RESUMO
In this article, the authors apply the relative air pollution index (RAPI) proposed by Pham Ngoc Ho for aggregate assessment of daily air pollution level (RAPId) using data from 3 daily standards (1, 8, and 24 h) of each country's standard, including Vietnam Technical Regulation QCVN 05:2013/MONRE. By using the automated data of ambient air at 3 monitoring stations in Cam Pha coal mining area, Quang Ninh province in 2018, results of the frequency of pollution by month (f%) have shown that overall, the air quality in dry season (October-March) is worse than that in rainy season (April-September). Results of pollution frequency by month in a year f% also indicate that air pollution in 2018 at 3 stations is mostly at level I (no pollution) with f% ranged from 10 to 58.3%, but pollution level II-IV (light pollution-very heavy pollution) also happened as f% fluctuated from 20 to 42% in some months. Comparing with air quality assessment in 2011-2015 at this area by periodic monitoring equipment of Quang Ninh Center for Environmental Monitoring, results in 2018 have shown that individual index of RAPI is consistent with the current status of air quality with high accuracy. To compare with RAPId, we used VN_AQId index of the Vietnam Environment Administration (VEA). Comparison results show that both indices do not encounter eclipsing effect. However, ambiguous effect occurred in the case of VN_AQId index (warning not suitable for reality in some cases). In addition, advantages and limitations of these two methods have been analyzed and explained in detail.