One– and Three–Hour PM2.5 Characterization,Speciation, and Source Apportionment Using Continuous and Integrated Samplers

Ammonium nitrate and semivolatile organic compounds (SVOC) are significant components of fine particles in many urban atmospheres. These components, however, are not properly measured by current EPA accepted methods, such as the R&P TEOM monitor, due to loss of semivolatile material (SVM) from particles in the heated environment of the filter during sampling. The accurate determination of semivolatile material is important due to the possible effects of these species on human health, visibility, and global climate change. The concentration and composition of fine particulate material were determined using a combination of continuous and integrated samplers at the Brigham Young University–EPA Environmental Monitoring for Public Access and Community Tracking (BYU–EPA EMPACT) monitoring site in Salt Lake City, Utah over a six–day sampling period (30 January to 4 February) during the winter of 2001. Continuous samples were collected using a RAMS (total PM_2.5 mass), a TEOM monitor (nonvolatile PM_2.5 mass), an Aethalometer (elemental carbon), a TSI CPC (particle count), and a Nephelometer (light scattering by particles, b_sp). Fine particle composition and mass were determined on a three–hour basis using the PC–BOSS diffusion denuder sampler. Total PM_2.5 mass–determined with the RAMS agreed with constructed mass determined from the chemical composition measured in collocated PC–BOSS–integrated samples. Results from this study indicate that semivolatile material (ammonium nitrate and semivolatile organic compounds) is a significant component of fine particle mass. Semivolatile organic compounds were the major contributor to light scattering during the six–day sampling period. Semivolatile nitrate, but not organic material, was suggested to be hygroscopic by the nephelometric data. The majority of the SVM observed appeared to be secondary material formed from photochemical reactions of the organic and NO_x emissions from mobile sources and wood smoke combustion.     

Reconstructing Primary and Secondary Components of PM2.5 Composition for an Urban Atmosphere

Total 360 samples (of 8 h each) of PM_2.5 were collected from six sampling sites for summer and winter seasons in Kanpur city, India. The collected PM_2.5 mass was subjected to chemical speciation for: (1) ionic species (NH⁺ ₄, SO^2– ₄, NO^– ₃, and Cl^–), (2) carbon contents (EC and OC), and (3) elemental contents (Ca, Mg, Na, K, Al, Si, Fe, Ti, Mn, V, Cr, Ni, Zn, Cd, Pb, Cu, As, and Se). Primary and secondary components of PM_2.5 were assessed from speciation results. The influence of marine source to PM_2.5 was negligible, whereas the contribution of crustal dust was significant (10% in summer and 7% in winter). A mass reconstruction approach for PM_2.5 could distinctly establish primary and secondary components of measured PM_2.5 as: (1) Primary component (27% in summer and 24% in winter): crustal, elemental carbon, and organic mass, (2) Secondary component (45% in summer and 50% in winter): inorganic and organic mass, and (3) others: unidentified mass (27% in summer and 26% in winter). The secondary inorganic component was about 34% in summer (NH⁺ ₄: 9%; SO^2– ₄: 16%; NO^– ₃: 9%) and 32% in winter (NH⁺ ₄: 8%; SO²⁺ ₄: 13%; NO^– ₃: 11%). The secondary organic component was 12% in summer and 18% in winter. In conclusion, secondary aerosol formation (inorganic and organic) accounted for significant mass of PM _2.5 (about 50%) and any particulate control strategy should also include control of primary precursor gases.     

Size Distribution of Health-Relevant Trace Elements in Airborne Particulate Matter During a Severe Winter Stagnation Event: Implications for Epidemiology and Inhalation Exposure Studies

