The NARSTO_EPA_SS_LOS_ANGELES_PM25_NITRATE data were collected between July 2001 and January 2002. At Claremont and Rubidoux (Los Angeles County, California), Cascaded Integrated Collection and Vaporization System for Particulate Nitrate (ICVS for Nitrate) was used in a mobile trailer to collect PM2.5 particulate nitrate data during July 11, 2001 to January 11, 2002. The ICVS for Nitrate measured PM2.5 particulate nitrate data that cover sizes from 0.1-2.5um in every 10 minutes.The overall objective of the Los Angeles Supersite in Southern California Particle Center and Supersite (SCPCS) is to conduct monitoring and research that contributes to a better understanding of the measurement, sources, size distribution, chemical composition and physical state, spatial and temporal variability, and linkages to health effects of airborne particulate matter in the Los Angeles Basin.The U.S. EPA Particulate Matter (PM) Supersites Program was an ambient air monitoring research program designed to provide information of value to the atmospheric sciences, and human health and exposure research communities. Eight geographically diverse projects were chosen to specifically address these EPA research priorities: (1) to characterize PM, its constituents, precursors, co-pollutants, atmospheric transport, and its source categories that affect the PM in any region; (2) to address the research questions and scientific uncertainties about PM source-receptor and exposure-health effects relationships; and (3) to compare and evaluate different methods of characterizing PM including testing new and emerging measurement methods.NARSTO (formerly North American Research Strategy for Tropospheric Ozone) is a public/private partnership, whose membership spans government, the utilities, industry, and academe throughout Mexico, the United States, and Canada. The primary mission is to coordinate and enhance policy-relevant scientific research and assessment of tropospheric pollution behavior; activities provide input for science-based decision-making and determination of workable, efficient, and effective strategies for local and regional air-pollution management. Data products from local, regional, and international monitoring and research programs are available.

NARSTO_EPA_SS_LOS_ANGELES_PARTISOL_DATA is the North American Research Strategy for Tropospheric Ozone (NARSTO) Environmental Protection Agency (EPA) Supersite (SS) Los Angeles Particulate Matter (PM) 2.5-10 Composition and Mass Data product. Data was collected using Partisol Model 2025-D samplers between late 2000 and late 2003 from sites at Downey, Claremont, Riverside, Rubidoux, and the University of Southern California (USC). Samples were collected episodically, frequently for a 24-hour per period, but in some cases multiple samples were collected over the course of a day. Element/metals, nitrate/sulfate ion, and mass concentration data were obtained. The Partisol is a dichotomous sequential multi-filter air sampler. It uses a virtual impactor to divide the air stream to facilitate the collection of fine (0.0-2.5um) and coarse (2.5-10.0um) particles onto a filter media over a pre-programmed collection period. The coarse fraction was analyzed using X-ray fluorescence and mass concentration analysis. Ion chromatography and mass concentration analyses were performed on the fine fraction. The overall objective of the Southern California Supersite (SCS) was to conduct research and monitoring that contributed to a better understanding of the measurement, sources, size distribution, chemical composition, physical state, spatial and temporal variability, and health effects of suspended PM in the Los Angeles Basin (LAB). Intensive aerosol measurements, well beyond the traditional PM2.5 mass, sulfate and nitrate concentrations, were conducted in several areas of the LAB. These included particle number concentrations, size distributions, and detailed PM chemical composition as a function of particle size. Sampling locations were chosen to provide wide geographical and seasonal coverage, including urban source sites and downwind receptor sites. The primary sampling facility, a mobile Particle Instrumentation Unit (PIU), was deployed to several locations to conduct a wide range of PM measurements. Sampling in each site lasted for 6-12 months. Intensive PM measurements were also conducted up and downwind of several freeways of the LAB, to characterize near-roadway exposure environments and to support several in vivo and in vitro health studies. The monitoring activities of the SCS were linked with toxicology studies in the LAB using a mobile PM Concentrator facility to investigate health effects associated with exposures to ultrafine, fine and coarse particles. Finally, the PIU facility was successfully used as a platform to develop, test, and evaluate numerous PM measurement instruments and sampling technologies, including several monitors for semi-continuous size fractionated mass and chemistry, personal PM exposure monitors, particle concentration technologies, and particle counting devices. NARSTO, which has since disbanded, was a public/private partnership, whose membership spanned across government, utilities, industry, and academe throughout Mexico, the United States, and Canada. The primary mission was to coordinate and enhance policy-relevant scientific research and assessment of tropospheric pollution behavior; activities provide input for science-based decision-making and determination of workable, efficient, and effective strategies for local and regional air-pollution management. Data products from local, regional, and international monitoring and research programs are still available.

