersing agent and carrier liquid. The developed SdFFF method provided satisfactory separation efficiency and reproducibility (<3% RSD). Broad size distributions were obtained for air particulate samples collected from five locations. Nonetheless, peak maxima and the distribution ranges of air particulates collected from one location were different from the others. Further, a hyphenated technique of SdFFF and ICP-OES was employed to study size-based elemental distribution of air particles. An ultrasonic nebulizer was used in order to increase sample transport efficiency and hence improve the sensitivity of ICP-OES detection. Aluminium, Fe, and Ti were detected across the whole size range of air particulate sample.

Format IIA Model Infection Control Program for Commissioning an Ambulatory Surgery Center

ISSUE: Construction-related infection control guidelines for healthcare facilities are primarily directed toward preventing healthcare-associated fungal infection (e.g., Aspergillus species) in occupied buildings. There are, however, no generally accepted standards for infection control commissioning of a newly constructed ambulatory surgery center. A model infection control program for commissioning such a building is presented. PROJECT: To develop an infection control-commissioning program for a newly constructed ambulatory surgery center; to confirm HVAC system cleanliness, operation, and filtration efficiency; building cleanliness; and to establish acceptance criteria for airborne particulate and opportunistic fungal species. RESULTS: A multidisciplinary team was created including representatives from Infection Control, Infectious Diseases, Construction Management, Administration, Laboratory Medicine, Environmental Services, Industrial Hygiene consultants and contractors. A program of sequential, step-wise inspections and testing was developed. The program elements included surface sampling of the HVAC system and duct interiors; HVAC and room pressure relationship testing, and filter efficiency testing; moisture testing; and fungal and particulate air sampling. LESSONS LEARNED: The use of multiple inspection and testing methods (visual inspection, pressure testing, particle counters, and air samples) provided the most useful information for infection control commissioning. Close partnering with the construction contractor was the single most significant contributor to the success of the infection control commissioning process.

Promoter and Mutagenic Activity of Particulate Matter Collected from Urban Air

Urban air particulate samples were collected on a quartz fiber filter with a High Volume Air Sampler, which was placed on the roof of the National Institute of Public Health, Minato-ku, Tokyo. Those samples were tested in both transformation assay using Bhas42 cells (Bhas assay) as a bioassay for cancer promoters and in the Ames microsuspension method as for initiators. Good dose-response relations were observed with both testing methods, and the samples showed mutagenicity and promoter activity. A comparison per particle weight between the samples collected in spring and autumn indicated that the value was higher in autumn samples, suggesting that mutagenic substances and cancer promoters might be polluting the air and be correlated with each other. Therefore, to monitor the carcinogenic-related activity of air pollutants, not only the mutagenicity assay but also bioassays for cancer promoters are required.

Analysis of polycyclic aromatic hydrocarbons in airborne particles using open-vessel focused microwave-assisted extraction

A procedure to extract polycyclic aromatic hydrocarbons (PAHs) from airborne particles using open-vessel focused microwave-assisted extraction (FMAE) is proposed. Parameters which might affect extraction efficiency such as solvent composition, extraction time, microwave power, and sample water addition were investigated. Recoveries for PAHs from urban dust standard reference material (SRM) 1649a were between 77 and 116% with relative standard deviations between 2 and 18% on the basis of certified values by using an optimized condition: in a 20 ml 5% acetone in toluene at 150 W of microwave power for 20 min extraction. The optimized FMAE condition was compared to Soxhlet method on the extraction of standard reference material and real particulate air samples collected from urban area.

Long‐term decrease of cadmium concentrations in the Canadian Arctic air

Average cadmium concentrations in the air (particulate samples) at two Canadian Arctic sites, Resolute (74.7°N, 95.0°W) and Coral Harbor (64.2°N, 83.3°W) declined from about 0.2 ng m−3 to about 0.05 ng m−3 between the early 1970s and 2000. Cadmium concentrations in the air at southern Canada sites were much higher (0.05–1.12 ng m−3) than those measured in the Arctic. The concentrations of cadmium measured at all sites decreased by a factor of three to seven between 1973 and 2000. This decrease correlates with the reduction in anthropogenic emissions from the production of non‐ferrous metals following the introduction of emission control technologies.

