English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

The increasing use of intensive agricultural practices can lead to damaging consequences for the atmosphere through enhanced emissions of air pollutants. However, there are few direct measurements of the surface–atmosphere exchange of trace gases and water-soluble aerosols over agricultural grassland, particularly of reactive nitrogen compounds. In this study, we present measurements of the concentrations, fluxes and deposition velocities of the trace gases HCl, HONO, HNO3, SO2 and NH3 as well as their associated water-soluble aerosol counterparts Cl, NO−2 , NO−3 , SO 2− 4 and NH + 4 as determined hourly for 1 month in May–June 2016 over agricultural grassland near Edinburgh, UK, preand postfertilisation. Measurements were made using the Gradient of Aerosols and Gases Online Registrator (GRAEGOR) wet-chemistry two-point gradient instrument. Emissions of NH3 peaked at 1460 ngm−2 s−1 3 h after fertilisation, with an emission of HONO peaking at 4.92 ngm−2 s−1 occurring 5 h after fertilisation. Apparent emissions of NO−3 aerosol were observed after fertilisation which, coupled with a divergence of HNO3 deposition velocity (Vd) from its theoretical maximum value, suggested the reaction of emitted NH3 with atmospheric HNO3 to form ammonium nitrate aerosol. The use of the conservative exchange fluxes of tot-NH+4 and tot-NO − 3 indicated net emission of tot-NO−3 , implying a ground source of HNO3 after fertilisation. Daytime concentrations of HONO remained above the detection limit (30 ngm−3) throughout the campaign, suggesting a daytime source for HONO at the site. Whilst the mean Vd of NH+4 was 0.93 mms −1 in the range expected for the accumulation mode, the larger average Vd for Cl (3.65 mms−1), NO−3 (1.97 mms −1) and SO2− 4 (1.89 mms −1) reflected the contribution of a supermicron fraction and decreased with increasing PM2.5/PM10 ratio (a proxy measurement for aerosol size), providing evidence – although limited by the use of a proxy for aerosol size – of a size dependence of aerosol deposition velocity for aerosol chemical compounds, which has been suggested from process-orientated models of aerosol deposition.

atmospheric chemistry and physics

Surface–atmosphere exchange of inorganic water-soluble gases and associated ions in bulk aerosol above agricultural grassland pre- and postfertilisation