Springtime nitrogen oxides and tropospheric ozone in Svalbard: results from the measurement station network

Svalbard is a remote and scarcely populated Arctic archipelago and is considered to be mostly influenced by long-range-transported air pollution. However, there are also local emission sources such as coal and diesel power plants, snowmobiles and ships, but their influence on the background concentrations of trace gases has not been thoroughly assessed. This study is based on data of tropospheric ozone (O3) and nitrogen oxides (NOx) collected in three main Svalbard settlements in spring 2017. In addition to these ground-based observations and radiosonde and O3 sonde soundings, ERA5 reanalysis and BrO satellite data have been applied in order to distinguish the impact of local and synoptic-scale conditions on the NOx and O3 chemistry. The measurement campaign was divided into several sub-periods based on the prevailing large-scale weather regimes. The local wind direction at the stations depended on the large-scale conditions but was modified due to complex topography. The NOx concentration showed weak correlation for the different stations and depended strongly on the wind direction and atmospheric stability. Conversely, the O3 concentration was highly correlated among the different measurement sites and was controlled by the long-range atmospheric transport to Svalbard. Lagrangian backward trajectories have been used to examine the origin and path of the air masses during the campaign.publishedVersio

Uncertainties in assessing the environmental impact of amine emissions from a CO 2 capture plant

In this study, a new model framework that couples the atmospheric chemistry transport model system WRF-EMEP and the multimedia fugacity level III model was used to assess the environmental impact of amine emissions to air from post-combustion carbon dioxide capture. The modelling framework was applied to a typical carbon capture plant artificially placed at Mongstad, west coast of Norway. WRF-EMEP enables a detailed treatment of amine chemistry in addition to atmospheric transport and deposition. Deposition fluxes of WRF-EMEP simulations were used as input to the fugacity model in order to derive concentrations of nitramines and nitrosamine in lake water. Predicted concentrations of nitramines and nitrosamines in ground-level air and drinking water were found to be highly sensitive to the description of amine chemistry, especially of the night time chemistry with the nitrate (NO3) radical. Sensitivity analysis of the fugacity model indicates that catchment characteristics and chemical degradation rates in soil and water are among the important factors controlling the fate of these compounds in lake water. The study shows that realistic emission of commonly used amines result in levels of the sum of nitrosamines and nitramines in ground-level air (0.6–10 pgm−3) and drinking water (0.04–0.25 ngL−1) below the current safety guideline for human health enforced by the Norwegian Environmental Directorate. The modelling framework developed in this study can be used to evaluate possible environmental impacts of emissions of amines from post-combustion capture in other regions of the world

Ground-based measurements of total ozone column amount with a multichannel moderate-bandwidth filter instrument at the Troll research station, Antarctica

Combining information from several channels of the Norwegian Institute for Air Research (NILU-UV) irradiance meter, one may determine the total ozone column (TOC) amount. A NILU-UV instrument has been deployed and operated on two locations at Troll research station in Jutulsessen, Queen Maud Land, Antarctica, for several years. The method used to determine the TOC amount is presented, and the derived TOC values are compared with those obtained from the Ozone Monitoring Instrument (OMI) located on NASA’s AURA satellite. The findings show that the NILU-UV TOC amounts correlate well with the results of the OMI and that the NILU-UV instruments are suitable for monitoring the long-term change and development of the ozone hole. Because of the large footprint of OMI, NILU-UV is a more suitable instrument for local measurements.publishedVersio

Impact of forest fires, biogenic emissions and high temperatures on the elevated Eastern Meditteranean ozone levels during the hot summer of 2007

The hot summer of 2007 in southeast Europe has been studied using two regional atmospheric chemistry models; WRF-Chem and EMEP MSC-W. The region was struck by three heat waves and a number of forest fire episodes, greatly affecting air pollution levels. We have focused on ozone and its precursors using state-of-the-art inventories for anthropogenic, biogenic and forest fire emissions. The models have been evaluated against measurement data, and processes leading to ozone formation have been quantified. Heat wave episodes are projected to occur more frequently in a future climate, and therefore this study also makes a contribution to climate change impact research. The plume from the Greek forest fires in August 2007 is clearly seen in satellite observations of CO and NO2 columns, showing extreme levels of CO in and downwind of the fires. Model simulations reflect the location and influence of the fires relatively well, but the modelled magnitude of CO in the plume core is too low. Most likely, this is caused by underestimation of CO in the emission inventories, suggesting that the CO/NOx ratios of fire emissions should be re-assessed. Moreover, higher maximum values are seen in WRF-Chem than in EMEP MSC-W, presumably due to differences in plume rise altitudes as the first model emits a larger fraction of the fire emissions in the lowermost model layer. The model results are also in fairly good agreement with surface ozone measurements. Biogenic VOC emissions reacting with anthropogenic NOx emissions are calculated to contribute significantly to the levels of ozone in the region, but the magnitude and geographical distribution depend strongly on the model and biogenic emission module used. During the July and August heat waves, ozone levels increased substantially due to a combination of forest fire emissions and the effect of high temperatures. We found that the largest temperature impact on ozone was through the temperature dependence of the biogenic emissions, closely followed by the effect of reduced dry deposition caused by closing of the plants’ stomata at very high temperatures. The impact of high temperatures on the ozone chemistry was much lower. The results suggest that forest fire emissions, and the temperature effect on biogenic emissions and dry deposition, will potentially lead to substantial ozone increases in a warmer climate

