Data used in these analyses was obtained from publically-available sources, specifically the EPA's AirNow website (https://www.epa.gov/outdoor-air-quality-data). The dataset provided includes the subset of data from AirNow that was used in our analyses. This dataset is associated with the following publication: Dickerson, A., A. Benson, B. Buckley, and E. Chan. Concentrations of individual fine particulate matter components in the United States around July 4th. Air Quality, Atmosphere & Health. Springer Netherlands, NETHERLANDS, 1-10, (2016).

This web service contains the following layer: PM25_2014_SesonReview_35CBSA. Full FGDC metadata records for each layer may be found by clicking the layer name at the web service endpoint (available through the online link provided above) and viewing the layer description.

This dataset represents the raw hourly, daily, and design value data used in this article. All of the data was downloaded from EPA's Air Quality System (AQS) with the exception of the list of near-road sites which was downloaded from https://www.epa.gov/amtic/no2-monitoring-near-road-monitoring. The datasets are named based on their AQS parameter code (see https://www.epa.gov/aqs/aqs-code-list), averaging time, and years included. Citation information for this dataset can be found in the EDG's Metadata Reference Information section and Data.gov's References section.

This dataset represents the raw hourly, daily, and design value data used in this article. All of the data was downloaded from EPA's Air Quality System (AQS) with the exception of the list of near-road sites which was downloaded from https://www.epa.gov/amtic/no2-monitoring-near-road-monitoring. The datasets are named based on their AQS parameter code (see https://www.epa.gov/aqs/aqs-code-list), averaging time, and years included. Citation information for this dataset can be found in the EDG's Metadata Reference Information section and Data.gov's References section.

The NARSTO_EPA_SS_HOUSTON_TEXAQS2000_PM_FTIR measurement data consist of absolute absorbance areas for organonitrates, sulfate, aliphatic carbon and carbonyl compounds for size segregated particulate matter collected using a Herring Low Pressure Impactor (LPI). These data were collected during August and September 2000 at the Houston PM Supersite locations (LaPorte, HRM3, and Aldine) during the Texas Air Quality Study 2000 (TexAQS).The Houston Supersite is one of several Supersites that was established in urban areas within the United States by the U.S. Environmental Protection Agency (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 particulate matter in Southeastern Texas, to develop and test new methods for characterizing fine particulate matter, and to collect data on the physical and chemical characterization of fine particulate matter that can be used to support exposure and health effects studies.NARSTO (formerly North American Research Strategy for Tropospheric Ozone) is a public/private partnership, whose membership spans government, the utilities, industry, and academe throughout Mexico, the United States, and Canada. The primary mission is 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 available.

Ambient particulate matter organic speciation data from July - August, 2011. This dataset is associated with the following publication: Lynam, M., T. Dvonch, J. Turlington, D. Olson, and M. Landis. Combustion-Related Organic Species in Temporally Resolved Urban Airborne Particulate Matter. ATMOSPHERIC ENVIRONMENT. Elsevier Science Ltd, New York, NY, USA, 0(0): 1-33, (2017).