ការព្យាករណ៍គុណភាពខ្យល់
ទិន្នន័យគុណភាពខ្យល់ផ្តល់ដោយ៖ Eesti välisõhu kvaliteet - Estonian ambient air quality (airviro.klab.ee)
Note that the measurements for O3 (ozone) and NO2 (nitrogen dioxide) are taken from the station: Narva and the measurement for SO2 (sulfur dioxide) are taken from the station: Sinimäe