PCBs, PCNs, PCDD/Fs, PAHs and Cl-PAHs in air and water particulate samples––patterns and variations

Methodology for the determination of biologically active polychlorinated biphenyls (PCBs), non- ortho PCBs, polychlorinated naphthalenes (PCNs), polychlorinated dibenzo- p-dioxins and dibenzofurans (PCDD/Fs), polycyclic aromatic hydrocarbons (PAHs) was used to investigate concentrations and patterns of certain chlorinated PAH (Cl-PAH) in source related samples using synthetic reference mixtures. Thus, in addition to the above mentioned compounds, mono-heptachlorosubstituted fluorenes, phenanthrenes/anthracenes and pyrenes/fluoranthenes (Cl-PAHs) were measured in vapour and particulate air samples from urban road tunnels, samples of settling particulate matter (SPM), and in bottom sediment samples from two point source locations (pulp and paper, and Mg-plant/Fe–Mn-smelter/chlor-alkali) and in the Baltic Sea. Concentrations in air samples followed: PAHs>PCBs>PCNs>non- ortho PCBs or Cl-PAHs>PCDD/Fs. SPM samples collected at increasing distance to the urban area of Stockholm showed: PAHs>PCBs>PCNs>PCDD/Fs>non- ortho PCBs or Cl-PAHs. For all compound groups there was a tenfold (Cl-PAHs fivefold) concentration decrease in SPM samples from highest levels in the urban water area to lowest levels at a distance of 26 km from city centre. PCB profiles of SPM showed similarities with combined profiles of Aroclor 1242 and 1254. PCN profiles of SPM showed similarities with combined profiles of Halowax 1099 and 1014. A correlation with concentration of all tested Cl-PAH and their corresponding parent PAH was found only for Cl-fluorene.

Biological activities of organic compounds adsorbed onto ambient air particles: comparison between the cities of Teplice and Prague during the summer and winter seasons 2000–2001

The capital of the Czech Republic, Prague, appears today to be one of the most polluted residential areas in the country, whereas air pollution in the Northern Bohemia region (the former “Black Triangle Region”) has substantially decreased during the last decade, especially with respect to the gaseous pollutant SO 2. This study evaluated the biological activities of complex mixtures of organic compounds adsorbed onto ambient air particles (PM10) collected during the summer and winter seasons of 2000–2001 at three monitoring sites—Teplice (TP), Prague–Smı́chov (PRG–SM) (city centre) and Prague–Libuš (PRG–LB) (suburban area). The following short-term in vitro assays with strikingly different endpoints were used: a bacterial mutagenicity test using the Salmonella typhimurium tester strain TA98 and YG1041, an acellular assay (CT DNA) combined with 32 P -postlabelling to evaluate DNA adduct-forming potency and the chick embryotoxicity screening test (CHEST). The results of the mutagenicity test with the YG1041 strain, the acellular genotoxicity (DNA adducts) and the embryotoxicity tests responded to the amount of eight carcinogenic polycyclic aromatic hydrocarbons (PAHs) analysed in the EOM (dichloromethane extractable organic matter) samples tested. Nevertheless, the biological effects of the EOM did not differ between locations. The highest biological activity of the ambient air in terms of organic compounds associated with particles (per unit volume of air) was seen in the Prague city centre during both summer and winter seasons. At this location, B[a]P concentration ranged from 0.1 to 8.9 ng/m 3 (mean 0.3 and 3.6 ng/m 3 for summer and winter seasons, respectively), 13 PAHs ranged from 11 to 343 ng/m 3 (mean 52 and 160 ng/m 3 for summer and winter seasons, respectively). Generally, using in vitro tests, higher ambient air activity was found in the winter season as compared with the summer season at all three monitoring sites (TA98 +S9, ∼4-fold; YG1041 −S9, ∼5-fold; YG1041 +S9, ∼8-fold; CT DNA +S9, ∼10-fold; CHEST, ∼10-fold; B[a]P, carcinogenic PAHs and total PAHs analysed, more than 10-fold). The different proportions of individual PAHs found in the summer and winter samples suggested traffic as a major emission source in the summer and, additionally, residential heating in the winter season at all three monitoring sites. The DNA adduct patterns resulting from the in vitro acellular assay also demonstrated similar major emission sources at all three locations. The study shows that particle-bound carcinogenic-PAH concentrations may be taken as an index for the biologically active (mutagenic, genotoxic, embryotoxic) components in air particulate samples. Therefore, high-quality monitoring data of carcinogenic PAHs may be useful for epidemiological studies of the impact of air pollution on the health of the population and for helping decision makers to improve our environment.