Size distributions for As, Cd, Bi, Br, Fe, Mn, S, Sb, Tl, K, V, Rb, elemental carbon (EC), organic carbon (OC), sulfate (SO ^2? ₄ ), chloride (Cl^?), and nitrate (NO^? ₃ ) were measured at Bakersfield and Modesto CA between 12/15/2000–01/07/2001. S and V size distributions were highly correlated with little diurnal variation suggesting that, during stagnant winter conditions, inhalation exposure and epidemiological studies can choose exposure/analysis times of several days during which population exposure will be relatively uniform. In contrast, the size distribution and temporal patterns of Fe are highly variable requiring more frequent measurements and shorter health analysis periods to adequately characterize exposure concentrations. K and Rb (tracers for wood smoke) exhibited nearly identical diurnal size distribution shifts (R ²  > 0.99) with smaller particles emitted at night and larger aged particles evident during the day. This pattern suggests that the health effects of fresh wood smoke could be studied through nighttime inhalation exposure experiments and aged wood smoke could be evaluated through daytime experiments. All of the components’ size distributions were consistent with production by combustion sources and/or secondary chemistry. Future inhalation exposure studies should use a combustion source to generate these particles. Lung deposition calculations predict that 32 ± 11% of PM deposition occurs in the pulmonary region, 61 ± 23% occurs in the respiratory region, and 6 ± 2% occurs in the tracheo-bronchial region for all components. Deposition patterns were highly correlated with PM _1.8 concentrations suggesting that exposure estimates can be developed with bulk filter samples during the current episode.     

A Shelter to Protect a Passive Sampler for Coarse Particulate Matter,PM10 − 2.5

This work designed and tested a shelter to protect a passive sampler for measuring coarse particulate matter, PM _{10 ? 2.5} . The shelter protects the sampler from precipitation and reduces the effects of wind on the deposition of particles to its collection surface. Six shelters were tested in a wind tunnel at three wind speeds: 2, 8, and 24 km hr ^?1 . Shelter performance was expressed as the ratio of PM _{10 ? 2.5} measured with the passive samplers to that measured with a filter-based dichotomous sampler. For most shelters, the PM _{10 ? 2.5} ratio averaged across wind speeds was well above one (2.4 to 8.5) and was generally dependent on wind speed. However, the PM _{10 ? 2.5} ratio for one shelter, the Flat Plates shelter, was 1.04 with substantially less effect on particle deposition from wind speed. Eight week-long field tests were conducted to compare PM _{10 ? 2.5} measured with a passive sampler installed in a Flat Plates shelter to that measured with a collocated filter-based dichotomous sampler. In these tests, the mean PM _{10 ? 2.5} ratio was 1.29. The linear relationship between PM _{10 ? 2.5} measured passively to that measured with the filter-based sampler had a Pearson correlation coefficient of 0.97 and was not significantly affected by the addition of weekly mean wind speed (p = 0.35). Although temperature was significant in this regression model (p = 0.02), it only improved the relationship marginally. The passive sampler in a Flat Plates shelter offers an inexpensive means to assess ambient PM _{10 ? 2.5} without on-site measurement of wind speed.     

Fine particles sampled at an urban background site and an industrialized coastal site in Northern France—Part 2: Comparison of offline and online analyses for carbonaceous aerosols

Particulate matter was sampled in Northern France during two summer and winter periods at both an urban background site (Douai, DO) and an industrialized coastal site (Grande-Synthe, GS). Ambient levels of particulate carbonaceous species and Polycyclic Aromatic Hydrocarbons (PAH) were measured by real-time measurements and via collection and analysis of offline filters (F). The comparison between online organic matter (OM) measured by an Aerosol Mass Spectrometer (AMS) and organic carbon (OC) determined by an offline thermal-optical method showed good linear trends in wintertime GS (r² = 0.82 while only 0.50 in summer), and DO (r² = 0.86 in summer and 0.92 in winter). However, significant differences were observed between analytical methods and sites with OC_AMS/OC_F ratios decreasing from 0.80 in DO during winter to ≈0.20 for GS in summer, suggesting that a large part of OM could be in the PM₁–PM_2.5 fraction. The simultaneous measurements of Black Carbon (BC) and Elemental Carbon (EC) concentrations in PM_2.5 were also well correlated at both sites with r² = 0.61–0.97 and slopes between 0.6 and 0.8. PAHs were analyzed in PM_2.5 and also measured online by AMS in PM₁. Their wintertime concentrations were highly correlated in DO (r² = 0.98) and to a lesser degree in GS (r² = 0.67). r² values determined for comparison between online and offline parameters (OC and PAHs) in GS were lower than in DO, probably due to a more complex aerosol composition and a higher variability of the physical and chemical properties resulting from the coastal situation and diversity of emission sources in the vicinity of GS.

