The impact of temperature inversions on black carbon and particle mass concentrations in a mountainous area

Abstract

Abstract. Residential wood combustion is a widespread practice in Europe with a serious impact on air quality, especially in mountainous areas. While there is a significant number of studies conducted in deep urbanized valleys and basins, little is known about the air pollution processes in rural shallow hollows where around 30 % of the people in mountainous areas across Europe live. We aim to determine the influence of ground temperature inversions on wood combustion aerosol pollution in hilly, rural areas. The study uses Retje karst hollow (Loški Potok, Slovenia) as representative site for mountainous and hilly rural areas in central and southeastern Europe with residential wood combustion. Sampling with a mobile monitoring platform along the hollow was performed in December 2017 and January 2018. The backpack mobile monitoring platform was used for the determination of equivalent black carbon (eBC) and particulate matter (PM) mass concentrations along the hollow. To assure high quality of mobile measurement data, intercomparisons of mobile instruments with reference instruments were performed at two air quality stations during every run. Our study showed that aerosol pollution events in the relief depression were associated with high local emission intensities originating almost entirely from residential wood burning and shallow temperature inversions (58 m on average). The eBC and PM mass concentrations showed stronger associations with the potential temperature gradient (R2 = 0.8) than with any other meteorological parameters taken into account (ambient temperature, relative humidity, wind speed, wind direction and precipitation). The strong association between the potential temperature gradient and pollutant concentrations suggests that even a small number of emission sources (total 243 households in the studied hollow) in similar hilly and mountainous rural areas with frequent temperature inversions can significantly increase the levels of eBC and PM, and deteriorate local air quality. During temperature inversions the measured mean eBC and PM2.5 mass concentrations in the whole hollow were as high as 4.5 ± 2.6 µg m–3 and 48.0 ± 27.7 µg m–3, respectively, which is comparable to larger European urban centres.

The impact of atmospheric motions on source-specific black carbon and the induced direct radiative effects over a river-valley region

“…The averaged mass concentration was comparable with that in Lanzhou, another river-valley city in China that was sampled in the same season (5.1 ± 2.1, Zhao et al, 2019). The lowest value is comparable with other river-valley regions such as in Retje in India (Glojek et al, 2022) or in the Urumqi River valley in China ; however, even the highest concentration was much lower than that in other urban regions (Table S5).…”

“…In this way, pollutants can accumulate in valleys and spread throughout the area, thereby aggravating pollution. In addition, temperature inversions commonly form in river valleys during the winter, and that, too, can aggravate pollution problems (Glojek et al, 2022;Bei et al, 2016).…”

Enviro-HIRLAM model estimates of elevated black carbon pollution over Ukraine resulted from forest fires

“…Frequent and strong air temperature inversions determined deposition during August 2010. Its influence during the stationary anticyclone was compared to the impact of low-level temperature inversions in areas with complex terrain, such as Slovenia (Glojek et al, 2022). These conditions defined diurnal variations of BC and its vertical profiles.…”

High-Resolution Emissions From Wood Burning in Norway - The Effect of Cabin Emissions

“…Taking into account that the occupancy of holiday houses is much lower than that in primary houses, wood combustion for heating represents an intensive activity in short periods of time. In mountain areas for instance, and those affected by intense tourism activities, it represents the largest energy source for heating, which emissions, intensified by temperature inversions and topography, result in high pollution episodes and additional environmental impacts (e.g., [33][34][35]). Moreover, wood burning is one of the largest sources of black carbon [36], and its deposition in snow, along with dust, has been estimated to be responsible of advanced snowmelt of around 17 days on average in mountain areas such as the Alps and Pyrenees [37], with subsequent impact on mountain ecosystems, water resources and society.…”