The NARSTO_EPA_SS_LOS_ANGELES_APS_DATA were collected between December 2000 and September 2001. At several locations in Los Angeles County, California, a TSI Aerodynamic Particle Sizer (APS) was used in a mobile trailer to collect size characteristics of particles ranging from about 0.5 to 20 mm. Based on the time-of-flight principle, the APS measured particle count concentrations for 52 channels that cover sizes from 0.5 to 20 mm in every 15 minutes. Note that the first channel reports particle count concentrations for sizes < 0.523 mm.The overall objective of the Los Angeles Supersite in Southern California Particle Center and Supersite (SCPCS) is to conduct monitoring and research that contributes to a better understanding of the measurement, sources, size distribution, chemical composition and physical state, spatial and temporal variability, and linkages to health effects of airborne particulate matter in the Los Angeles Basin.The U.S. EPA Particulate Matter (PM) Supersites Program was an ambient air monitoring research program designed to provide information of value to the atmospheric sciences, and human health and exposure research communities. Eight geographically diverse projects were chosen to specifically address these EPA research priorities: (1) to characterize PM, its constituents, precursors, co-pollutants, atmospheric transport, and its source categories that affect the PM in any region; (2) to address the research questions and scientific uncertainties about PM source-receptor and exposure-health effects relationships; and (3) to compare and evaluate different methods of characterizing PM including testing new and emerging measurement methods.NARSTO (formerly North American Research Strategy for Tropospheric Ozone) is a public/private partnership, whose membership spans government, the utilities, industry, and academe throughout Mexico, the United States, and Canada. The primary mission is to coordinate and enhance policy-relevant scientific research and assessment of tropospheric pollution behavior; activities provide input for science-based decision-making and determination of workable, efficient, and effective strategies for local and regional air-pollution management. Data products from local, regional, and international monitoring and research programs are available.

The NARSTO_EPA_SS_HOUSTON_NO3_SO4_C_DATA files contain continuous measurements of PM2.5 nitrate, PM2.5 sulfate, and PM2.5 carbon collected during August 12, 2000 through November 5, 2001 at the Aldine, Deer Park, and LaPorte Houston Supersite monitoring locations. Nitrate measurements were collected using the R&P 8400N Method. Sulfate and carbon measurements were collected using the Prototype ADI Particulate Sulfate and Carbon Monitor Method.The Houston Supersite is one of several Supersites that was established in urban areas within the United States by the U.S. Environmental Protection Agency (EPA) to better understand the measurement, sources, and health effects of suspended particulate matter (PM). The overall goals were to characterize the composition and identify the sources of particulate matter in Southeastern Texas, to develop and test new methods for characterizing fine particulate matter, and to collect data on the physical and chemical characterization of fine particulate matter that can be used to support exposure and health effects studies.NARSTO (formerly North American Research Strategy for Tropospheric Ozone) is a public/private partnership, whose membership spans government, the utilities, industry, and academe throughout Mexico, the United States, and Canada. The primary mission is to coordinate and enhance policy-relevant scientific research and assessment of tropospheric pollution behavior; activities provide input for science-based decision-making and determination of workable, efficient, and effective strategies for local and regional air-pollution management. Data products from local, regional, and international monitoring and research programs are available.

