Ammonia (NH 3 ) in the atmosphere is one of the main causes of acid deposition and formation of PM2.5 particulate matter. Its monitoring is performed in many air quality monitoring networks including Acid Deposition Monitoring Network in East Asia (EANET). To obtain information about spatial distribution of ammonia, data retrieved from IASI instrument aboard MetOp-A satellite was used in this study. It was shown that remote sensing data and near surface ammonia measurements at EANET sites in

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... t EANET sites in Baikal region are in a good agreement for all the seasons except winter. Mean spring, summer and fall concentrations at 1×1° grid in Baikal region were calculated for the years from 2015 to 2017. Mean spring amount of ammonia near the surface is not high for the whole region. However, in summer and fall there are areas where concentrations far exceed background levels. These areas are mainly located closely to Lake Baikal and in Evenk District of Krasnoyarsky Krai. The most intensive forest fires registered by MODIS instrument measurements during the considered period occurred in same areas. It allows suggesting that the main sources of ammonia in atmosphere in the considered region are forest fires.