On simplex-based method for self-modeling curve resolution of two-way data

A method for self-modeling curve resolution (SMCR) of two-way data is proposed. This method comprises a new simplex-based procedure for directly determining the pure variables and an optimization algorithm to improve the resolution iteratively. First, it is demonstrated that with specific normalization, the two-way data points are contained in a simplex with the vertices constituted by the pure variables. This elucidates a precise geometry of an old discovery that two-way data points are bracketed by the pure variables. Second, a property of the simplex is given, which implies that the vertices of a simplex maximize a certain quadratic form over all the elements in the simplex. A procedure for determining pure variables in two-way data is then developed. Finally, an optimization algorithm to refine the resolution is suggested. The geometry of the algorithm is to locate a simplex that embraces the two-way data. With a good starting estimate that is as close as possible to the true pure profiles, the proposed method is expected to give improved resolution compared to traditional resolution techniques. The proposed method is evaluated using two simulated data sets and two data sets from hyphenated chromatography-diode array detection (HPLC-DAD) of polyaromatric hydrocarbon in air particle samples. The results reveal that the proposed method gives favorable resolution for the four data sets.

Particulate matter, PM 10 & PM 2.5 levels, and airborne mutagenicity in Chiang Mai, Thailand

Daily levels of particulate matter (PM) in the ambient air (PM 2.5 and PM 10) were measured in a northern city of Thailand (Chiang Mai) from March 1998 to October 1999. Twenty-four-hour air particulate matter samples were collected each day with Airmetric Minivol portable air samplers. Monthly averages of PM 2.5 from four stations in Chiang Mai varied from 15.39 to 138.31μg/m3 and 27.29 to 173.40μg/m3 for PM 10. The PM 2.5 annual average was 58.48mg/m3 and PM 10, 86.38μg/m3. Daily PM 2.5 (24h values) during the winter months in Chiang Mai frequently exceeded 200–300μg/m3. The maximum concentrations of PM 2.5 (24h average) in Chiang Mai air from December 1998 to April 1999 were 2.8-, 3.5-, 4.2-, 6.5- and 3.2-fold higher than the US Environmental Protection Agency (US EPA), PM 2.5, 24h standard of 65μg/m3. From May to October, the mean 24h levels of PM 2.5 and PM 10 were at acceptable levels. The data shows that during the winter season (December to March), levels of PM 2.5 and PM 10 in the Chiang Mai atmosphere are very high, and there may be significant health implications associated with these high concentrations. During the summer season, the fine particles were generally within the acceptable levels. To our knowledge, these are the first measurements of PM 2.5 to be reported for the city of Chiang Mai and they indicate considerable ambient fine particle exposures to the Chiang Mai population. In addition, dichloromethane extracts of airborne particulate matter PM 2.5 or PM 10 collected in the months of winter in the city of Chiang Mai were mutagenic to Salmonella typhimurium strain TA100 without metabolic activation. The mutagenicity appeared to track particle concentrations and increased in the presence of S9 mix.

Daily intake of aluminium by adult population of Mumbai, India

Electrothermal atomic absorption spectrophotometry (ET-AAS) has been used for the determination of Al in environmental and food samples with a detection limit of 0.3 ng ml −1. The reliability of estimation is assessed through the analysis of Standard Reference Materials (IAEA SRMs) of Soil-7, SL-3, SD-M2/TM and Hay (V-10). The results indicate that the average concentration of aluminium in air particulate samples is 5.3 μg m −3. The daily intake of Al by the adult population of Mumbai is 6.4 mg day −1.

Quantification of Polycyclic Aromatic Hydrocarbons and Aliphatic Hydrocarbons in Air Particulate Samples in Homes

Quantifications of 10 polycyclic aromatic hydrocarbons (PAHs) and 13 aliphatic hydrocarbons (AHs) ranging from n-C20 to n-C32 were reported in 17 homes and their adjacent outdoor environment in Hong Kong. It was found that PAHs were predominantly associated with PM_1.9, which contributed about 98 and 97% to the indoor and outdoor PM₁₀ PAHs, respectively. Also, indoor PAH levels seemed to be lower than outdoor PAH levels, both in the fine mode and in the coarse mode particles. The mean total PAH content in the indoor PM₁₀ was found to be 3.42 ng·m^–3 and it was 5.18 ng·m^–3 in the outdoor PM₁₀. It might demonstrate that there was no presence of indoor PAH sources in these homes. In contrast to PAH, AH levels were found to be higher indoors both in the fine mode and in the coarse mode particles. In addition, the concentrations of indoor and outdoor AH were significantly higher than their corresponding PAH levels. The mean total AH content in the indoor PM₁₀ was 104.42 ng·m^–3 and 94.06 ng·m^–3 in the outdoor PM₁₀. For PM_1.9, the total indoor AH content was 80.40 ng·m^–3 and the outdoor content was 70.55 ng·m^–3 on average. The distribution patterns of the indoor and outdoor AHs were similar, with maximum AH concentration varying from n-C27 to n-C31. The carbon preference indexes, which ranged from 0.84 to 2.62 for indoor and from 1.13 to 3.89 for outdoor environment, indicate the mixed origin of biogenic and anthropogenic sources in these homes.

