Stable isotopic characterization of nitrate wet deposition in the tropical urban atmosphere of Costa Rica

• Published in: Environmental science and pollution research international 2021-12, Vol.28 (47), p.67577-67592
• Main Authors: Villalobos-Forbes, Mario, Esquivel-Hernández, Germain, Sánchez-Murillo, Ricardo, Sánchez-Gutiérrez, Rolando, Matiatos, Ioannis
• Format: Article
• Language: English
• Subjects: air; Air masses; Anthropogenic factors; Aquatic ecosystems; Aquatic Pollution; Atmosphere; Atmospheric chemistry; Atmospheric Protection/Air Quality Control/Air Pollution; Bayes Theorem; Bayesian analysis; Bayesian theory; biomass; Biomass burning; Burning; Composition; Costa Rica; Deposition; Earth and Environmental Science; Ecosystem; Ecotoxicology; Emissions; energy; Energy consumption; Environment; Environmental Chemistry; Environmental Health; Environmental Monitoring; Environmental science; Food consumption; Food production; Fractionation; Gasoline; Hydrometeorology; Isotopes; lightning; Nitrates; Nitrates - analysis; Nitrogen; Nitrogen Isotopes - analysis; Oxidation; Oxygen Isotopes - analysis; Precipitation; rain; Rainfall; Research Article; Stable isotopes; Trajectory analysis; Tropical environment; Tropical environments; Urban atmosphere; Urban environments; Waste Water Technology; Water Management; Water Pollutants, Chemical - analysis; Water Pollution Control; Wet deposition
• ISSN: 0944-1344; 1614-7499
• DOI: 10.1007/s11356-021-15327-x

Increasing energy consumption and food production worldwide results in anthropogenic emissions of reactive nitrogen into the atmosphere. To date, however, little information is available on tropical urban environments where inorganic nitrogen is vastly transported and deposited through precipitation on terrestrial and aquatic ecosystems. To fill this gap, we present compositions of water stable isotopes in precipitation and atmospheric nitrate (δ 18 O-H 2 O, δ 2 H-H 2 O, δ 15 N-NO 3 - , and δ 18 O-NO 3 - ) collected daily between August 2018 and November 2019 in a tropical urban atmosphere of central Costa Rica. Rainfall generation processes (convective and stratiform rainfall fractions) were identified using stable isotopes in precipitation coupled with air mass back trajectory analysis. A Bayesian isotope mixing model using δ 15 N-NO 3 - compositions and corrected for potential 15 N fractionation effects revealed the contribution of lightning (25.9 ± 7.1%), biomass burning (21.8 ± 6.6%), gasoline (19.1 ± 6.4%), diesel (18.4 ± 6.0%), and soil biogenic emissions (15.0 ± 2.6%) to nitrate wet deposition. δ 18 O-NO 3 - values reflect the oxidation of NO x sources via the ·OH + RO 2 pathways. These findings provide necessary baseline information about the combination of water and nitrogen stable isotopes with atmospheric chemistry and hydrometeorological techniques to better understand wet deposition processes and to characterize the origin and magnitude of inorganic nitrogen loadings in tropical regions.