Noise Pollution in the United States

Day-night average noise and average nighttime noise at the census tract level in the contiguous United States. Noise levels represent an average summer day between 2000-2014. To view an interactive map open this url in your browser:

About the interactive map:

The noise map displays census tract level estimates of noise, categorized as below, slightly exceeding, and exceeding the U.S. EPA day-night average sound level (Ldn) limit of <55 decibels (dB). Points (census tract centroids) display values in the small-scale map and census tract boundaries appear when the user zooms in to a specific city. Available on the large-scale (zoomed in) map, users can click a specific census tract and see which noise category the tract falls into: (1) Ldn: low = <55 dB; medium = 55-58 dB; and high = 58+ dB; and (2) Median nighttime noise: low = < 40 dB; medium = 40-43 dB; and high = 43+ dB.

A bit about the noise data:

The noise exposure data was obtained from a geospatial model of environmental sound levels derived from empirical acoustical data and modeling of land features (topography, climate, hydrology, and anthropogenic activity) (Mennitt and Fristrup 2016). We have previously used this model in a nationwide environmental justice analysis (Casey et al. 2017). Noise exposures were estimated from a random forest model that utilizes a tree-based machine learning algorithm to combine spatial data with over 1.5 million hours of long-term noise measurements at 492 urban and rural sites in the contiguous U.S. from 2000–2014 to produce ambient sound estimates at a 270m resolution. Complete information on explanatory variables in the model are provided by the National Park Service (Sherrill 2012). The model has been shown to perform well under cross-validation tests, with a median absolute deviation of 1.7 dB in urban areas (Casey et al. 2017). The main map provides low, medium, and high cut-points based on cross-sectional day-night average sound (Ldn), 24-hour average noise with penalties added for evening and nighttime noise. We also display average nighttime noise, L50, night, where night is defined as 22:00–7:00 hours with low, medium, and high cut-points that correspond to the levels below, slightly exceeding, and exceeding the World Health Organization (WHO) recommended nighttime noise level of 40 dB. The WHO recommends nighttime Leq fall below 40 dB. They describe 40 dB as the lowest observable adverse effect level for nighttime noise (WHO 2011).

Previous research:

Drs. Casey, Morello-Frosch, and colleagues recently identified large racial/ethnic and socioeconomic disparities in noise pollution across the United States (Casey et al. 2017). We do not yet know whether disproportionate noise exposure among vulnerable populations can help explain health disparities. In a current study, we combine our nationwide noise model, American Community Survey data, and the 500 Cities Health Data to evaluate associations between nighttime and 24-hour noise exposures and census tract level prevalence of hypertension, poor sleep, and poor mental health.

Funders: This research is based upon work supported by the Urban Institute through funds provided by the Robert Wood Johnson Foundation. We thank them for their support but acknowledge that the findings and conclusions presented in this report are those by the author(s) alone and do not necessarily reflect the opinions of the Urban Institute or the Robert Wood Johnson Foundation.




Water Equity Science Shop (WESS)







WESS is a community-academic partnership that conducts research and multi-level public health actions tot address the health risks associated with drinking water contamination among California residents in rural, agricultural, and socioeconomically disadvantaged communities that are served by small drinking water systems and private wells that fall outside the purview of drinking water regulations and monitoring requirements.

Funder: NIEHS Superfund Program, Community Engagement Core




Chemicals in Our Bodies








Chemicals in Our Bodies is a San Francisco-based pregnancy cohort study (N=502) that is part of UCSF’s PEEC Children’s Environmental Health Center that is examining the fetal growth and developmental impacts of environmental chemicals, exposure to chronic psychosocial stress, and their potential interactive effects.

Funders:  NIEHS Children’s Environmental Health Center, EPA-STAR, NIEHS R01, NIH Environmental Health Influence on Child Health Outcomes (ECHO) Program).




Women Worker Biomonitoring Collaborative



The Women Worker Biomonitoring Collaborative is the first biomonitoring study to compare exposures to potential breast carcinogens and other endocrine disrupting compounds between women firefighters, nurses and office workers in San Francisco, CA.  In addition to using targeted and non-targeted biomonitoring methods, I am evaluating the impact on biomarkers of early effect (i.e. thyroid hormone disruption and telomere length) of chemical exposures and workplace stress.

Funder:  California Breast Cancer Research Program




Climate Justice Initiative








The Climate Justice Initiative seeks to assess and temporally track the equity implications and potential co-benefits of California’s diverse climate change laws, specifically greenhouse gas (GHG) mitigation activities from stationary and transportation sources that are regulated under California’s GHG reduction programs. 

Funders:  CA Office of Environmental Health Hazard Assessment, Energy Foundation, CA Air Resources Board




Health Impacts of Oil and Gas Development








Health Impacts of Oil and Gas Development is a project to assess potential health and equity impacts of oil and gas extraction activities in California.

Funders: California Air Resources Board, 11th Hour Project




Ethics of Report-back in Chemical Biomonitoring






Ethics of Report-back in Chemical Biomonitoring is a project that seeks to advance study participants’ right-to-know and right-to-act to reduce their exposures to environmental chemicals through ethical, accessible and novel strategies for communicating personal exposure results.

Funders: National Institute of Environmental Health Sciences (NIEHS), National Science Foundation (NSF), California Breast Cancer Research Program, California Wellness Foundation