NO2 Flashcards
Why is NO2 the most important air pollutant?
Its ubiquity in ambient air and high toxicity.
Why is NO2 significant in the troposphere?
Production of photochemical oxidants and acidic deposition.
What is the photolytic cycle of NO2?
UV breakdown into NO and O, O reaction with O2 forming O3, O3 reacting with NO forming NO2 and O2.
What do plants uptake Nox?
through stomata, NO2 more rapidly than NO due to its reaction with water.
What then happens within the plant?
Conversion to nitrate and nitrite
What causes NO2-induced plant injuries?
Acidification or photooxidation.
How does acidification result?
Nitrate ions can assimilate into amino acids in protein synthesis, or stored in vacuoles and transported across the plant, where through microbial nitrification, conversion into nitric acid and nitrous acid acidifies the plant.
How do NO2-induced injuries differ from SO2?
Higher concentrations of NO2 are required to damage plants.
How does Nox inhibit photosynthesis?
Competition for NADPH between nitrite reduction and carbon assimilation in chloroplasts.
How does NO2 act on animals?
Mainly through deep lungs and peripheral airways through fibrin formation in airways, increasing macrophages, with loss of cilia in terminal bronchioles
What happens following NO2 inhalation?
ts conversion to NO and NO3
How can these impact the body?
NO is a vasodilator, neutrotransmitter, and is important in immune responses, excessive levels causing inflammation and oxidative stress.
How is NO mitigated?
Metabolising by NO synthase, converted into less reactive species that are excreted.
What atmospheric interactions does NO2 have important to humans?
As a greenhouse gas and destroying O3
How is N2O removed from atmosphere?
Photolysis and excited O2 reaction, with a 120 year lifespan.
