NARSTO EPA Supersite (SS) Houston, Rapid Single-Particle Mass Spectrometer (SPMS) Data

NARSTO_EPA_SS_HOUSTON_RAPID_SPMS_DATA is the North American Research Strategy for Tropospheric Ozone (NARSTO) Environmental Protection Agency (EPA) Supersite (SS) Houston, Rapid Single-Particle Mass Spectrometer Data. This product contains individual aerosol particles which were sized and analyzed using a Rapid Single-particle Mass Spectrometer (RSMS) in Houston during the summer of 2000. RSMS aerodynamically focuses one particle size at a time to the source region of a mass spectrometer and employs a 193 nm excimer laser to desorb and ionize the particle components. The ions are analyzed in a single time-of-flight mass spectrometer and the spectrum is digitally recorded. Spectra are only saved if the ion peak in the spectrum is above a threshold level. Background spectra were determined and flagged. Particle size scans were initiated periodically, and each size was sampled until 30 particle hits were obtained, unless the sampling time became excessive. Aerodynamic particle sizes ranged from about 40 to 1300 nm and were partitioned into nine discrete size classes logarithmically spaced, roughly, over the range.

Single particle data are valuable because they:
- are collected and analyzed real time so have excellent temporal resolution,
- enable assessment of particle-to-particle composition variations (external mixing properties),
- allow for easy identification of key particle sources since the particles retain source characteristics.

The data resulting from these measurements consisted of an aerodynamic particle size and a positive mass spectrum of the components for each particle, along with the date and time of measurement and other incidental measurement parameters such as the laser pulse energy. Support for RSMS measurements was provided by the EPA Supersite program and additional funding from the EPA. The Houston Supersite is one of several Supersites that was established in urban areas within the United States by the 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 PM in Southeastern Texas, to develop and test new methods for characterizing fine PM, and to collect data on the physical and chemical characterization of fine PM that can be used to support exposure and health effects studies.

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.

NARSTO_EPA_SS_HOUSTON_RAPID_SPMS_DATA 即北美对流层臭氧研究计划（North American Research Strategy for Tropospheric Ozone，NARSTO）-美国环境保护署（Environmental Protection Agency，EPA）超级站点（Supersite，SS）休斯顿快速单粒子质谱仪数据集。本数据集包含2000年夏季于休斯顿地区，经快速单粒子质谱仪（Rapid Single-particle Mass Spectrometer，RSMS）完成粒径分选与成分分析的单颗气溶胶粒子数据。RSMS可将单一粒径的粒子气动聚焦至质谱离子源区，并采用193 nm准分子激光对粒子组分进行解吸与电离。离子通过单次飞行时间质谱仪完成分析，质谱信号经数字化记录。仅当谱图中离子峰强度高于阈值时，该谱图才会被保存。研究人员已完成本底谱图的测定与标记。粒子粒径扫描按周期启动，每个粒径档位均采样至获得30次粒子信号命中，除非采样耗时过长。气动粒径范围约为40~1300 nm，并在该区间内以对数间隔划分为9个离散粒径档位。

单粒子数据具有极高的应用价值，原因在于：
- 采用实时采集与分析模式，具备优异的时间分辨率；
- 可实现粒子间成分差异的评估（即外混合特性）；
- 能够便捷识别主要粒子源，因为粒子保留了其排放源的特征信息。

本次测量得到的数据包含每颗粒子的气动粒径与正离子模式下的组分质谱，同时附带测量日期、时间以及其他附带测量参数，例如激光脉冲能量。快速单粒子质谱仪测量工作由EPA超级站点项目提供支持，并获得了EPA的额外经费资助。休斯顿超级站点是EPA在美国城市地区设立的多个超级站点之一，旨在深入理解悬浮颗粒物（Particulate Matter，PM）的测量方法、排放源与健康效应。本项目的总体目标包括：表征德克萨斯州东南部地区细颗粒物的组分并识别其排放源，开发并测试细颗粒物表征的新方法，以及收集细颗粒物物理与化学特性数据，用于支撑暴露评估与健康效应相关研究。

已解散的NARSTO是一项公私合营的伙伴计划，其成员涵盖墨西哥、美国与加拿大的政府机构、公用事业单位、工业界与学术界。该计划的核心使命是协调并强化与政策相关的对流层污染行为科学研究与评估工作，其产出可为基于科学的决策制定以及制定本地、区域大气污染治理的可行、高效且有效的策略提供依据。当前，来自本地、区域及国际监测与研究项目的数据产品仍可获取。