Quantification of Polycyclic Aromatic Hydrocarbons and Aliphatic Hydrocarbons in Air Particulate Samples in Homes

Quantifications of 10 polycyclic aromatic hydrocarbons (PAHs) and 13 aliphatic hydrocarbons (AHs) ranging from n-C20 to n-C32 were reported in 17 homes and their adjacent outdoor environment in Hong Kong. It was found that PAHs were predominantly associated with PM1.9, which contributed about 98 and 97% to the indoor and outdoor PM10 PAHs, respectively. Also, indoor PAH levels seemed to be lower than outdoor PAH levels, both in the fine mode and in the coarse mode particles. The mean total PAH content in the indoor PM10 was found to be 3.42 ng.m-3 and it was 5.18 ng.m-3 in the outdoor PM10. It might demonstrate that there was no presence of indoor PAH sources in these homes. In contrast to PAH, AH levels were found to be higher indoors both in the fine mode and in the coarse mode particles. In addition, the concentrations of indoor and outdoor AH were sig nificantly higher than their corresponding PAH levels. The mean total AH content in the indoor PM10 was 104.42 ng.m-3 and 94.06 ng.m-3 in the outdoor PM 10. For PM1.9, the total indoor AH content was 80.40 ng.m -3 and the outdoor content was 70.55 ng.m-3 on average. The distribution patterns of the indoor and outdoor AHs were similar, with maximum AH concentration varying from n-C27 to n-C31. The carbon preference indexes, which ranged from 0.84 to 2.62 for indoor and from 1.13 to 3.89 for outdoor environment, indicate the mixed ori gin of biogenic and anthropogenic sources in these homes.

Beryllium: an easily scavenged metal ion in the environment

This study was specifically aimed to determine the levels of beryllium in environmental samples near the vicinity of the beryllium metal plant (BMP). Air particulate samples collected at the BMP site, in the non-monsoon and monsoon seasons, showed an average beryllium concentration of 0.3 and 0.1 ng m −3 respectively, where as rain water samples showed the beryllium values in the range of 0.01–0.2 ng ml −1. The suspended particulate matter (dust load) at the site studied was 570 and 250 μg m −3 in the non-monsoon and monsoon seasons respectively. The results obtained show that, in the environment, 80% of the total beryllium present is removed by rain.

A comparative study for results obtained using biomonitors and PM10 collectors in Sado Estuary

In 1996 a program was started, financed by the Environmental Ministry of Portugal and IAEA, aiming to study the inorganic atmospheric pollutant dispersion in Sado Estuary. Gent PM10 air samplers were used for air particulate matter sampling. Three sampling sites were chosen, forming a triangle around the fuel power station of Setúbal. Transplants of Parmelia sulcata Taylor were suspended in nylon bags within a rectangle 15 km wide and 25 km long on a 2.5×2.5 km grid. Two sets of four transplants were hung in each of the 47 locations, one set facing the wind and the other set opposing the wind. The transplants were suspended in December 1997 for a 1-year period; every 3 months, one transplant of each set was collected. Both lichen transplants and PM10 filters were analysed by INAA and PIXE. A comparative study of results obtained for the two sampling procedures is presented in this work.

Source Apportionment of Indoor PM2.5 and PM10 in Homes

A source apportionment analysis was performed using the elemental species concentrations of the air particulate samples collected in 8 homes from October 1999 to March 2000. It was based on a chemical mass balance approach using the source profiles from five common sources found in Hong Kong homes. These five sources were smoking, cooking, incense burning, human activities and outdoor contribution. Seventeen elements were analysed in the particulate samples collected by proton-induced X-ray emission. The results showed that cooking contributed on average 61.9% of the total indoor PM_2.5 in the 8 homes with 31.9% on average contributed from the outdoors. In contrast, the major contributor to the indoor PM₁₀ load was the outdoor contribution, which was 49.3% on average followed by human activities, which totalled 29.9% on average.

