Exploring the Ozon3 Perl Module for Air Quality Data

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https://sbmesh.com/Ozon3.pm

The Ozon3 Perl module is a lightweight interface to the World Air Quality Index (WAQI) API, designed to fetch real-time air quality data based on geographic coordinates. Modeled after the Python Ozon3 library, it provides a robust way to retrieve Air Quality Index (AQI) and pollutant metrics with optional rate limiting.

Key Features

  • WAQI API Integration: Connects to https://api.waqi.info/ to retrieve air quality data.
  • Rate Limiting: Supports up to 1000 API calls per second using Schedule::RateLimiter (optional).
  • Error Handling: Comprehensive checks for invalid tokens, rate limits, and API errors.
  • Data Extraction: Returns detailed AQI, pollutant levels (e.g., PM2.5, PM10, NO2), and health implications.

Core Components

Initialization (new)

  • Requires a WAQI API token.
  • Sets up LWP::UserAgent for HTTP requests and Schedule::RateLimiter for throttling.
  • Validates the token by querying the API with a test request for London.

Fetching Data (get_air_quality)

  • Takes latitude and longitude as inputs.
  • Constructs a URL with escaped parameters and the API token.
  • Returns a hashref containing AQI, pollutant concentrations, station details, and health implications.

Data Processing (_extract_live_data)

  • Extracts metrics like AQI, PM2.5, PM10, CO, and meteorological data (e.g., temperature, humidity).
  • Normalizes pollutant names (e.g., pm25 to pm2.5).
  • Converts AQI into human-readable meanings and health implications.

Utility Methods

  • _check_token_validity: Verifies the API token.
  • _check_and_get_data_obj: Handles HTTP responses and API errors.
  • _aqi_meaning: Maps AQI values to categories (e.g., “Good,” “Unhealthy”) and health risks.
  • _as_float: Ensures numeric values are properly formatted.

Usage Example

use Ozon3;
my $ozon3 = Ozon3->new(token => 'your_waqi_token');
my $aq = $ozon3->get_air_quality(37.7749, -122.4194); # San Francisco
if ($aq) {
    print "AQI: $aq->{aqi} ($aq->{aqi_meaning})\n";
    print "PM2.5: $aq->{pm2.5} µg/m³\n";
}

Dependencies

  • LWP::UserAgent: For HTTP requests.
  • JSON::MaybeXS: For parsing API responses.
  • URI::Escape: For URL encoding.
  • Schedule::RateLimiter: Optional, for rate limiting.

Notes

  • The module gracefully handles missing dependencies or failed initializations.
  • Rate limiting is optional; if Schedule::RateLimiter fails, the module proceeds without it.
  • Comprehensive error messages aid debugging (e.g., invalid tokens, unknown stations).

Conclusion

The Ozon3 module is a reliable tool for developers needing air quality data in Perl applications. Its robust error handling and flexible design make it suitable for both small scripts and large systems.

Source: Adapted from the Ozon3 Python library by Ozon3Org.

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