Copyright © 2018 American Association for Aerosol Research     

PM1.0 and PM2.5 Characteristics in the Roadside Environment of Hong Kong

Daily mass concentrations of PM _1.0 (particles less than 1.0 μm in diameter), PM _2.5 (particles less than 2.5 μm in diameter), organic carbon (OC), and elemental carbon (EC) were measured from January through May 2004 at a heavily trafficked sampling site in Hong Kong (PU). The average concentrations for PM _1.0 and PM _2.5 were 35.9 ± 12.4 μ g cm ^{? 3} and 52.3 ± 18.3 μ g cm ^{? 3} . Carbonaceous aerosols were the dominant species in fine particles, accounting for ～ 45.7% of PM _1.0 and ～ 44.4% of PM _2.5 . During the study period, seven fine-particle episodes occurred, due to the influence of long-range transport of air masses from mainland China. PM _1.0 and PM _2.5 responded in similar ways; i.e., with elevated mass and OC concentrations in those episode days. During the sampling period, PM _1.0 OC and EC generally behaved similarly to the carbonaceous aerosols in PM _2.5 , regardless of seasonal variations and influence by regional pollutions. The low and relatively constant OC/EC ratios in PM _1.0 and PM _2.5 indicated that vehicular emissions were major sources of carbonaceous aerosols. PM _1.0 and PM _2.5 had the same dominant sources of vehicular emissions in winter, while in spring PM _2.5 was more influenced by PM _{1 ? 2.5} (particles 1–2.5 μ m in diameter) that did not form from vehicle exhausts. Therefore, PM _1.0 was a better indicator for vehicular emissions at the Roadside Station.     

Analysis of Aerosolized Particulates of Feedyards Located in the Southern High Plains of Texas

The objective of this study was to quantify, size, and examine the composition of particulates found in ambient aerosolized dust of four large feedyards in the Southern High Plains. Ambient air samples (concentration of dust) were collected upwind (background) and downwind of the feedyards. Aerosolized particulate samples were collected using high volume sequential reference ambient air samplers, PM ₁₀ and PM _2.5 , laser strategic aerosol monitors, cyclone air samplers, and biological cascade impactors. Weather parameters were monitored at each feedyard. The overall (main effects and estimable interactions) statistical (P < 0.0001) general linear model statement (GLM) for PM ₁₀ data showed more concentration of dust (μg/m ³ of air) downwind than upwind and more concentration of dust in the summer than in the winter. PM _2.5 concentrations of dust were comparable for 3 of 4 feedyards upwind and downwind, and PM _2.5 concentrations of dust were lower in the winter than in the summer. GLM (P < 0.0001) data for cascade impactor (all aerobic bacteria, Enterococcus spp, and fungi) mean respirable and non-respirable colony forming units (CFU) were 676 ± 74 CFU/m ³ , and 880 ± 119 CFU/m ³ , respectively. The PM ₁₀ geometric mean size (±GSD) of particles were analyzed in aerosols of the feedyards (range 1.782 ± 1.7 μm to 2.02 ± 1.74μm) and PM _2.5 geometric mean size particles were determined (range 0.66 ± 1.76 μm to 0.71 ± 1.71 μm). Three of 4 feedyards were non-compliant for the Environmental Protection Agency (EPA) concentration standard (150 μg/m ³ /24 h) for PM ₁₀ particles. This may be significant because excess dust may have a negative impact on respiratory disease.     

