本文件有助于理解ISO 19154中定义的通用公共访问（UPA）上下文信息模型，以建立UPA到地理信息（GI）环境。此外，本文件说明了UPA上下文信息模型是如何设计和实现的，以从基于地理信息系统（GIS）的空气质量信息系统提供空气质量信息服务。用于空气质量信息的UPA上下文信息模型只是实现UPA到GI的所有可能示例中的一个示例，可以满足ISO 19154的要求。

This document facilitates an understanding of the Ubiquitous Public Access (UPA) context information model, as defined in ISO 19154, to establish a UPA-to-Geographic Information (GI) environment. In addition, this document illustrates how the UPA context information model is designed and implemented to provide an air quality information service from a geographic information system (GIS)-based air quality information system. The UPA context information model for air quality information is only a sample of all possible examples to realize the UPA-to-GI that could satisfy the requirements of ISO 19154.