Real-time Carbon and Sulfate Measurements from the MANE-VU Rural Aerosol Intensive Network (RAIN): Design, Methods and Early Data

A rural, high elevation monitoring network of aerosol and visibility related parameters has been recently deployed in the Northeast U.S. under the Mid-Atlantic and Northeast Visibility Union (MANE-VU) regional haze planning organization (RPO). This network is designed to provide detailed characterization of transported pollution with both a visibility and fine particle focus. The initial network has three high-elevation (700-2500') sites with detailed PM and visibility-related measurements. The sites cover a wide geographic area from near the Ohio River valley to Acadia National Park, allowing an assessment of a range of aerosol types ("fresh" vs. aged secondary aerosols) and their precursor gases. Aerosol measurements are made yearround with highly time-resolved (1-2 h) methods, providing enhanced insight into regional aerosol generation and source characterization, and factors that drive short-term visibility. These data will also be used for aerosol model performance evaluation and development. Hourly parameters measured in this network include: PM2.5, sulfate, EC/OC, light scattering, trace SO2 and CO, ozone, surface meteorology, and visual scene images. IMPROVE third-day 24-hour integrated measurements for carbon, ions and PM2.5 are made at all sites. The network is a multi-year project, with routine operations being integrated into participating state agency’s networks. The sites are located in a SW-NE line: Frostburg - western MD (near-source), Mohawk Mt. - northwest CT (mixed-source), and Acadia NP (far-source). This network is the first long-term deployment of the Thermo Electron continuous sulfate and Sunset Laboratories carbon analyzers at routine state agency monitoring sites; these methods are representative of the new breed of mature continuous speciation methods now available. This paper focuses on method descriptions, initial data, and operational issues from these two methods. A simple PM2.5 reconstruction using only sulfate and carbon is shown to be a useful diagnostic tool for instrument performance.