The NARSTO_EPA_SS_ST_LOUIS_AIR_CHEM_PM_MET_DATA were obtained between April 11, 2001 and July 21, 2003 during the St. Louis - Midwest Supersite program.The overall goal of the St. Louis - Midwest Supersite was to conduct aerosol physical and chemical measurements needed by the health effects community, the atmospheric science community and the regulatory community to properly assess the impact of particulate matter exposure on human health and to develop control strategies to mitigate these effects. Metropolitan St. Louis is a major population center well isolated from other urban centers of even moderate size, and is impacted by both distant and local sources. Local industry includes manufacturing,refining, and chemical plants. St. Louis is climatologically representative of the country's eastern interior, affected by a wide range of synoptic weather patterns and free of localized influences from the Great Lakes, Ocean, Gulf, and mountains. It accordingly provides an ideal environment for studying the sources, transport, and properties of ambient particles.The initial data types included:1) 5-minute PM 2.5 black carbon (880 nm) and uv-absorbing carbon (370 nm) measured by a Magee Scientific Aethalometer (Model AE-21).2) 1-hour PM 2.5 elemental carbon and blank-corrected organic carbon from semicontinuous thermo-optical analysis by the ACE-ASIA method.3) 24-hour PM 2.5 elemental carbon and organic carbon (both blank-corrected) from integrated filter with offline thermo-optical analysis by the ACE-ASIA method.4) 30-minute PM 2.5 metal composition from samples collected with a Semicontinuous Elements in Aerosol Sampler (SEAS) II.5) 5-minute meteorological data (wind, temperature, RH, solar radiation, atmospheric pressure, and precipitation) measured with a Climatronics anemometer, wind vane, thermocouple, lithium chloride sensor, pyranometer, barometer, and tipping bucket.6) 24-hour PM 1.0 filter mass concentration measured by sharp cut cyclone and gravimetric analysis.7) 1-hour PM 2.5 mass measured by an Andersen Continuous Ambient Mass Monitoring System (CAMMS).8) 24-hour PM 2.5 and PM 10 filter mass by Harvard Impactors and laboratory gravimetric analysis.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_SOS_SC_UPSTATE_PM25_COMPOSITION data were collected during July 2001 and January of 2002 to elucidate the seasonal variability of the aerosols. Samples were collected at a rural location in South Carolina, beginning and ending at midnight in order to associate each sampling event with a calendar day. In all, 40 samples per month were collected (including blanks).The purpose of the study was to determine experimentally the concentration and chemical composition of fine particulate matter (PM2.5, particles with a diameter less than 2.5 um) in South Carolina. The collection of PM2.5 samples on Teflon filters was carried out using a cyclone-based system. Ion chromatography analysis for anions and cations was performed, as well as x-ray fluorescence (XRF) analysis for crustal metals. PM2.5 samples on quartz filters were also collected in order to determine the organic and elemental carbon (EC/OC) particle concentration.The average concentration for PM2.5 during July of 2001 was 20.85 mg/m3. The major components of the aerosol were organic compounds (38.5%) and sulfates (34.7%). During January of 2002, the average concentration for PM2.5 was 9.4 mg/m3. Again, the major components of the aerosol were organic compounds (64.1%) and sulfates (21.9%).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_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.

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_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.

NARSTO_SOS99NASH_G-1_AIR_CHEMISTRY_DATA is the North American Research Strategy for Tropospheric Ozone (NARSTO) SOS99 Nashville Department of Energy (DOE) G-1 Air Chemistry Data product. Data was collected via the G-1 aircraft deployed during the 1999 campaign to make measurements within the Nashville urban plume. These in situ, semi-Lagrangian measurements, in conjunction with surface-based observations independently made at the Polk Building and at the Cornelia Fort site, allowed quantification of the following: a) ozone production/loss rates, b) ozone production efficiency and c) NOx loss rates within this plume. Mechanical problems with the G-1 aircraft precluded making additional measurements. North American Research Strategy for Tropospheric Ozone (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_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_DMA_DATA measurements consist of aerosol size distributions and number concentrations collected in Houston, Texas, beginning in August 2000 and ending in November 2001. Data were collected at two sites throughout this period (Aldine and HRM3), and a third instrument sampled at two sites (La Porte: Aug-Sep 2000; Deer Park: Sep 2000-Oct 2001). These measurements were collected as part of the EPA Supersite program. High-flow differential mobility analyzers (DMAs) were used to collect these data.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.

