AMTIC - Ambient Monitoring Archive for HAPs

In October 2023, the EPA published the 2021 Ambient Monitoring Archive (AMA) for the  Hazardous Air Pollutants (HAPs) (i.e., "the Archive") that houses over 101 million data records from over 5,000 monitoring sites from 1990 through 2021. Data come from EPA's Air Quality System, the Texas Commission on Environmental Quality, the South Coast Air Quality Management District, the National Atmospheric Deposition Program, the National Oceanic and Atmospheric Administration, the Massachusetts Institute of Technology, the Louisiana Department of Environmental Quality, other state, local, tribal, and federal monitoring agencies, and other academic, community, and short-term studies. Due to the size of the 2021 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 2021 Archive for HAPs data from 1990 to 2021 are presented by year in zipped Microsoft Access databases and .txt files. Please note that file sizes range from 6.53 MB to 465 MB.

Year	Year	Year	Year
2021           (465 MB)	2020         (228 MB)	2019       (228 MB)	2018         (215 MB)
2017         (229 MB)	2016         (286 MB)	2015        ( 277 MB)	2014         (287 MB)
2013         (264 MB)	2012         (245 MB)	2011         (224 MB)	2010          (212 MB)
2009         (205 MB)	2008         (187 MB)	2007         (193 MB)	2006         (183MB)
2005         (182 MB)	2004                 (159 MB)	2003                (136 MB)	2002         (118 MB)
2001         (114 MB)	2000                 (94.7 MB)	1999         (84.1 MB)	1998                (77.1 MB)
1997         (63.8 MB)	1996         (60.3 MB)	1995         (43.4 MB)	1994         (24.2 MB)
1993         (13.6 MB)	1992         (9.71MB)	1991         (7.98 MB)	1990         (6.53 MB)

Air Monitoring HAPs Data By State

Files are also available from 1990 to 2021 by state, the District of Columbia, Puerto Rico, and the Virgin Islands in zipped Microsoft Access databases. Please note that file sizes range from 852 KB to 615 MB.

State	State	State	State
Alabama (9.85 MB)	Alaska  (21.9 MB)	Arizona (18.2 MB)	Arkansas  (2.24 MB)
California (345 MB)	Colorado  (36.3 MB)	Connecticut  (33.3 MB)	Delaware  (7.39MB)
District of Columbia  (19.4 MB)	Florida (24.0 MB)	Georgia (53.5 MB)	Hawaii (23.1 MB)
Idaho (3.5 MB)	Illinois (39.1 MB)	Indiana (70.8 MB)	Iowa (5.11 MB)
Kansas (5.19MB)	Kentucky (13.5 MB)	Louisiana (34.9 MB)	Maine (46.6 MB)
Maryland (39.8 MB)	Massachusetts (53.4 MB)	Michigan (45 MB)	Minnesota (35.9 MB)
Mississippi  (9.54 MB)	Missouri (27.7 MB)	Montana (7.47 MB)	Nebraska (2.04 MB)
Nevada (3.75 MB)	New Hampshire (26.7 MB)	New Jersey (42 MB)	New Mexico (7.55 MB)
New York (63 MB)	North Carolina (15.8 MB)	North Dakota (3.0 MB)	Ohio (19.8 MB)
Oklahoma (13.1 MB)	Oregon (20.0 MB)	Pennsylvania  (46.1 MB)	Puerto Rico (1.01 MB)
Rhode Island (23.3 MB)	South Carolina (14.0 MB)	South Dakota (3.88 MB)	Tennessee (5.20 MB)
Texas (1 of 2) (572 MB) Texas (2 of 2)  (615 MB)	Utah (13.7 MB)	Vermont (19.7 MB)	Virgin Islands (852 KB)
Virginia (17.5 MB)	Washington (17.2 MB)	West Virginia  (4.26 MB)	Wisconsin (89.1 MB)
Wyoming (4.78 MB)

All 2021 Archive Monitoring Data and Annual Data Summaries

All .Rda data files by year (738 MB) contains all data in the 2021 Archive presented by year in .Rda files (generated by the R programming language).

Annual Statistics (XLSX) (185 MB) provides annual statistics by pollutant, site, sampling duration, and year and supporting information assisting in trends analysis.

Supporting Files for the 2021 Archive

• Field Descriptions (PDF) (1 page, 68.3 KB) describes the fields in the 2021 Archive files.

• Data Dictionary (ZIP) (11.9 MB) contains ten data dictionaries needed for describing and standardizing the raw data and are recommended for providing additional context to the concentration records. Data dictionaries are initially retrieved from EPA's AQS website with additional data elements added.
• Supporting appendices (ZIP) (86.4 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) (241 KB) contains additional cross-referenced information in the annual statistics excel file, field descriptions in the annual statistics excel file, R code used to calculate the annual statistics, and other descriptive information. 

Supporting Documentation for the 2021 Archive

• Technical Report (54 pages, 1.01 MB)  provides background information, describes data sources, and documents the improvements, modifications, and additional data incorporated into the development of the 2021 Archive.
• Annual Statistics Documentation (PDF) (10 pages, 437 KB) documents the steps used to calculate the annual statistics along with descriptors of the corresponding R code, the quality assurance methodology and results, and answers to frequent questions.