World Air Quality Index (WAQI) Feed API

openapi: 3.1.0
info:
  title: World Air Quality Index (WAQI) JSON Feed API
  description: The WAQI JSON API provides real-time air quality data, AQI readings, pollutant measurements, and station data for more than 12,000 monitoring stations worldwide. It delivers city-level and station-level air quality index values for pollutants including PM2.5, PM10, NO2, CO, SO2, and Ozone, along with geo-location queries, weather conditions, and 3-8 day forecast data. Authentication requires a free token obtained from the Air Quality Open Data Platform.
  version: 1.0.0
  contact:
    name: WAQI Support
    url: https://aqicn.org/api/
  license:
    name: Non-Commercial Use
    url: https://aqicn.org/api/
  termsOfService: https://aqicn.org/api/
servers:
- url: https://api.waqi.info
  description: WAQI Production API
security:
- tokenAuth: []
tags:
- name: Feed
  description: Air quality feed endpoints for city, geo, and IP-based queries
paths:
  /feed/{city}/:
    get:
      operationId: getCityFeed
      summary: Get air quality feed for a city
      description: Returns the current air quality data for a specified city or monitoring station. Provides AQI readings, pollutant measurements (PM2.5, PM10, NO2, CO, SO2, Ozone), station coordinates, weather conditions, and forecast data.
      tags:
      - Feed
      parameters:
      - name: city
        in: path
        required: true
        description: City name or station identifier (e.g., 'shanghai', 'beijing', '@8397' for station ID). Use 'here' for IP-based geolocation.
        schema:
          type: string
          examples:
          - shanghai
          - beijing
          - '@8397'
      - name: token
        in: query
        required: true
        description: API authentication token obtained from the Air Quality Open Data Platform.
        schema:
          type: string
          example: demo
      responses:
        '200':
          description: Successful response with air quality feed data
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/FeedResponse'
              example:
                status: ok
                data:
                  aqi: 68
                  idx: 1437
                  attributions:
                  - url: http://www.semc.gov.cn/aqi/
                    name: Shanghai Environmental Monitoring Center
                  city:
                    geo:
                    - 31.2047372
                    - 121.4489017
                    name: Shanghai
                    url: https://aqicn.org/city/shanghai
                  dominentpol: pm25
                  iaqi:
                    co:
                      v: 4
                    no2:
                      v: 11.3
                    o3:
                      v: 38.3
                    pm10:
                      v: 56
                    pm25:
                      v: 68
                    so2:
                      v: 2.3
                  time:
                    s: '2024-01-15 12:00:00'
                    tz: +08:00
                    v: 1705320000
                    iso: '2024-01-15T12:00:00+08:00'
                  forecast:
                    daily:
                      o3:
                      - avg: 21
                        day: '2024-01-15'
                        max: 29
                        min: 17
                      pm10:
                      - avg: 38
                        day: '2024-01-15'
                        max: 47
                        min: 30
                      pm25:
                      - avg: 68
                        day: '2024-01-15'
                        max: 82
                        min: 59
                      uvi:
                      - avg: 1
                        day: '2024-01-15'
                        max: 3
                        min: 0
                  debug:
                    sync: '2024-01-15T12:05:00+09:00'
        '400':
          description: Invalid request or unknown city/station
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorResponse'
              example:
                status: error
                data: Unknown city or station
        '401':
          description: Invalid or missing API token
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorResponse'
              example:
                status: error
                data: Invalid key
  /feed/geo:{lat};{lng}/:
    get:
      operationId: getGeoFeed
      summary: Get air quality feed by geographic coordinates
      description: Returns the air quality data for the nearest monitoring station to the specified latitude and longitude coordinates.
      tags:
      - Feed
      parameters:
      - name: lat
        in: path
        required: true
        description: Latitude of the target location.
        schema:
          type: number
          format: float
          example: 37.7749
      - name: lng
        in: path
        required: true
        description: Longitude of the target location.
        schema:
          type: number
          format: float
          example: -122.4194
      - name: token
        in: query
        required: true
        description: API authentication token.
        schema:
          type: string
          example: demo
      responses:
        '200':
          description: Successful response with air quality feed data for the nearest station
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/FeedResponse'
        '400':
          description: Invalid coordinates
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorResponse'
        '401':
          description: Invalid or missing API token
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorResponse'
  /feed/here/:
    get:
      operationId: getIPFeed
      summary: Get air quality feed based on requester IP address
      description: Returns the air quality data for the nearest monitoring station to the geographic location inferred from the requesting IP address.
      tags:
      - Feed
      parameters:
      - name: token
        in: query
        required: true
        description: API authentication token.
