DOI: 10.7910/dvn/3h7dnp
title: Annual PM2.5 Component Concentrations for the Contiguous United States, 50-m Urban Grid and 1-km Non-Urban Grid (2000-2019)

description: &lt;p&gt;&lt;i&gt;This dataset contains many files&lt;/i&gt;; use the Tree view below or &lt;a href=https://dataverse.harvard.edu/api/datasets/:persistentId/dirindex?persistentId=doi:10.7910/DVN/3H7DNP&gt;Dataverse API directory index&lt;/a&gt; to get a condensed overview of what is available. See the &lt;code&gt;README-PM-components.pdf&lt;/code&gt; file for more information.&lt;/p&gt;

&lt;h3&gt;Overview&lt;/h3&gt;

&lt;p&gt;This dataset includes annual predictions of PM&lt;sub&gt;2.5&lt;/sub&gt; components across the contiguous U.S from 2000 to 2019. Predictions are made on a 50-m grid within urban areas, as defined by the &lt;a href="https://www.census.gov/cgi-bin/geo/shapefiles/index.php?year=2010&layergroup=Urban+Areas"&gt;U.S. Census Bureau 2010 TIGER/Line Shapefiles&lt;/a&gt;, and on a 1-km outside of those areas.&lt;/p&gt;

&lt;p&gt;These predictions were produced by a set of super-learning ensemble models in which the predictions from a variety of machine learners were then used to train a second stage of machine learners. For each component-urbanicity combination, the second-stage machine learner with the highest R&lt;sup&gt;2&lt;/sup&gt; was chosen as the final model. Overall cross-validated R&lt;sup&gt;2&lt;/sup&gt; values ranged from 0.856-0.952 for the major components (EC, NH&lt;sub&gt;4&lt;/sub&gt;&lt;sup&gt;+&lt;/sup&gt;, NO&lt;sub&gt;3&lt;/sub&gt;&lt;sup&gt;-&lt;/sup&gt;, OC, and SO&lt;sub&gt;4&lt;/sub&gt;&lt;sup&gt;2-&lt;/sup&gt;) in urban areas and 0.878-0.957 outside urban areas, and 0.797-0.878 for the trace elements (Br, Ca, Cu, Fe, K, Ni, Pb, Si, V, and Zn) in urban areas and 0.787-0.881 outside urban areas. Please refer to the README file for the exact values for each element and location.&lt;/p&gt;

&lt;p&gt;Predictions are available in RDS and plaintext formats, and the prediction grid is available as CSV and GeoPackage files. Example R code is provided to facilitate reading and common merge operations.&lt;/p&gt;

&lt;p&gt;When using this dataset, please also cite the Related Publications in the Metadata tab below (also available in the README file), which further detail the data sources and processes used to produce these predictions.&lt;/p&gt;

&lt;p&gt;This is a reupload and format change of data that was previously available on SEDAC / EarthData under the names &lt;a href=https://web.archive.org/web/20241003161749/https://sedac.ciesin.columbia.edu/data/set/aqdh-pm2-5-component-ec-nh4-no3-oc-so4-50m-1km-contiguous-us-2000-2019&gt;"Annual Mean PM2.5 Components (EC, NH4, NO3, OC, SO4) 50m Urban and 1km Non-Urban Area Grids for Contiguous U.S., v1 (2000 – 2019)"&lt;/a&gt; and &lt;a href=https://web.archive.org/web/20241009160125/https://sedac.ciesin.columbia.edu/data/set/aqdh-pm2-5-component-trace-elements-50m-1km-contiguous-us-2000-2019&gt;"Annual Mean PM2.5 Components Trace Elements (TEs) 50m Urban and 1km Non-Urban Area Grids for Contiguous U.S., v1 (2000 – 2019)"&lt;/a&gt;.&lt;/p&gt;

&lt;h3&gt;Bulk downloads&lt;/h3&gt;

&lt;p&gt;&lt;code&gt;wget&lt;/code&gt; and other download programs can be used to bulk download files using the Dataverse API directory index:&lt;/p&gt;

&lt;p&gt;&lt;code&gt;wget --recursive --execute robots=off --no-host-directories --span-hosts --content-disposition 'https://dataverse.harvard.edu/api/datasets/:persistentId/dirindex?persistentId=doi:10.7910/DVN/3H7DNP'&lt;/code&gt;&lt;/p&gt;
description: Air Quality Data for Health-Related Applications