DESCRIPTION (provided by principal investigator): Project Summary Excessive noise in the urban setting is a topic of increasing public health concern. Mass transit, and aging subway systems, in particular, are prime sources of urban noise. Yet the risk associated with subway noise is understudied and risk assessment data on subway-related noise exposure are exceptionally limited. As an important first step in our research team's trajectory of assessing urban noise associated with mass transit, we conducted environmental noise sampling of the NYC subway system. Noise levels inside subway cars and on subway platforms were in excess of standard recommended levels;for some of the levels measured, the recommended community exposure limits are as little as 1.5min per 24hrs. To estimate the ridership's risk of potential noise exposure, which is a function of both noise level and exposure duration, we recently conducted a feasibility study. Using a modified street intercept recruitment methodology, preliminary data were obtained from nearly 1100 attendees at neighborhood street fairs. The sample was diverse (26 percent were racial/ethnic minorities, mean age was 43yrs, range 18-89yrs) and representative of NYC census data. 27 percent of the sample reported no subway ridership;for participants that did ride the subways, the mean duration (time spent on platforms and inside subway cars) was 1.98 hrs/day, for an average of 5 days/week (max 7.0 hrs/day, median 1.75 hrs/day, mode 1.20 hr/day). When combined with pilot measurements of subway noise, the preliminary mean subway exposure duration of 1.98 hrs yields a 24-hr average exposure level that substantially exceeds the guidelines for community noise exposure published by the U.S. E.P.A. even without considering other sources of exposure. To characterize the contribution of subway noise to total noise exposure in an urban population, we propose a two-year, four-phase, transdisciplinary risk assessment study of NYC community members. The purpose of this R21 exploratory study is fourfold: (1) to characterize subway and other highly variable mass transit environments using time-integrated dosimetry, (2) to estimate current subway-related noise duration among a large (N=5000) sample of diverse NYC community members representing a range of subway ridership (from none to extensive) using a self-administered questionnaire, (3) to determine total (combined) noise exposure from three major sources (subway and other mass transit related, work and leisure-time) and to determine the contribution of subway noise to total noise exposure, and (4) to compare these exposures to recommended allowable community-level exposure levels. Using validated instruments, duration of work and leisure time activities data will be obtained from questionnaires and noise levels for the various work/leisure activities will be obtained from well validated peer reviewed documents. The findings from this study will not only provide important new information but also the context for the design of urban noise studies which will have translational research implications for public health policy and practice. PUBLIC HEALTH RELEVANCE: This study will determine the risk of excessive noise exposure associated with subway and other mass transit- ridership in a population of urban New York City community members. The population at potential risk in NYC alone is in excess of 3 million riders;nationwide, more than 10 million riders use subway systems that are 75 years old or greater. This study has translational implications for public health policy and practice.