The NARSTO_EPA_SS_LOS_ANGELES_SMPS_DATA were collected between December 2000 and February 2002. At Claremont, Downey, Riverside, Rubidoux (Los Angeles County, California), TSI Scanning mobility particle sizer (SMPS) was used in a mobile trailer to collect size characteristics of particles ranging from about 0.014 to 0.673 mm during December 8, 2000 to February 22, 2002. The SMPS measured particle count concentrations for 54 to 108 channels that cover sizes from 0.014 to 0.673 mm in every 15 minutes.The overall objective of the Los Angeles Supersite in Southern California Particle Center and Supersite (SCPCS) is to conduct monitoring and research that contributes to a better understanding of the measurement, sources, size distribution, chemical composition and physical state, spatial and temporal variability, and linkages to health effects of airborne particulate matter in the Los Angeles Basin.The U.S. EPA Particulate Matter (PM) Supersites Program was an ambient air monitoring research program designed to provide information of value to the atmospheric sciences, and human health and exposure research communities. Eight geographically diverse projects were chosen to specifically address these EPA research priorities: (1) to characterize PM, its constituents, precursors, co-pollutants, atmospheric transport, and its source categories that affect the PM in any region; (2) to address the research questions and scientific uncertainties about PM source-receptor and exposure-health effects relationships; and (3) to compare and evaluate different methods of characterizing PM including testing new and emerging measurement methods.NARSTO (formerly North American Research Strategy for Tropospheric Ozone) is a public/private partnership, whose membership spans government, the utilities, industry, and academe throughout Mexico, the United States, and Canada. The primary mission is to coordinate and enhance policy-relevant scientific research and assessment of tropospheric pollution behavior; activities provide input for science-based decision-making and determination of workable, efficient, and effective strategies for local and regional air-pollution management. Data products from local, regional, and international monitoring and research programs are available.

The NARSTO_EPA_SS_HOUSTON_TEXAQS2000_PM_FTIR measurement data consist of absolute absorbance areas for organonitrates, sulfate, aliphatic carbon and carbonyl compounds for size segregated particulate matter collected using a Herring Low Pressure Impactor (LPI). These data were collected during August and September 2000 at the Houston PM Supersite locations (LaPorte, HRM3, and Aldine) during the Texas Air Quality Study 2000 (TexAQS).The Houston Supersite is one of several Supersites that was established in urban areas within the United States by the U.S. Environmental Protection Agency (EPA) to better understand the measurement, sources, and health effects of suspended particulate matter (PM). The overall goals were to characterize the composition and identify the sources of particulate matter in Southeastern Texas, to develop and test new methods for characterizing fine particulate matter, and to collect data on the physical and chemical characterization of fine particulate matter that can be used to support exposure and health effects studies.NARSTO (formerly North American Research Strategy for Tropospheric Ozone) is a public/private partnership, whose membership spans government, the utilities, industry, and academe throughout Mexico, the United States, and Canada. The primary mission is to coordinate and enhance policy-relevant scientific research and assessment of tropospheric pollution behavior; activities provide input for science-based decision-making and determination of workable, efficient, and effective strategies for local and regional air-pollution management. Data products from local, regional, and international monitoring and research programs are available.

The NARSTO_EPA_SS_LOS_ANGELES_SMPS_DATA were collected between December 2000 and February 2002. At Claremont, Downey, Riverside, Rubidoux (Los Angeles County, California), TSI Scanning mobility particle sizer (SMPS) was used in a mobile trailer to collect size characteristics of particles ranging from about 0.014 to 0.673 mm during December 8, 2000 to February 22, 2002. The SMPS measured particle count concentrations for 54 to 108 channels that cover sizes from 0.014 to 0.673 mm in every 15 minutes.The overall objective of the Los Angeles Supersite in Southern California Particle Center and Supersite (SCPCS) is to conduct monitoring and research that contributes to a better understanding of the measurement, sources, size distribution, chemical composition and physical state, spatial and temporal variability, and linkages to health effects of airborne particulate matter in the Los Angeles Basin.The U.S. EPA Particulate Matter (PM) Supersites Program was an ambient air monitoring research program designed to provide information of value to the atmospheric sciences, and human health and exposure research communities. Eight geographically diverse projects were chosen to specifically address these EPA research priorities: (1) to characterize PM, its constituents, precursors, co-pollutants, atmospheric transport, and its source categories that affect the PM in any region; (2) to address the research questions and scientific uncertainties about PM source-receptor and exposure-health effects relationships; and (3) to compare and evaluate different methods of characterizing PM including testing new and emerging measurement methods.NARSTO (formerly North American Research Strategy for Tropospheric Ozone) is a public/private partnership, whose membership spans government, the utilities, industry, and academe throughout Mexico, the United States, and Canada. The primary mission is to coordinate and enhance policy-relevant scientific research and assessment of tropospheric pollution behavior; activities provide input for science-based decision-making and determination of workable, efficient, and effective strategies for local and regional air-pollution management. Data products from local, regional, and international monitoring and research programs are available.