Source Apportionment of One-Hour Semi-Continuous Data Using Positive Matrix Factorization with Total Mass (Nonvolatile plus Semi-Volatile) Measured by the R&P FDMS Monitor

Positive matrix factorization (PMF) was used to elucidate sources of fine particulate material (PM _2.5 ) for a study conducted during July 2003 in Rubidoux, CA. One-h averaged semi-continuous measurements were made with a suite of instruments to provide PM _2.5 mass and chemical composition data. Total PM _2.5 mass concentrations (nonvolatile plus semi-volatile) were measured with a R&P filter dynamic measurement system (FDMS) and a conventional TEOM monitor was used to measure nonvolatile mass concentrations. Semi-volatile material (SVM) was calculated as the FDMS minus the TEOM determined PM _2.5 mass. PM _2.5 chemical species monitors included a R&P 5400 carbon monitor, an Anderson Aethalometer and a R&P 8400N nitrate monitor. Gas phase data including CO, NO ₂ , NO _x , and O ₃ were also collected during the sampling period. Two distinct PMF analysis were performed. In analysis 1, the TEOM was excluded from the analysis and in analysis 2, the SVM was excluded from the analysis. PMF2 was able to identify six factors from the data set and factors corresponding to both primary and secondary sources were identified. Factors were attributed to being primarily from automobile, diesel emissions, secondary nitrate formation, a secondary photochemical associated source, organic emissions and primary emissions. Good agreement was observed between the PMF predicted mass and the FDMS measured mass for both analyses.     

Major Source Categories for PM2.5 in Pittsburgh using PMF and UNMIX

An objective of the Pittsburgh Air Quality Study was to determine the major sources of PM_2.5 in the Pittsburgh region. Daily 24-hour averaged filter-based data were collected for 13 months, starting in July 2001, including sulfate and nitrate data from IC analysis, trace element data from ICP-MS analysis, and organic and elemental carbon from the thermal optical transmittance (TOT) method and the NIOSH thermal evolution protocol. These data were used in two source-receptor models, Unmix and PMF. Unmix, which is limited to a maximum number of seven factors, resolved six source factors, including crustal material, a regional transport factor, secondary nitrate, an iron, zinc and manganese factor, specialty steel production and processing, and cadmium. PMF, which has no limit to the number of factors, apportioned the PM_2.5 mass into ten factors, including crustal material, secondary sulfate, primary OC and EC, secondary nitrate, an iron, zinc and manganese factor, specialty steel production and processing, cadmium, selenium, lead, and a gallium-rich factor. The Unmix and PMF common factors agree reasonably well, both in composition and contributions to PM_2.5. To further identify and apportion the sources of PM_2.5, specific OC compounds that are known markers of some sources were added to the PMF analysis. The results were similar to the original solution, except that the primary OC and EC factor split into two factors. One factor was associated with vehicles as identified by the hopanes, PAH's, and other OC compounds. The other factor had strong correlations with the OC and EC ambient data as well as wood smoke markers such as levoglucosan, syringols, and resin acids.     

Twenty Four-Hour PC-BOSS Air-Monitoring Results from the NETL Fine-Particulate Sampling Site in Pittsburgh,Pennsylvania: An Annual Perspective

The concentration and composition of PM _2.5 from May to September of 2000 and monthly trends in ambient fine-particulate material concentrations from October 1999 through December 2000 at the National Energy Technology Laboratory's airmonitoring site in Pittsburgh are reported. Twenty four-hour integrated samples were collected using the Particle Concentrator-Brigham Young University Organic Sampling System (PC-BOSS), a multichannel integrated diffusion denuder sampler designed for routine determination of the chemical composition of ambient particulate matter. The fine-particulate pollutants determined were sulfate estimated as ammonium sulfate, nonvolatile organic material, semivolatile organic material lost from particles during sampling, elemental carbon, nitrate estimated as ammonium nitrate, including ammonium nitrate lost from particles during sampling and elemental content determined by PIXE (for a limited number of samples). Episodes with elevated sulfate and organic material (both semivolatile and nonvolatile) concentrations were seen throughout this period. For the purpose of this discussion, an episode was defined as all times when 3 h average TEOM monitor PM _2.5 concentrations exceeded 30 μg/m³. The use of estimated back-trajectories indicated that during the periods for which these elevated concentrations were observed, pollutants were transported predominantly from the Southwest from the Ohio River Valley to the sampling site. For days when fine particulate episodes occurred, back-trajectory computations were derived for time intervals for which PM _2.5 TEOM concentrations exceeded 30 μg/m³. However, for nonepisode days, back trajectories were computed over a 24 h period. Average PC-BOSS–constructed PM _2.5 concentration (including semivolatile components lost from particles during sampling) for the period from October 1999 through December 2000 was 19 μg/m ³ , excluding crustal material concentration.     

