The Environment Ministry’s current plan on air quality control lacks in accuracy and efficacy by overlooking a number of important factors and exaggerating numbers, the nation’s audit agency said Tuesday.

According to the Board of Audit and Inspection, the ministry failed to identify main pollutants causing air pollution and erroneously measured the amount of fine dust in the air. It also overestimated the amount of fine dust reduced through the plan.

The assessment came as the audit agency released a review report on the ministry’s second batch of the air quality management plan over the period of 2015 to 2024 amid growing public calls for accurate dust observation system.

The report pointed out that the ministry’s plan had overly concentrated on Seoul and its surrounding cities, neglecting other sources of dust across the country and the fact that air has no territorial boundaries.

According to the report, the pollutants emitted in the coal, steel and thermoelectric power plants in South Chungcheong Province impacted the air quality of the capital area from July-October, contributing to creating up to 21 percent of fine dust and up to 28 percent of ultrafine dust.

But the Environment Ministry has not included the plants in its monitoring list of key sites causing fine dust, the audit agency said.

The agency also found that some 17 out of 108 fine dust sensors detecting dust levels had not lived up to the standards with a margin of error of more than 10 percent. For the ultrafine dust sensors, 35 out of 65 devices did not work properly, raising questions over their credibility to measure the air quality.

The Environment Ministry also wrongly assessed the amount of fine dust it cut in 2014, touting itself as over-accomplishing its target to slash 8,567 ton of fine dust. The ministry said it had reduced 15,859 tons in its assessment report, but it actually cut 8,360 tons of dust.

The audit agency identified 18 different areas for the ministry to fix the flawed system.

A dust particle smaller than 10 micrometers in diameter is classified as fine dust, while a particle smaller than 2.5 micrometers in diameter is classified as ultrafine dust.

By Ock Hyun-ju (laeticia.ock@heraldcorp.com)