Why your air quality app and the official API don’t match, environment minister explains in Parliament

KUALA LUMPUR, Oct 22 — The Department of Environment (DOE) in Malaysia releases the official Air Pollutant Index (API) to determine air quality and manage haze. The official API is calculated using data from 68 automatic air quality monitoring stations across the country, which monitor six major pollutants round-the-clock. These stations employ equipment and technical methods recognized by the United States Environmental Protection Agency, with stringent procedures for maintenance, calibration, and quality assurance to ensure accurate and reliable data.

Datuk Seri Arthur Joseph Kurup, Natural Resources and Environmental Sustainability Minister, addressed concerns about the accuracy, transparency, and public trust in the official API during a parliamentary session. The stations undergo daily automated zero and span checks, periodic calibration with standard gases traceable to international standards, and regular performance audits, ensuring the data's accuracy and reliability.

The official API is updated hourly, while PM2.5 and PM10 calculations are based on a 24-hour moving average. Arthur clarified that discrepancies between the official API and those displayed on platforms like the Air Quality Index (AQI) and independent applications are due to differences in scales, thresholds, categories, averaging periods, update times, and data sources.

Some platforms may rely on low-cost sensors or model-derived estimates from satellite data, which measure particle concentrations in the atmosphere rather than ground-level air quality. These satellite readings can be influenced by cloud cover and atmospheric humidity. The ministry is open to enhancing the National Haze Action Plan to ensure better coordination among agencies, especially during unhealthy or very unhealthy API levels, to safeguard public health.

Regarding haze and open burning, the government enforces a zero-tolerance policy, with the DOE issuing 3,433 enforcement actions for open-burning incidents between August and October this year.