NARSTO_PAC2001_SUMAS_MTN_GAS_PM_MET_DATA was obtained between August 13 and September 5, 2001 during the Pacific 2001 Air Quality Study (PAC2001). Measurements were collected at the Sumas Eagle Ridge (SER) site. The SER site was located at 49.05166 N and -122.24666 W, at 300 m above sea level (a.s.l.) and approximately 250 m above the surrounding valley floor. The site was in a forest clearing of about 85 - 95m2 on top of a concrete-covered reservoir and surrounded by a mixture of coniferous and deciduous trees. The shortest distance from the site to residential area was about 1 km and was about 3 km to the edge of city of Abbotsford and the nearby major traffic route of Highway 1 in the valley floor. About 3 km to the south of the site, where the elevation drops to about 50 m a.s.l. in the valley floor, NH3 emissions are strong from agricultural sources, and their impact of particle formation and hence the visibility reduction is expected to be significant. Because the site was elevated, the boundary layer did not reach the site each day until midmorning, as indicated by NO and CO. Hence, it was a unique site to study changes in gas and particle chemistry from light to dark hours, the nighttime chemistry and the interaction between biogenic emissions and urban pollution. The site was chosen also to characterize particles for optical, chemical and physical properties since PM in this area of the valley appears to be optically different from those typically observed over the urban areas in Vancouver. The main objectives were to: obtain mass and optical closure in order to better attribute aerosol types and sources to the issues of PM and visibility, and to determine the contribution of non-volatile organic compounds (VOCs), biogenic VOCs, and NH3 to particle mass. Gas phase measurements included oxidant related species: O3, NOx , total and speciated NOy, H2O2, CO, SO2, VOCs, including terpenes and some of their oxidation products, carbonyls, and NH3. Nighttime NO3 was measured at a site near this main site by differential optical absorption spectroscopy. Particle chemical characterization measurements included size-distributed mass, inorganic composition, and organic carbon and elemental carbon (using quartz filters and thermal optical transmittance measurements from 0:05 to 18 mm AD. High-time resolution measurements using an AMS were carried out for the last 5 days during this period, covering the size distribution of inorganic and organic species from 0.06 to 0:7 mm AD. Carbon isotope and detailed speciation of organic carbon in particles 2:5 mm were done on high volume samples on quartz filters that were collected twice daily. Continuous mass measurements for particles 10 mm were made using a tapered element oscillating microbalance (TEOM) that operated at 50C. Particle physical measurements were made to characterize the particle evolution at this site. This included concentration of particles 40:015 mm, number size distribution measurements from 0.003 to 0:20 mm using ultrafine Dynamic mechanical analysis (DMAs). Standard meteorological measurements were carried out at this site during the measurement period. The Pacific 2001 Air Quality Study (PAC2001) was conducted from 1 August to 31 September 2001 in the Lower Fraser Valley (LFV), British Columbia, Canada. The study consisted of individual research projects organized to address several issues on ambient particulate matter and ozone that are important to policy makers. A special issue of Atmospheric Environment [Vol. 38(34), Nov 2004] described specific study objectives (Li, 2004) and presented a series of results papers from the field study. The ground sampling sites during the study were Cassiar Tunnel, Slocan Park, Langley Ecole Lochiel, Sumas Eagle Ridge, and Golden Ears Provincial Park. Aloft measurements were taken from a Convair 580 and a Cessna 188. Selected measurement data were compiled for each site and aircraft and are archived as site-specific data sets