Inter- and Intra-Community Variability in Continuous Coarse Particulate Matter (PM10-2.5) Concentrations in the Los Angeles Area

Continuous coarse particulate matter (CPM, PM _10?2.5 ) concentrations were measured hourly at three different sites in the Los Angeles area from April 2008 through May 2009 as part of a larger study of the characteristics and toxicology of CPM. Mean hourly concentrations calculated seasonally ranged from less than 5 μg m ^–3 to near 70 μg m ^–3 at the three sites depending upon the CPM source variability and prevailing meteorology. Different diurnal concentration profiles were observed at each site. Correlation analysis indicates that CPM concentrations can generally be explained by wind-induced road dust re-suspension, particularly in drier seasons. CPM concentrations between the sites were not appreciably correlated and metrics used to assess variability between the sites—the coefficients of divergence—indicated that CPM concentrations were heterogeneous. The relative CPM contribution to observed PM ₁₀ concentrations varied by season and between sites. Additional concurrent CPM data available within a few km of the three sites indicate that intra-community variability can be on the same order as that observed for inter-community variability, although a similar analysis using PM ₁₀ data yielded reduced heterogeneity. The results indicate that accurate exposure assessment to CPM in the Los Angeles area requires measurements of CPM concentrations at different sites with higher temporal resolution than a single daily mean value.     

The Measurement of Ambient Bioaerosol Exposure

Monitoring of ambient bioaerosol concentrations through the characterization of outdoor particulate matter (PM) has only been performed on a limited basis in North Carolina (NC) and was the goal of this research. Ambient samples of PM _2.5 (fine) and PM _10?2.5 (coarse) were collected for a six-month period and analyzed for mold, endotoxins and protein. PM _2.5 and PM _10?2.5 concentrations of these bioaerosols were reported as a function of PM mass, as well as volume of air sampled. The mass of PM _2.5 was almost twice that of the PM _10?2.5 ; however, the protein and endotoxin masses were greater in the coarse than the fine PM indicating an enrichment in the coarse PM. The protein and mold results demonstrated a seasonal pattern, both being higher in the summer than in the winter. Except for an occasional excursion, the endotoxin data remained fairly constant throughout the six months of the study.     

A Novel Optical Instrument for Estimating Size Segregated Aerosol Mass Concentration in Real Time

A novel optical instrument has been developed that estimates size segregated aerosol mass concentration (i.e., PM ₁₀ , PM ₄ , PM _2.5 , and PM ₁ ) over a wide concentration range (0.001–150 mg/m ³ ) in real time. This instrument combines photometric measurement of the particle cloud and optical sizing of single particles in a single optical system. The photometric signal is calibrated to approximate the PM _2.5 fraction of the particulate mass, the size range over which the photometric signal is most sensitive. The electrical pulse heights generated by light scattering from particles larger than 1 micron are calibrated to approximate the aerodynamic diameter of an aerosol of given physical properties, from which the aerosol mass distribution can be inferred. By combining the photometric and optical pulse measurements, this instrument can estimate aerosol mass concentrations higher than typical single particle counting instruments while providing size information and more accurate mass concentration information than traditional photometers. Experiments have shown that this instrument can be calibrated to measure aerosols with very different properties and yet achieve reasonable accuracy.     

