M
API Matrix

OpenAQ API

⭐ Beginner's Pick Environment / API Key Intermediate HTTPS
Varies by plan (check documentation)
72 Score
Grade B
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Overview

OpenAQ is an open-source platform providing access to air quality data aggregated from thousands of government and research-grade monitoring stations worldwide. It requires a free API key for higher usage, but unauthenticated requests are also allowed at low rate limits. Developers can query historical and real-time PM2.5, NO2, ozone, and other pollutant measurements by location or country.

💡

Beginner Tip

Register for a free API key at openaq.org to increase your rate limit from 60 to 1,000 requests per hour. Start by exploring /locations to find monitoring stations near you, then use the location ID in /measurements to fetch actual pollutant readings.

Available Data

Use case: Integrate open air quality data data into web and mobile applications
OpenAQ data via REST API
JSON-formatted response data
Requires API key authentication

Example Response

JSON Response 
{
  "status": "success",
  "data": {
    "result": "Data from OpenAQ",
    "description": "Open air quality data",
    "timestamp": "2025-01-15T10:00:00Z"
  }
}

Field Reference

results Array of location or measurement objects matching the query
results[].id Unique identifier for the monitoring location, used to query measurements at that station
results[].name Name or identifier of the monitoring station
results[].country Country information including ISO code and full name where the station is located
results[].coordinates Latitude and longitude of the monitoring station
meta.total Total number of records matching the query before pagination

Implementation Example 

const url = "https://docs.openaq.org/";
// Replace headers or query params with the values required by this API.
const response = await fetch(url, {
  headers: {
  "X-API-Key": "YOUR_API_KEY"
  }
});
if (!response.ok) throw new Error(`Request failed: ${response.status}`);
const data = await response.json();
console.log(data);

What Can You Build?

Note: These code examples are AI-generated and unverified. Always refer to the official API documentation for accurate usage.

Common Errors & Troubleshooting

429 Too Many Requests Exceeded the unauthenticated rate limit of 60 requests per hour
✓ Register at openaq.org for a free API key and include it as an X-API-Key header to get a higher rate limit
Empty results array The filters applied return no matching locations or measurements
✓ Try broader filters — remove date ranges first, check valid country codes, or use a different parameter (radius instead of city name)
422 Validation Error Invalid parameter values such as a malformed date string or unsupported parameter name
✓ Use ISO 8601 date format (e.g. 2024-01-01T00:00:00Z) and refer to the OpenAQ v3 API docs for valid parameter names and formats

Matrix Score Breakdown

🌐 Reachability 30/30
⚡ Speed 5/20
🔒 Security 15/15
🛠 Developer XP 12/20
✓ Reliability 10/15

Partially tested on Apr 5, 2026

Technical Specifications

Auth API Key
HTTPS REQUIRED
CORS UNKNOWN
Category Environment
Difficulty Intermediate
Verified: 2026-04-04

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