.. index:: Introduction;
.. sectionauthor:: Clinton Mccrowey \<mccrowey \<DOT\>\ clinton \<AT\>\ epa.gov\>

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) :cite:t:`AQSDataMartWelcome` 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.