NARSTO_EPA_SS_LOS_ANGELES_PARTISOL_DATA is the North American Research Strategy for Tropospheric Ozone (NARSTO) Environmental Protection Agency (EPA) Supersite (SS) Los Angeles Particulate Matter (PM) 2.5-10 Composition and Mass Data product. Data was collected using Partisol Model 2025-D samplers between late 2000 and late 2003 from sites at Downey, Claremont, Riverside, Rubidoux, and the University of Southern California (USC). Samples were collected episodically, frequently for a 24-hour per period, but in some cases multiple samples were collected over the course of a day. Element/metals, nitrate/sulfate ion, and mass concentration data were obtained. The Partisol is a dichotomous sequential multi-filter air sampler. It uses a virtual impactor to divide the air stream to facilitate the collection of fine (0.0-2.5um) and coarse (2.5-10.0um) particles onto a filter media over a pre-programmed collection period. The coarse fraction was analyzed using X-ray fluorescence and mass concentration analysis. Ion chromatography and mass concentration analyses were performed on the fine fraction. The overall objective of the Southern California Supersite (SCS) was to conduct research and monitoring that contributed to a better understanding of the measurement, sources, size distribution, chemical composition, physical state, spatial and temporal variability, and health effects of suspended PM in the Los Angeles Basin (LAB). Intensive aerosol measurements, well beyond the traditional PM2.5 mass, sulfate and nitrate concentrations, were conducted in several areas of the LAB. These included particle number concentrations, size distributions, and detailed PM chemical composition as a function of particle size. Sampling locations were chosen to provide wide geographical and seasonal coverage, including urban source sites and downwind receptor sites. The primary sampling facility, a mobile Particle Instrumentation Unit (PIU), was deployed to several locations to conduct a wide range of PM measurements. Sampling in each site lasted for 6-12 months. Intensive PM measurements were also conducted up and downwind of several freeways of the LAB, to characterize near-roadway exposure environments and to support several in vivo and in vitro health studies. The monitoring activities of the SCS were linked with toxicology studies in the LAB using a mobile PM Concentrator facility to investigate health effects associated with exposures to ultrafine, fine and coarse particles. Finally, the PIU facility was successfully used as a platform to develop, test, and evaluate numerous PM measurement instruments and sampling technologies, including several monitors for semi-continuous size fractionated mass and chemistry, personal PM exposure monitors, particle concentration technologies, and particle counting devices.NARSTO, which has since disbanded, was a public/private partnership, whose membership spanned across government, utilities, industry, and academe throughout Mexico, the United States, and Canada. The primary mission was to coordinate and enhance policy-relevant scientific research and assessment of tropospheric pollution behavior; activities provide input for science-based decision-making and determination of workable, efficient, and effective strategies for local and regional air-pollution management. Data products from local, regional, and international monitoring and research programs are still available.

