Impact assessment of anhtropogenic activities on air quality of Ulaanbaatar, Mongolia using lichen as the bioindicator

Abstract

Lichen is a composite organism that arises from green algae or cyanobacterium (phycobiont) and fungal partner belongs to the Ascomycota and Basidiomycota (mycobiont), living together in symbiotic relationship. The interaction between lichens and air pollution has been used as a means of monitoring air quality since 1859. The most important pollutant was sulphur dioxide produced by coal burning industry and power stations. City of Ulaanbaatar, the capital of Mongolia was initially designed for a half million residents. Due to intense rural-to-urban migration after transition to market driven economy, the population of the capital is nearly tripled, which resulted in huge area of informal settlements and elevated number of vehicles. Tents and small buildings in above settlements heated by conventional stoves by burning coal and wood, while the most vehicles on the road are imported second-hand cars. During last two decades, air quality of capital city Ulaanbaatar is considered as an emerging issue and above two are primary sources of outdoor air pollution. The most abundant air pollutants are nitrogen dioxide (NO2), sulfur dioxide (SO2) and carbon monoxide (CO) which have disastrous effects on health when inhaled over prolonged periods of time. Due to the quantities of these pollutants would be far more abundant and thus cause the catastrophic effects to the air quality that is seen in Ulaanbaatar. Various techniques have been developed to monitor air quality, including biomonitoring using lichens. In this study, we monitored types of epiphytic lichens covering sensitive to air pollution fruticose type and relatively tolerant foliose type of lichens. Unlike air quality index, lichens clearly show negative impact of poor air quality on surrounding ecosystems. We examined lichens on Larix sibirica, the most abundant coniferous tree of the area. Both foliose and fruticose types of lichens are abundant in Larix sibirica dominated forests located to the northern areas of Ulaanbaatar. It indicates the area is free of pollution. In contrary, fruticose type lichens, especially representatives from the genera Usnea, Cladonia and Vulpicidia are absent in coniferous forest to the southern areas of Ulaanbaatar. These results clearly show downwind ecosystems have been badly affected by poor quality air of the capital. Additionally, there is none of those bark dwelling lichens are observed on the three along the crowded roads, parks and residential areas which indicates the extreme pollution of the air. Finally, biomonitoring using lichen as the bioindicator is discussed, and future recommendation is provided in the end of the study.

Lichen is a composite organism that arises from green algae or cyanobacterium (phycobiont) and fungal partner belongs to the Ascomycota and Basidiomycota (mycobiont), living together in symbiotic relationship. The interaction between lichens and air pollution has been used as a means of monitoring air quality since 1859. The most important pollutant was sulphur dioxide produced by coal burning industry and power stations. City of Ulaanbaatar, the capital of Mongolia was initially designed for a half million residents. Due to intense rural-to-urban migration after transition to market driven economy, the population of the capital is nearly tripled, which resulted in huge area of informal settlements and elevated number of vehicles. Tents and small buildings in above settlements heated by conventional stoves by burning coal and wood, while the most vehicles on the road are imported second-hand cars. During last two decades, air quality of capital city Ulaanbaatar is considered as an emerging issue and above two are primary sources of outdoor air pollution. The most abundant air pollutants are nitrogen dioxide (NO2), sulfur dioxide (SO2) and carbon monoxide (CO) which have disastrous effects on health when inhaled over prolonged periods of time. Due to the quantities of these pollutants would be far more abundant and thus cause the catastrophic effects to the air quality that is seen in Ulaanbaatar. Various techniques have been developed to monitor air quality, including biomonitoring using lichens. In this study, we monitored types of epiphytic lichens covering sensitive to air pollution fruticose type and relatively tolerant foliose type of lichens. Unlike air quality index, lichens clearly show negative impact of poor air quality on surrounding ecosystems. We examined lichens on Larix sibirica, the most abundant coniferous tree of the area. Both foliose and fruticose types of lichens are abundant in Larix sibirica dominated forests located to the northern areas of Ulaanbaatar. It indicates the area is free of pollution. In contrary, fruticose type lichens, especially representatives from the genera Usnea, Cladonia and Vulpicidia are absent in coniferous forest to the southern areas of Ulaanbaatar. These results clearly show downwind ecosystems have been badly affected by poor quality air of the capital. Additionally, there is none of those bark dwelling lichens are observed on the three along the crowded roads, parks and residential areas which indicates the extreme pollution of the air. Finally, biomonitoring using lichen as the bioindicator is discussed, and future recommendation is provided in the end of the study.