> ## Documentation Index
> Fetch the complete documentation index at: https://mintlify.com/japsinghx/breeze-ios/llms.txt
> Use this file to discover all available pages before exploring further.

# Open-Meteo Air Quality API

> Real-time air quality data including AQI and pollutant measurements

## Overview

Breeze uses the Open-Meteo Air Quality API to provide real-time air quality information for any location worldwide. This API returns the US Air Quality Index (AQI) along with detailed measurements of specific pollutants.

## Base URL

```
https://air-quality-api.open-meteo.com/v1/air-quality
```

## Endpoints Used

### Get Current Air Quality

Fetches current air quality data for a specific location.

**Query Parameters:**

| Parameter   | Type   | Description                                   |
| ----------- | ------ | --------------------------------------------- |
| `latitude`  | Double | Geographic latitude of the location           |
| `longitude` | Double | Geographic longitude of the location          |
| `current`   | String | Comma-separated list of pollutants to include |
| `timezone`  | String | Timezone for the response (set to `"auto"`)   |

**Pollutants Requested:**

* `us_aqi` - US Air Quality Index
* `pm10` - Particulate Matter \< 10 μm
* `pm2_5` - Particulate Matter \< 2.5 μm
* `carbon_monoxide` - CO concentration
* `nitrogen_dioxide` - NO₂ concentration
* `sulphur_dioxide` - SO₂ concentration
* `ozone` - O₃ concentration

## Response Format

The API returns a JSON response with the following structure:

```json theme={null}
{
  "current": {
    "us_aqi": 42,
    "pm2_5": 12.5,
    "pm10": 18.3,
    "carbon_monoxide": 220.5,
    "nitrogen_dioxide": 15.2,
    "sulphur_dioxide": 3.8,
    "ozone": 45.6
  }
}
```

### Response Model

Breeze decodes the response into these Swift models:

```swift theme={null}
struct AirQualityResponse: Codable {
    let current: AirQuality?
}

struct AirQuality: Codable {
    let usAQI: Int
    let pm25: Double
    let pm10: Double
    let carbonMonoxide: Double
    let nitrogenDioxide: Double
    let sulphurDioxide: Double
    let ozone: Double
}
```

## Usage Example

Here's how Breeze fetches air quality data:

```swift theme={null}
func fetchAirQuality(latitude: Double, longitude: Double) async throws -> AirQuality {
    var components = URLComponents(string: baseURL)!
    components.queryItems = [
        URLQueryItem(name: "latitude", value: String(latitude)),
        URLQueryItem(name: "longitude", value: String(longitude)),
        URLQueryItem(name: "current", value: "us_aqi,pm10,pm2_5,carbon_monoxide,nitrogen_dioxide,sulphur_dioxide,ozone"),
        URLQueryItem(name: "timezone", value: "auto")
    ]
    
    guard let url = components.url else {
        throw URLError(.badURL)
    }
    
    let (data, response) = try await URLSession.shared.data(from: url)
    
    guard let httpResponse = response as? HTTPURLResponse,
          httpResponse.statusCode == 200 else {
        throw URLError(.badServerResponse)
    }
    
    let decoder = JSONDecoder()
    let result = try decoder.decode(AirQualityResponse.self, from: data)
    
    guard let airQuality = result.current else {
        throw NSError(domain: "AirQualityService", code: 1, 
                     userInfo: [NSLocalizedDescriptionKey: "No air quality data available"])
    }
    
    return airQuality
}
```

See AirQualityService.swift:10

## Multiple Location Queries

The API supports querying multiple locations simultaneously by passing comma-separated coordinates:

```swift theme={null}
func fetchMultipleCities(_ cities: [TopCity]) async -> [(city: TopCity, aqi: Int?)] {
    let lats = cities.map { String($0.lat) }.joined(separator: ",")
    let lons = cities.map { String($0.lon) }.joined(separator: ",")
    
    var components = URLComponents(string: baseURL)!
    components.queryItems = [
        URLQueryItem(name: "latitude", value: lats),
        URLQueryItem(name: "longitude", value: lons),
        URLQueryItem(name: "current", value: "us_aqi")
    ]
    
    // ... fetch and parse response
}
```

See AirQualityService.swift:42

## AQI Levels

Breeze interprets AQI values according to US EPA standards:

| AQI Range | Level                          | Description                                     |
| --------- | ------------------------------ | ----------------------------------------------- |
| 0-25      | Excellent                      | Pristine air quality                            |
| 26-50     | Good                           | No health concerns                              |
| 51-75     | Moderate                       | Acceptable for most people                      |
| 76-100    | Slightly High                  | May affect sensitive groups                     |
| 101-150   | Unhealthy for Sensitive Groups | Children, elderly should limit outdoor exposure |
| 151-200   | Unhealthy                      | Everyone may experience effects                 |
| 201-300   | Very Unhealthy                 | Serious health concerns                         |
| 300+      | Hazardous                      | Emergency conditions                            |

## Rate Limits

Open-Meteo APIs are free and do not require an API key. They have generous rate limits suitable for most applications.

## Reference

* [Open-Meteo Air Quality API Documentation](https://open-meteo.com/en/docs/air-quality-api)
* Service Implementation: `BreezeApp/Services/AirQualityService.swift`
* Data Models: `BreezeApp/Models/AirQuality.swift`