Open-Meteo Air Quality API

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

{
  "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
  }
}

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
}

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
}

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
}