Correlations between 7Be, 210Pb, dust and PM10 concentrations in relation to meteorological conditions in northern Poland in 1998-2018

Analysis of a twenty-year (1998-2018) data series on ⁷Be concentrations in weekly collected aerosol samples in northern Poland showed a clear pattern of seasonal changes in ⁷Be with a maximum in the summer period associated with the most intensive thermal convection and vertical mixing. Activity concentrations of ⁷Be ranged from 480 μBq m^-3 to 9370 μBq m^-3. A strong relationship has been shown between ⁷Be concentrations observed in years and the activity of the Sun related to the sunspot number. Activity concentrations of ²¹⁰Pb in aerosol ranged from 17 μBq m^-3 to 1490 μBq m-3 with maximum occurring in the winter. The difference in the seasonal pattern in ⁷Be and ²¹⁰Pb concentrations were directly related to the different sources of both isotopes, as an additional source of ²¹⁰Pb was the products of combustion during the heating season. Similar pattern with maximum concentrations in winter was observed for PM10, as the main source is the same as in the case ²¹⁰Pb. A content of PM10 was in the range from 6.5 to 81.7 μg m^-3. A statistically significant correlation between both isotopes occurs. At the same time, ⁷Be, ²¹⁰Pb and PM10 are visibly related to the dust concentrations ranged from 7.3 μg m^-3 in winter to 134.8 μg m^-3 in spring. Statistical analysis carried out with simple regression model, stepwise multiple regression, and Random Forest models showed that the sunspots number, air temperature and sunshine duration have the most substantial impact on transport, and hence the concentration of ⁷Be in the surface layer of the atmosphere. The increase in relative humidity and precipitation and higher wind speed have a statistically significant effect on the reduction of ⁷Be concentrations in surface air.

Optimized low-level liquid scintillation spectroscopy of 35S for atmospheric and biogeochemical chemistry applications

Anthropogenic activities, dominated by emissions of sulfur dioxide (SO(2)), have perturbed the global sulfur (S) cycle. Uncertainties in timescales of S transport and chemistry in the atmosphere lead to uncertainties in the predicted impact of S emissions. Measurements of cosmogenic (35)S may potentially be used to resolve existing uncertainties in the photochemical and chemical transformation of S in the environment. The lack of a simple, effective, and highly sensitive technique to measure (35)S activity in samples with low activities may explain the scarcity of published measurements. We present a set of new sample handling and measurement procedures optimized for the measurement of (35)S in natural samples with activities as low as 0.20 dpm above background (2sigma, integration time = 2 hr). We also report simultaneous measurements of aerosol (35SO4 ) and gas phase (35SO2) collected at inland and coastal locations; the range of observed activities corresponds to SO(2) residence lifetimes of 0.2 +/- 0.04 (coastal) - 22.3 d +/- 0.04 (inland). These optimized techniques offer the potential for resolving atmospheric processes that occur on 6-12-hour timescales as well as resolving transport phenomena such as stratospheric mixing into the troposphere.