Submicron Particle Monitoring of Paving and Related Road Construction Operations

Abstract

This study identified activities and sources that contribute to ultrafine and other submicron particle exposure that could trigger respiratory symptoms in highway repair workers. Submicron particle monitoring was conducted for paving, milling, and pothole repair operations in a major metropolitan area where several highway repair workers were identified as symptomatic for respiratory illness following exposures at the 2001 World Trade Center disaster site. Exposure assessments were conducted for eight trades involved in road construction using a TSI P-Trak portable condensation particle counter. Direct readings near the workers’ breathing zones and observations of activities and potential sources were logged on 7 days on 27 workers using four different models of pavers and two types of millers. Average worker exposure levels ranged from 2 to 3 times background during paving and from 1 to 4 times background during milling. During asphalt paving, average personal exposures to submicron particulates were 25,000–60,000, 28,000–70,000, and 23,000–37,000 particles/ cm³ for paver operators, screed operators, and rakers, respectively. Average personal exposures during milling were 19,000–111,000, 28,000–81,000, and 19,000 particles/cm³ for the large miller operators, miller screed operators, and raker, respectively. Personal peak exposures were measured up to 467,000 and 455,000 particles/cm³ in paving and milling, respectively. Several sources of submicron particles were identified. These included the diesel and electric fired screed heaters; engine exhaust from diesel powered construction vehicles passing by or idling; raking, dumping, and paving of asphalt; exhaust from the hotbox heater; pavement dust or fumes from milling operations, especially when the large miller started and stopped; and secondhand cigarette smoke. To reduce the potential for health effects in workers, over 40 recommendations were made to control exposures, including improved maintenance of paver ventilation systems; diesel fume engineering controls; reduced idling; provision of cabs for the operators; and improved dust suppression systems on the milling machine.

[Supplementary materials are available for this article. Go to the publisher's online edition of Journal of Occupational and Environmental Hygiene for the following free supplemental resource: a PDF file containing recommendations for controlling fumes and dust during road repair and a report on an investigation of the New York City Department of Transportation road repair operations.]

Keywords:

• diesel
• milling
• paving
• road construction
• silica
• ultrafine

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ACKNOWLEDGMENTS

This study was made possible by the District Council 37 Health and Safety Unit of the American Federation of State, County and Municipal Employees. Funding for the study was from the COEM's normal operating expenses from the New York State Department of Health.