        schema:
          type: string
          example: demo
      responses:
        '200':
          description: Successful response with air quality feed data based on IP geolocation
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/FeedResponse'
        '401':
          description: Invalid or missing API token
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorResponse'
components:
  schemas:
    ForecastDay:
      type: object
      description: Daily forecast values for a single pollutant
      properties:
        avg:
          type: number
          description: Average AQI value for the day
        day:
          type: string
          format: date
          description: Forecast date (YYYY-MM-DD)
          example: '2024-01-15'
        max:
          type: number
          description: Maximum AQI value for the day
        min:
          type: number
          description: Minimum AQI value for the day
      required:
      - avg
      - day
      - max
      - min
    PollutantValue:
      type: object
      description: A single pollutant or measurement value
      properties:
        v:
          type: number
          format: float
          description: The measurement value
      required:
      - v
    Attribution:
      type: object
      description: Data attribution source
      properties:
        url:
          type: string
          format: uri
          description: URL of the attribution source
        name:
          type: string
          description: Name of the attribution source
        logo:
          type: string
          description: Logo filename for the attribution source
      required:
      - url
      - name
    ErrorResponse:
      type: object
      description: Error response returned when a request fails
      properties:
        status:
          type: string
          enum:
          - error
          description: Always 'error' for error responses
        data:
          type: string
          description: Human-readable error message
          example: Unknown city or station
      required:
      - status
      - data
    TimeInfo:
      type: object
      description: Timestamp information for the data reading
      properties:
        s:
          type: string
          description: Timestamp in local station time (YYYY-MM-DD HH:MM:SS)
          example: '2024-01-15 12:00:00'
        tz:
          type: string
          description: Timezone offset of the station (e.g., +08:00)
          example: +08:00
        v:
          type: integer
          description: Unix epoch timestamp
          example: 1705320000
        iso:
          type: string
          format: date-time
          description: ISO 8601 formatted timestamp with timezone
          example: '2024-01-15T12:00:00+08:00'
      required:
      - s
      - tz
      - v
    Forecast:
      type: object
      description: Air quality forecast data (3-8 days)
      properties:
        daily:
          type: object
          description: Daily forecast values by pollutant
          properties:
            o3:
              type: array
              items:
                $ref: '#/components/schemas/ForecastDay'
            pm10:
              type: array
              items:
                $ref: '#/components/schemas/ForecastDay'
            pm25:
              type: array
              items:
                $ref: '#/components/schemas/ForecastDay'
            uvi:
              type: array
              items:
                $ref: '#/components/schemas/ForecastDay'
              description: UV Index forecast
    CityInfo:
      type: object
      description: City or station location information
      properties:
        geo:
          type: array
          description: Geographic coordinates [latitude, longitude]
          items:
            type: number
            format: float
          minItems: 2
          maxItems: 2
          example:
          - 31.2047372
          - 121.4489017
        name:
          type: string
          description: Display name of the city or station
          example: Shanghai
        url:
          type: string
          format: uri
          description: URL to the city or station page on aqicn.org
          example: https://aqicn.org/city/shanghai
      required:
      - geo
      - name
      - url
    IndividualAQI:
      type: object
      description: Individual pollutant AQI sub-index values
      properties:
        co:
          $ref: '#/components/schemas/PollutantValue'
          description: Carbon Monoxide (CO) AQI sub-index
        no2:
          $ref: '#/components/schemas/PollutantValue'
          description: Nitrogen Dioxide (NO2) AQI sub-index
        o3:
          $ref: '#/components/schemas/PollutantValue'
          description: Ozone (O3) AQI sub-index
        pm10:
          $ref: '#/components/schemas/PollutantValue'
          description: Particulate Matter 10 micrometers (PM10) AQI sub-index
        pm25:
          $ref: '#/components/schemas/PollutantValue'
          description: Particulate Matter 2.5 micrometers (PM2.5) AQI sub-index
        so2:
          $ref: '#/components/schemas/PollutantValue'
          description: Sulfur Dioxide (SO2) AQI sub-index
        t:
          $ref: '#/components/schemas/PollutantValue'
          description: Temperature
        w:
          $ref: '#/components/schemas/PollutantValue'
          description: Wind speed
        h:
          $ref: '#/components/schemas/PollutantValue'
          description: Humidity
        p:
          $ref: '#/components/schemas/PollutantValue'
          description: Atmospheric pressure
        wg:
          $ref: '#/components/schemas/PollutantValue'
          description: Wind gust
    FeedData:
      type: object
      description: Air quality feed data for a monitoring station
      properties:
        aqi:
          type: integer
          description: The overall Air Quality Index value
          example: 68
        idx:
          type: integer
          description: Unique station identifier in the WAQI network
          example: 1437
        attributions:
          type: array
          description: List of data attribution sources
          items:
            $ref: '#/components/schemas/Attribution'
        city:
          $ref: '#/components/schemas/CityInfo'
        dominentpol:
          type: string
          description: The dominant pollutant driving the AQI value
          enum:
          - pm25
          - pm10
          - no2
          - co
          - so2
          - o3
          example: pm25
        iaqi:
          $ref: '#/components/schemas/IndividualAQI'
        time:
          $ref: '#/components/schemas/TimeInfo'
        forecast:
          $ref: '#/components/schemas/Forecast'
        debug:
          type: object
          description: Debug information
          properties:
            sync:
              type: string
              format: date-time
              description: Timestamp of the last data synchronization
      required:
      - aqi
      - idx
      - city
      - iaqi
      - time
    FeedResponse:
      type: object
      properties:
        status:
          type: string
          enum:
          - ok
          - error
          description: Response status indicator
        data:
          $ref: '#/components/schemas/FeedData'
      required:
      - status
      - data
  securitySchemes:
    tokenAuth:
      type: apiKey
      in: query
      name: token
      description: API token obtained from the Air Quality Open Data Platform at https://aqicn.org/data-platform/token/
externalDocs:
  description: WAQI JSON API Documentation
  url: https://aqicn.org/json-api/doc/