The NARSTO_EPA_SS_LOS_ANGELES_APS_DATA were collected between December 2000 and September 2001. At several locations in Los Angeles County, California, a TSI Aerodynamic Particle Sizer (APS) was used in a mobile trailer to collect size characteristics of particles ranging from about 0.5 to 20 mm. Based on the time-of-flight principle, the APS measured particle count concentrations for 52 channels that cover sizes from 0.5 to 20 mm in every 15 minutes. Note that the first channel reports particle count concentrations for sizes < 0.523 mm.The overall objective of the Los Angeles Supersite in Southern California Particle Center and Supersite (SCPCS) is to conduct monitoring and research that contributes to a better understanding of the measurement, sources, size distribution, chemical composition and physical state, spatial and temporal variability, and linkages to health effects of airborne particulate matter in the Los Angeles Basin.The U.S. EPA Particulate Matter (PM) Supersites Program was an ambient air monitoring research program designed to provide information of value to the atmospheric sciences, and human health and exposure research communities. Eight geographically diverse projects were chosen to specifically address these EPA research priorities: (1) to characterize PM, its constituents, precursors, co-pollutants, atmospheric transport, and its source categories that affect the PM in any region; (2) to address the research questions and scientific uncertainties about PM source-receptor and exposure-health effects relationships; and (3) to compare and evaluate different methods of characterizing PM including testing new and emerging measurement methods.NARSTO (formerly North American Research Strategy for Tropospheric Ozone) is a public/private partnership, whose membership spans government, the utilities, industry, and academe throughout Mexico, the United States, and Canada. The primary mission is to coordinate and enhance policy-relevant scientific research and assessment of tropospheric pollution behavior; activities provide input for science-based decision-making and determination of workable, efficient, and effective strategies for local and regional air-pollution management. Data products from local, regional, and international monitoring and research programs are available.

The NARSTO_EPA_SS_LOS_ANGELES_MOUDI_DATA is the North American Research Strategy for Tropospheric Ozone (NARSTO) Environmental Protection Agency (EPA) Supersite (SS) Los Angeles Size-Fractionated Particulate Matter (PM) Composition - micro-orifice uniform deposit impactors (MOUDI) Data product. Data for this collection was collected between late 2000 and late 2003 from sites at Downey, Claremont, Riverside, Rubidoux, and the University of Southern California (USC). Samples were typically collected for a one-day period, but in some cases, duration was less than or more than one day. Element/metals, carbon, nitrate/sulfate ion, and mass concentration data were obtained. The MOUDI is a multiple stage inertial cascade impactor. At each stage, particles larger than the cut point of the stage are collected on the impaction plate while smaller particles pass through to the next stage. This continues through the cascade impactor until the smallest particles are collected on the after filter. At Downey, a size range of 10um to 0um was collected (10.0-2.5um, 2.5-1.0um, 1.0-0.32um, 0.32-0um). Most of the 10.0-2.5um size range samples were eliminated at Claremont, Riverside, Rubidoux, and USC because this size range was collected using the Partisol sampler. All samples were analyzed using X-ray florescence and mass concentration analysis at an independent laboratory. The overall objective of the Los Angeles Supersite in Southern California Particle Center and Supersite (SCPCS) was to conduct monitoring and research that contributes to a better understanding of the measurement, sources, size distribution, chemical composition and physical state, spatial and temporal variability, and linkages to health effects of airborne particulate matter in the Los Angeles Basin. The EPA PM Supersites Program was an ambient air monitoring research program designed to provide information of value to the atmospheric sciences, and human health and exposure research communities. Eight geographically diverse projects were chosen to specifically address these EPA research priorities: (1) to characterize PM, its constituents, precursors, co-pollutants, atmospheric transport, and its source categories that affect the PM in any region; (2) to address the research questions and scientific uncertainties about PM source-receptor and exposure-health effects relationships; and (3) to compare and evaluate different methods of characterizing PM including testing new and emerging measurement methods. NARSTO, which has since disbanded, was a public/private partnership, whose membership spanned across government, utilities, industry, and academe throughout Mexico, the United States, and Canada. The primary mission was to coordinate and enhance policy-relevant scientific research and assessment of tropospheric pollution behavior; activities provide input for science-based decision-making and determination of workable, efficient, and effective strategies for local and regional air-pollution management. Data products from local, regional, and international monitoring and research programs are still available.