AMTIC - Ambient Monitoring Archive for HAPs

In October 2022, the EPA published the 2020 Ambient Monitoring Archive for the Hazardous Air Pollutants (HAPs) (i.e., "the Archive") that houses over 87 million data records from over 2,800 monitoring sites from 1990 through 2020. Over 90% of the records are from 2000 to 2020 as a result of the air toxic programs, such as the NATTS Network, the PAMS Network, the IMPROVE Network, the Community-Scale Air Toxics Ambient Monitoring grants, the Urban Air Toxics Monitoring Program, the National Atmospheric Deposition Program, and other federal, state, local, and tribal monitoring networks. Due to the size of the 2020 Archive, the Microsoft Access data files are divided by state and year; the .txt and .Rda files (generated by the R programming language) are presented by year.

Ambient Monitoring HAPs Data By Year

The 2020 Archive for HAPs data from 1990 to 2020 for each year are presented in zipped Microsoft Access databases and .txt files. Warning, these files are large.

Year	Year	Year	Year
	2020 (134 MB)	2019 (25 MB)	2018 (246 MB)
2017 (261 MB)	2016 (326 MB)	2015 ( 316 MB)	2014 (325 MB)
2013 (306 MB)	2012 (284 MB)	2011 (259 MB)	2010 (249 MB)
2009 (244 MB)	2008 (223 MB)	2007 (227 MB)	2006 (217MB)
2005 (219 MB)	2004 (156 MB)	2003 (131 MB)	2002 (117 MB)
2001 (112 MB)	2000 (93.4 MB)	1999 (83.4 MB)	1998 (76 MB)
1997 (63.9 MB)	1996 (52.6 MB)	1995 (38.1 MB)	1994 (24.9 MB)
1993 (14.2 MB)	1992 (9.7 MB)	1991 (7.7 MB)	1990 (6.3 MB)

Air Monitoring HAPs Data By State

Files are also available from 1990 to 2020 by state, the District of Columbia, Puerto Rico, and the Virgin Islands in zipped Microsoft Access databases.

State	State	State	State
Alabama (13.6 MB)	Alaska (23.7 MB)	Arizona (25.1 MB)	Arkansas (3 MB)
California (186 MB)	Colorado (34.6 MB)	Connecticut (37.5 MB)	Delaware (8.2 MB)
District of Columbia (20.5 MB)	Florida (26.8 MB)	Georgia (69.6 MB)	Hawaii (25.4 MB)
Idaho (4 MB)	Illinois (52.9 MB)	Indiana (78.7 MB)	Iowa (5.6 MB)
Kansas (6.1MB)	Kentucky (14.3 MB)	Louisiana (30.4 MB)	Maine (53.4 MB)
Maryland (43.7 MB)	Massachusetts (80.7 MB)	Michigan (48.8 MB)	Minnesota (38.7 MB)
Mississippi (13 MB)	Missouri (30.6 MB)	Montana (8.5 MB)	Nebraska (2.3 MB)
Nevada (3.9 MB)	New Hampshire (36.2 MB)	New Jersey (44.2 MB)	New Mexico (6.3 MB)
New York (79.8 MB)	North Carolina (20.6 MB)	North Dakota (3 MB)	Ohio (30.3 MB)
Oklahoma (18 MB)	Oregon (21.7 MB)	Pennsylvania (50 MB)	Puerto Rico (1.1 MB)
Rhode Island (32.6 MB)	South Carolina (19.4 MB)	South Dakota (4.3 MB)	Tennessee (5.9 MB)
Texas (1 of 2) (440 MB) Texas (2 of 2) (644 MB)	Utah (15.9 MB)	Vermont (32.1 MB)	Virgin Islands (1.1 MB)
Virginia (23.6 MB)	Washington (18.6 MB)	West Virginia (4.8 MB)	Wisconsin (91.3 MB)
Wyoming (5.8 MB)

All 2020 Archive Monitoring Data and Annual Data Summaries

All .Rda data files by year (664 MB) contains all data in the 2020 Archive presented by year in .Rda files using the R programming language.

Annual average statistics (XLSX) (173 MB) provides annual averages and other statistics by pollutant, site, sampling duration, and year and supporting information needed for trends analysis.

Supporting Files for the 2020 Archive

Field Descriptions (PDF) (1 page, 89.4 KB) describes the fields in the files for the 2020 Archive.
Data Dictionary (ZIP) (10.1 MB) contains ten data dictionaries needed for properly describing and standardizing the raw data and are recommended for providing additional context to the concentration records. AQS data dictionaries were initially retrieved from EPA's AQS website, which provided the metadata information for the AQS-submitted data. Data elements that were not in the AQS data dictionaries were subsequently added.
Supporting appendices (ZIP) (66.9 MB) contains six supporting appendices including information regarding overlapping records, invalidated records, sampling frequency code corrections, questionable values, negative concentrations, and program rankings.
Lookup Tables (XLSX) (148 KB) contain additional cross-referenced information in the annual average excel file, a high-level overview of the steps to calculate annual averages, field descriptions in the annual average excel file, the R code used to calculate the annual averages, and other descriptive information.

Supporting Documentation for the 2020 Archive

Technical Report (52 pages, 806 KB) provides background information, describes data sources, and documents the improvements, modifications, and additional data incorporated into the development of the 2020 Archive.
Annual Average Documentation (PDF) (10 pages, 638 KB) documents the steps used to calculate the annual averages along with descriptors of the corresponding R code, the quality assurance methodology and results, and answers to frequent questions.