Measurement of Both Nonvolatile and Semi-Volatile Fractions of Fine Particulate Matter in Fresno,CA

An intensive sampling campaign was performed in Fresno, CA during December 2003 measuring fine particulate matter including both the semi-volatile and nonvolatile fractions of the aerosol. Both the newly developed R&P FDMS Monitor and a PC-BOSS have been shown to measure total PM _2.5 concentrations including semi-volatile nitrate and organic material. Good agreement was observed between the PC-BOSS and the R&P FDMS Monitor in this study with linear regression analysis resulting in a zero-intercept slope of 1.00 ± 0.02 and an R ² = 0.93. Several real-time measuring systems including the R&P Differential TEOM, the Met One BAMS, and a GRIMM Monitor were also employed and comparisons of total PM _2.5 mass were made with the R&P FDMS Monitor. Agreement among these various monitors was generally good. However, differences were sometimes seen. Reasons for observed differences in the real-time mass measurement systems are explained by the composition and complexity of the measured aerosol, most importantly the composition of semi-volatile material. A newly automated ion chromatographic system developed by Dionex was also field tested and compared to both R&P 8400N Nitrate and integrated PC-BOSS inorganic species measurements. Sulfate and nitrate determined by the Dionex and PC-BOSS systems agreed. However, nitrate measured by the 8400N was low during fog events compared to the other two systems.     

Chemical Characteristics of Fine Particles (PM1) from Xi'an,China

Daily mass concentrations of water-soluble inorganic (WS-i) ions, organic carbon (OC), and elemental carbon (EC) were determined for fine particulate matter (PM₁, particles < 1.0 μm in diameter) collected at Xi'an, China. The annual mean PM₁ mass concentration was 127.3 ± 62.1 μg m^–3: WS-i ions accounted for ～38% of the PM₁ mass; carbonaceous aerosol was ～30%; and an unidentified fraction, probably mostly mineral dust, was ～32%. WS-i ions and carbonaceous aerosol were the dominant species in winter and autumn, whereas the unidentified fraction had stronger influences in spring and summer. Ion balance calculations indicate that PM₁ was more acidic than PM_2.5 from the same site. PM₁ mass, sulfate and nitrate concentrations followed the order winter > spring > autumn > summer, but OC and EC levels were higher in autumn than spring. Annual mean OC and EC concentrations were 21.0 ± 12.0 μg m^?3 and 5.1 ± 2.7 μg m^–3 with high OC/EC ratios, presumably reflecting emissions from coal combustion and biomass burning. Secondary organic carbon, estimated from the minimum OC/EC ratios, comprised 28.9% of the OC. Positive matrix factorization (PMF) analysis indicates that secondary aerosol and combustion emissions were the major sources for PM₁.     

An Intercomparison of Measurement Methods for Carbonaceous Aerosol in the Ambient Air in New York City

Measurement methods for fine carbonaceous aerosol were compared under field sampling conditions in Flushing, New York during the period of January and early February 2004. In-situ 5- to 60-minute average PM _2.5 organic carbon (OC), elemental carbon (EC), and black carbon (BC) concentrations were obtained by the following methods: Sunset Laboratory field OC/EC analyzer, Rupprecht and Patashnick (R&P) series 5400 ambient carbon particulate monitor, Aerodyne aerosol mass spectrometer (AMS) for total organic matter (OM), and a two-wavelength AE-20 Aethalometer. Twenty-four hour averaged PM _2.5 filter measurements for OC and EC were also made with a Speciation Trends Network (STN) sampler. The diurnal variations in OC/EC/BC concentrations peaked during the morning and afternoon rush hours indicating the dominant influence of vehicle emissions. BC/EC slopes are found to range between 0.86 and 1.23 with reasonably high correlations (r > 0.75). Low mixing heights and absence of significant transported carbonaceous aerosol are indicated by the measurements. Strong correlations are observed between BC and thermal EC as measured by the Sunset instrument and between Sunset BC and Aethalometer BC. Reasonable correlations are observed among collocated OC/EC measurements by the various instruments.     

