3. Introduction

The pyaqsapi package for the python 3 programming environment allows a python 3 programming environment to connect to and retrieve data from the United States Environmental Protection Agency’s (US EPA) Air Quality System (AQS) Data Mart API v2 (Air Quality System) interface directly. This package enables the data user to omit legacy challenges including coercing data from a JSON object to a usable python 3 object, retrieving multiple years of data, formatting API requests, retrieving results, handling credentials, requesting multiple pollutant data and rate limiting data requests. All the basic functionality of the API have been implemented that are available from the AQS API Data Mart server. The library connects to AQS Data Mart API via Hypertext Transfer Protocol (HTTP) so there is no need to install external ODBC drivers, configure ODBC connections or deal with the security vulnerabilities associated with them. Most functions have a parameter, return_header which by default is set to FALSE. If the user decides to set return_header to TRUE, then that function will return a python 3 AQSAPI_V2 object. An AQSAPI_V2 object has instance methods for retrieving the data requested, header information, and other metadata related to the API call. After each call to the API a five second stall is invoked to help prevent overloading the Data Mart API server and to serve as a simple rate limit.

3.1. The air Quality System (AQS)

The Clean Air act requires all federal, state, local and tribal air pollution control agencies monitor ambient air for concentrations of certain air pollutants. Codified in 40 CFR Part 58 are the statutory requirements for these monitoring programs, including monitoring network technical requirements, operating schedules, data certification, data submittal and archiving requirements. In addition to the required air pollution and meteorological monitoring, pollution control agencies often perform additional and/or voluntary air monitoring.

• The three objectives of ambient air monitoring programs as stated in 40 CFR

  Part 58 Appendix D.1 are as follows:

  • Provide air pollution data to the public in a timely manner;

  • Support compliance with ambient air quality standards and emissions

    strategy development; and

  • Support for air pollution research studies.

As required by 40 CFR Part 58, air pollution and meteorological data is submitted to the United States Environmental Protection Agency along with associated metadata and quality assurance metadata via EPA’s Air Quality System (AQS):cite:t:@AboutAQSdata.

3.2. About AQS Data Mart

AQS Data Mart is a publicly accessible mirror of data stored on the AQS database designed to make air monitoring data more accessible and useful to the technical community, scientific community and the general public. Data on AQS is copied to AQS Data Mart once per week and this data is made available to the public through web-based applications and APIs (application programming interface) . pyaqsapi functions use the APIs provided by AQS Data Mart to retrieve data.