Validation of TROPOMI Surface UV Radiation Product

The TROPOspheric Monitoring Instrument (TROPOMI) onboard the Sentinel-5 Precursor (S5P) satellite was launched on 13 October 2017 to provide the atmospheric composition for atmosphere and climate research. The S5P is a sun-synchronous polar-orbiting satellite providing global daily coverage. The TROPOMI swath is 2600 km wide, and the ground resolution for most data products is 7.2x3.5 km2 (5.6x3.5 km2 since 6 August 2019) at nadir. The Finnish Meteorological Institute (FMI) is responsible for the development and processing of the TROPOMI Surface Ultraviolet (UV) Radiation Product which includes 36 UV parameters in total. Ground-based data from 25 sites located in arctic, subarctic, temperate, equatorial and antarctic areas were used for validation of TROPOMI overpass irradiance at 305, 310, 324 and 380 nm, overpass erythemally weighted dose rate / UV index and erythemally weighted daily dose for the period from 1 January 2018 to 31 August 2019. The validation results showed that for most sites 60–80% of TROPOMI data was within ±20% from ground-based data for snow free surface conditions. The median relative differences to ground-based measurements of TROPOMI snow free surface daily doses were within ±10% and ±5% at two thirds and at half of the sites, respectively. At several sites more than 90% of clear sky TROPOMI data were within ±20% from ground-based measurements. Generally median relative differences between TROPOMI data and ground-based measurements were a little biased towards negative values, but at high latitudes where nonhomogeneous topography and albedo/snow conditions occurred, the negative bias was exceptionally high, from -30% to -65%. Positive biases of 10–15% were also found for mountainous sites due to challenging topography. The TROPOMI Surface UV Radiation Product includes quality flags to detect increased uncertainties in the data due to heterogeneous surface albedo and rough terrain which can be used to filter the data retrieved under challenging conditions

The Arctic

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Utslipp til luft fra Boliden Odda AS. Spredningsberegninger og konsekvensvurderinger av økte utslipp.

NILU - Norsk Institutt for luftforskning har på oppdrag for Boliden Odda AS, utført sprednings- og avsetningsberegninger i forbindelse med utslipp fra sinkproduksjonsanlegget. Studien beregner luftkonsentrasjon og avsetning av svovel (forsuring), og konsentrasjon av metaller/svevestøv ved dagens sinkproduksjon og ved en planlagt utvidelse. Timesmiddel-, døgnmiddel- og årsmiddel-konsentrasjon av SO2 og PM10 er beregnet til å være innenfor grenseverdier og luftkvalitetskriterier ved dagens og utvidet produksjon. Beregningene viser mulig overskridelse av målsetningsverdien for kadmium ved en utvidelse av produksjonen. Utvidelse i produksjon gir et ytterligere bidrag til overskridelsen av tålegrensen (forsuring) i området rundt Odda. Økningen i avsetning forøvrig er beregnet å være i områder hvor tålegrensen er mer robust

Utslipp til luft fra Boliden Odda AS. Reviderte spredningsberegninger og konsekvensvurderinger av økte utslipp.

NILU - Norsk Institutt for luftforskning har på oppdrag for Boliden Odda AS, utført sprednings- og avsetningsberegninger i forbindelse med utslipp fra sinkproduksjonsanlegget. Studien beregner luftkonsentrasjon og avsetning av svovel (forsuring) og konsentrasjon av metaller/svevestøv ved dagens sinkproduksjon og ved en planlagt utvidelse. Timesmiddel-, døgnmiddel- og årsmiddel-konsentrasjon av SO2 og PM10 er beregnet til å være innenfor grenseverdier og luftkvalitetskriterier ved dagens og utvidet produksjon. Beregningene viser mulig overskridelse av målsetningsverdien for kadmium ved en utvidelse av produksjonen. Utvidelse i produksjon gir et ytterligere bidrag til overskridelsen av tålegrensen (forsuring) i området rundt Odda. Økningen i avsetning forøvrig er beregnet å være i områder hvor tålegrensen er mer robust. Rapporten er en revisjon av NILU-rapport 3/2019

Monitoring of the atmospheric ozone layer and natural ultraviolet radiation: Annual report 2014

This is an annual report describing the activities and main results of the monitoring programme “Monitoring of the atmospheric ozone layer and natural ultraviolet radiation” for 2014. The ozone layer was below the long-term mean in spring 2014, but increased in April/May and was close to normal rest of the year. A clear decrease in total ozone above Norway during the period 1979-1997 stopped after 1998 and the ozone layer above Norway now seems to have stabilized

Monitoring of the atmospheric ozone layer and natural ultraviolet radiation: Annual report 2017.

This report summarizes the results from the Norwegian monitoring programme on stratospheric ozone and UV radiation measurements. The ozone layer has been measured at three locations since 1979: in Oslo, Tromsø/Andøya and Ny-Ålesund. The UV measurements started in 1995. The results show that there was a significant decrease in stratospheric ozone above Norway between 1979 and 1997. After that the ozone layer stabilized at a level ~2% below pre-1980 level. There are large inter-annual variations and in 2017 there were relatively low values at all the three Norwegian stations during the winter. However, the ozone situation normalized towards the end of spring