Characterization of Fine Particulate Emissions from Casting Processes

Fine particle (PM_2.5) emission rates and compositions from gray iron metal casting foundry were characterized for No-Bake molds poured at the Research Foundry located at Technikon, LLC (McClellan, CA). For each mold, PM_2.5 was collected for chemical analysis, and particle size distributions were measured by an Electrical Low Pressure Impactor (ELPI) to understand PM emissions during different part of the casting process. Molds prepared with phenolic urethane binders were poured with Class 30 gray cast iron at 1,427–1,480°C. PM_2.5 was collected from the pouring, cooling, and shakeout processes for each mold. Most of the PM_2.5 mass emitted from these processes was composed of carbonaceous compounds, including 37–67% organic carbon (OC) and 17–30% elemental carbon (EC). Oxides of aluminum (Al), silicon (Si), calcium (Ca), and iron (Fe) constituted 8–20% of PM_2.5 mass, and trace elements (e.g., K, Ti, Mn, Cu, Zn, and Pb) contributed 3–6%. Chemical abundances in PM were different between pouring and shakeout for each discrete mold. PM_2.5 mass emissions from pouring were 15–25% of the total from each discrete mold. Ultrafine particles (< 0.1 μm) contributed less than 1% of PM_2.5 mass, but nearly all of the particle numbers. Different mechanisms for pouring and shakeout result in variations in chemical abundances and particle size distributions. The highest PM_2.5 mass and number concentrations were observed when shakeout started. PM_2.5 size distributions in mass concentration during shakeout contained particles in the tail of coarse particles (1.6–2.5 μm) and a vapor condensation mode (0.65–1.6 μm). Flame conditions, vaporization, thermal decomposition of organic materials, and the variability of mold breakup during shakeout affect PM emission rates. A detailed chemical speciation for size-segregated PM samples at different process points needs to be conducted at full-scale foundries to obtain emission factors and source profiles applicable to emission inventories, source receptor modeling, and implementation of emission standards.     

Air Quality Profile of Inorganic Ionic Composition of Fine Aerosols at Two Sites in Mumbai City

The levels of PM ₁₀ , PM _2.5 , and NO ₂ were studied at a kerbsite and ambient site in Mumbai. Measurements were also made for eight inorganic ions (F ^? , Cl ^? , NO ₃ ^? , SO ^2? ₄ , Na ⁺ , K ⁺ , NH ₄ ⁺ , Ca ²⁺ , and Mg ²⁺ ) in the PM _2.5 fraction. During the study period, PM _2.5 , PM ₁₀ and NO ₂ levels ranged between 11–91, 18–125, and 8–64 μ g m ^{? 3} at a ambient site whereas at the kerbsite the ranges were 10–176, 21–189, and 4–55 μ g m ^?3 respectively. Average PM _2.5 values were 42 μ g m ^{? 3} at ambient and 69 μ g m ^?3 at the kerbsite. The measured ions accounted for about 50% of the PM _2.5 mass. Non-sea-salt (nss) sulfate contributed 91% and 85% of the ionic mass at the ambient and kerbsite sites respectively. Due to biomass sources of K, only about 5% of K ⁺ was from seas salt. The average equivalent ratio of NH ₄ ⁺ to nss- SO ² ₄ ^? , and NO ₃ ^? was over 1, indicating high source strength of ammonia.     

PM10/PM2.5/PM1 Data from a Trichotomous Sampler

ABSTRACT

As part of an effort to determine whether 1 μm or 2.5 μam is the better choice for a new fine particulate matter standard, Professor Virgil A. Marple of the University of Minnesota developed a high volume trichotomous (PM₁₀/PM_2.5 /PM₁) sampler. Two of these samplers were used to obtain particulate matter (PM) samples at a site located in Phoenix, Arizona, from May 1995 through October 1995. All filter samples were analyzed for mass concentrations and a few for elemental and chemical compositions. Relative fractions were determined for PM₁₀, PM_2.5, PM₁, PM_2.5–10, and PM_1–2.5. Calculations were made to evaluate how coarse and fine mode aerosol contributed to the intermediate size range. Results indicated that most of the PM₁₀ in Phoenix was coarse mode PM (windblown dust), which was also a primary contributor to PM₂₅.     

Fine particulate matter measurement and international standardization for air quality and emissions from stationary sources

This paper describes a number of global regulations dealing with very fine ambient particulate matter, PM_2.5 and PM₁₀ and the measurements aspects of PM_2.5 emission measurement methods for stationary sources, particularly of dilution techniques that promote simulation of atmospheric transformation of stack gases allowing for the use of the resulting near-ambient emission data in source apportionment and health risk studies, along with the current progress on international standardization of source PM_2.5 measurement methods.