Air Quality Index

Real-time air quality monitoring with US AQI standards and health recommendations

Overview

The Air Quality Index (AQI) card is the centerpiece of the Breeze dashboard, displaying the current air quality using the US EPA Air Quality Index standard. It features an animated circular progress indicator, color-coded status levels, and personalized health recommendations.

Implementation

AQICard Component

The AQI card is implemented in AQICard.swift as a SwiftUI view that observes the dashboard’s view model:

AQICard.swift

struct AQICard: View {
    @ObservedObject var viewModel: DashboardViewModel
    
    var body: some View {
        VStack(spacing: 16) {
            // AQI Circle
            ZStack {
                // Background circle
                Circle()
                    .stroke(viewModel.aqiColor.opacity(0.2), lineWidth: 12)
                    .frame(width: 160, height: 160)
                
                // Progress circle
                Circle()
                    .trim(from: 0, to: progressValue)
                    .stroke(
                        viewModel.aqiColor,
                        style: StrokeStyle(lineWidth: 12, lineCap: .round)
                    )
                    .frame(width: 160, height: 160)
                    .rotationEffect(.degrees(-90))
                    .animation(.easeInOut(duration: 1.0), value: progressValue)
                
                // AQI Value
                VStack(spacing: 4) {
                    Text("\(viewModel.airQuality?.usAQI ?? 0)")
                        .font(.system(size: 56, weight: .bold, design: .rounded))
                        .foregroundColor(viewModel.aqiColor)
                    
                    Text("US AQI")
                        .font(.caption)
                        .foregroundColor(.secondary)
                }
            }
        }
    }
    
    private var progressValue: CGFloat {
        guard let aqi = viewModel.airQuality?.usAQI else { return 0 }
        // Scale AQI 0-500 to 0-1
        return min(CGFloat(aqi) / 500.0, 1.0)
    }
}

Visual Design

The card features:

1. Circular Progress Indicator

   • Animated progress ring showing AQI value
   • Color changes based on air quality level
   • Scales from 0-500 (US AQI range)

2. Large AQI Number

   • Bold, rounded font for easy reading
   • Color-coded to match air quality status
   • “US AQI” label below

3. Status Badge

   • Text description (Good, Moderate, Unhealthy, etc.)
   • Colored circle indicator
   • Detailed health impact description

4. Health Tips

   • Contextual recommendations based on AQI level
   • Bulleted list format
   • Integrated seamlessly into the card

AQI Status Levels

The app uses the standard US EPA AQI categories, defined in AirQuality.swift:

AirQuality.swift

struct AQIStatus {
    let text: String
    let emoji: String
    let description: String
    let color: String
    let tips: [String]
    
    static func from(aqi: Int) -> AQIStatus {
        switch aqi {
        case 0...25:
            return AQIStatus(
                text: "Excellent",
                emoji: "✨",
                description: "Air quality is pristine! Perfect day for adventures.",
                color: "aqiGood",
                tips: [
                    "Air is exceptionally clean right now",
                    "No air quality concerns at this level"
                ]
            )
        case 26...50:
            return AQIStatus(
                text: "Good",
                emoji: "😊",
                description: "Air quality is great. Breathe easy!",
                color: "aqiGood",
                tips: [
                    "Air quality meets health standards",
                    "Pollutant levels are low",
                    "No health risks from air quality"
                ]
            )
        case 51...100:
            return AQIStatus(
                text: "Moderate",
                emoji: "😐",
                description: "Air quality is acceptable for most people.",
                color: "aqiModerate",
                tips: [...]
            )
        // ... additional levels
        }
    }
}

Complete AQI Scale

Excellent (0-25)

• Color: Green (#34c759)
• Description: Air quality is pristine! Perfect day for adventures.
• Health Impact: Air is exceptionally clean, no concerns

Good (26-50)

• Color: Green (#34c759)
• Description: Air quality is great. Breathe easy!
• Health Impact: Air quality meets health standards, pollutant levels are low

Moderate (51-100)

• Color: Orange (#ff9500)
• Description: Air quality is acceptable for most people.
• Health Impact: Unusually sensitive people may experience minor effects

Unhealthy for Sensitive Groups (101-150)

• Color: Orange-Red (#ff6b00)
• Description: Sensitive groups should be cautious.
• Health Impact: May affect children, elderly, and those with respiratory conditions

Unhealthy (151-200)

• Color: Red (#ff3b30)
• Description: Everyone may feel the effects now.
• Health Impact: Air quality is unhealthy for everyone

Very Unhealthy (201-300)

• Color: Purple (#af52de)
• Description: Serious health concerns for everyone.
• Health Impact: Air pollutants are at dangerous levels

Hazardous (301+)

• Color: Maroon (#8e0000)
• Description: Emergency conditions. Seriously bad air.
• Health Impact: Air quality has reached hazardous levels

Color System

Colors are defined in Color+Theme.swift using hex values:

Color+Theme.swift

extension Color {
    // AQI Colors
    static let aqiGood = Color(hex: "34c759")
    static let aqiModerate = Color(hex: "ff9500")
    static let aqiUnhealthySensitive = Color(hex: "ff6b00")
    static let aqiUnhealthy = Color(hex: "ff3b30")
    static let aqiVeryUnhealthy = Color(hex: "af52de")
    static let aqiHazardous = Color(hex: "8e0000")
}

Health Recommendations

Each AQI level includes tailored health tips displayed in the card:

// Health Tips Section
VStack(alignment: .leading, spacing: 12) {
    HStack(spacing: 8) {
        Image(systemName: "heart.fill")
            .font(.system(size: 12, weight: .semibold))
            .foregroundColor(.pink)
        
        Text("What You Can Do")
            .font(.subheadline)
            .fontWeight(.semibold)
    }
    
    VStack(spacing: 10) {
        ForEach(Array(status.tips.enumerated()), id: \.offset) { index, tip in
            HStack(alignment: .top, spacing: 10) {
                Circle()
                    .fill(viewModel.aqiColor.opacity(0.8))
                    .frame(width: 6, height: 6)
                    .padding(.top, 6)
                
                Text(tip)
                    .font(.caption)
                    .foregroundColor(.secondary)
            }
        }
    }
}

Sharing Functionality

The AQI card includes a share button using SwiftUI’s ShareLink:

ShareLink(
    item: "Air Quality in \(viewModel.locationName): AQI \(viewModel.airQuality?.usAQI ?? 0) - \(viewModel.aqiStatus?.text ?? "Unknown")",
    subject: Text("Air Quality Report"),
    message: Text("Check out the air quality via Breeze!")
) {
    Label("Share", systemImage: "square.and.arrow.up")
        .font(.subheadline)
        .fontWeight(.medium)
}
.buttonStyle(.bordered)
.tint(viewModel.aqiColor)

Data Source

Air quality data is fetched from the Open-Meteo Air Quality API via AirQualityService.swift:10-39:

AirQualityService.swift

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")
    ]
    // ... fetch and decode
}

File Locations

• Component: BreezeApp/Views/Dashboard/AQICard.swift
• Model: BreezeApp/Models/AirQuality.swift
• Service: BreezeApp/Services/AirQualityService.swift
• Colors: BreezeApp/Extensions/Color+Theme.swift