Bias in concentration estimates due to nonconstant flow rate during particulate air sampling.

Correction for a nonconstant flow rate during particulate air sampling is often done by taking the arithmetic average of the initial and final flow rates. This average is then used in concentration calculations as if the flow rate had been constant at that value during the entire sampling period. For long-lived activity this approach is reasonable, but for shorter-lived activity and longer sampling times the estimated concentrations can be biased low. This note examines the magnitude of this bias, and also provides expressions for estimating the concentration, given an observed count, assuming an exponential flow rate time-dependence. One expression uses an estimate of the exponential time-dependence, while another expression uses a linear approximation for the flow rate time-dependence. The parameters used in these expressions are estimated from the same initial and final flow rates used in the arithmetic average.

Ground-State Diffuse Reflectance and Laser-Induced Luminescence on the Evaluation of Total PAHs in Urban Air Particulate Matter from Rio de Janeiro City in Brazil

Ground-state diffuse reflectance and laser-induced fluorescence techniques were tested on the evaluation of total polycyclic aromatic hydrocarbons (PAHs) in unextracted and unfractionated airborne particulate matter. The total particulate PAH content estimated from these methods and from gas-chromatography in air particulate samples collected in the Rio de Janeiro city and for standard reference material (SRM) 1648, were compared. Ground-state diffuse reflectance proved to be by itself a good technique for estimating total PAH content in urban particulate matter, since results directly correlate with data obtained by conventional gas-chromatographic techniques. Laser-induced fluorescence is also an efficient method for low concentration estimates. Apparent deviations of the fluorescence response do occur due to black carbon interference and have to be taken into account. These surface optical methods showed to be fast, low cost, sensitive and useful as screening techniques, allowing field measurements.

Atmospheric dust loads and their elemental composition at a background site in India.

Air particulate samples collected during 1995-96 at a background site situated on the east coast of Thar Desert in Rajsthan State of India were analysed for atmospheric dust loads (Suspended Particulate Matter) and elemental composition. The values of SPM ranged from 9 microg M(-3) to 97 microg M(-3) with an average of 43 microg M(-3) except a few episodic values, which were 3 to 5 times higher than the average during summer months. The results for elemental composition of the particulate samples showed that the concentrations of anthropogenic toxic trace elements viz. Br, Cr, Pb, Sb, Se and Zn are lower by a factor of 2 to 10 as compared to urban areas. The high enrichment factors for anthropogenic elements viz. Br, Pb, Sb and Zn show an input from coal/wood fuel burning and vehicular pollution at the sampling site. The depletion of Si in SPM samples shows long distance transport of dust to the sampling site.

Residential indoor PM 10 and PM 2.5 in Hong Kong and the elemental composition

Indoor air particulate samples were collected in 34 homes and their adjacent outdoor environments in Hong Kong during the fall and winter seasons. It was found that the mean indoor PM 2.5 and PM 10 concentrations were 45.0 and 63.3 μg m −3, respectively. The corresponding mean outdoor levels were 47.0 and 69.5 μg m −3, respectively. The indoor particulate levels were found to be about 2–4 times higher than those in the homes in western countries where most are located in suburb areas with a much better ambient air quality. Pearson paired t-tests were conducted on the data and it was found that poor correlation was seen in the indoor and the outdoor particulate concentrations. This was probably due to the fact that windows were closed more often in the fall and winter seasons keeping the ventilation rate low, plus the factor that window type air conditioners were used commonly in Hong Kong, which again, constituted to a low air change rate. Both the indoor and the outdoor elemental compositions of the particulate samples collected in these 34 homes were identified by proton-induced X-ray emission analysis. Seventeen elements were identified. The mean inorganic elemental compositions in the indoor PM 2.5 and PM 10 samples were 6.4 and 10.2 μg m −3, respectively while those in the outdoor samples were 7.9 and 14.1 μg m −3, respectively. Enrichment factor analysis was performed and it was noted that those species existing in fine mode were highly enriched (bromine, lead, nickel, potassium, sulfur, vanadium and zinc) while those species existing in the coarse mode had their enrichment factors close to 1 (aluminum, calcium, iron, magnesium, silicon, sodium and titanium).