Because winds can vary with height, determining the steering flow precisely can be difficult. The pressure altitude at which the background winds are most correlated with a tropical cyclones motion is known as the "steering level". The motion of stronger tropical cyclones is more correlated with the background flow averaged across a thicker portion of troposphere compared to weaker tropical cyclones whose motion is more correlated with the background flow averaged across a narrower extent of the lower troposphere. When wind shear and latent heat release is present, tropical cyclones tend to move towards regions where potential vorticity is increasing most quickly.Climatologically, tropical cyclones are steered primarily westward by the east-to-west trade winds on the equatorial side of the subtropical ridge—a persistent high-pressure area over the worlds subtropical oceans. In the tropical North Atlantic and Northeast Pacific oceans, the trade winds steer tropical easterly waves westward from the African coast toward the Caribbean Sea, North America, and ultimately into the central Pacific Ocean before the waves dampen out. These waves are the precursors to many tropical cyclones within this region. In contrast, in the Indian Ocean and Western Pacific in both hemispheres, tropical cyclogenesis is influenced less by tropical easterly waves and more by the seasonal movement of the Intertropical Convergence Zone and the monsoon trough. Other weather systems such as mid-latitude troughs and broad monsoon gyres can also influence tropical cyclone motion by modifying the steering flow.
2
          
          
            NaNO
            
              2
            
            
              
            
          
          ⟶
          
            Na
            
              2
            
            
              
            
          
          O
          +
          NO
          +
          
            NO
            
              2
            
            
              
            
          
        
      
    
    {\displaystyle {\ce {2 NaNO2 -> Na2O + NO + NO2}}}
  Sodium nitrite can also be used in the production of nitrous acid:

  
    
      
        
          2
          
          
            NaNO
            
              2
            
            
              
            
          
          +
          
            H
            
              2
            
            
              
            
          
          
            SO
            
              4
            
            
              
            
          
          ⟶
          2
          
          
            HNO
            
              2
            
            
              
            
          
          +
          
            Na
            
              2
            
            
              
            
          
          
            SO
            
              4
            
            
              
            
          
        
      
    
    {\displaystyle {\ce {2NaNO2 + H2SO4 ->2 HNO2 + Na2SO4}}}
  The nitrous acid then, under normal conditions, decomposes:

  
    
      
        
          2
          
          
            HNO
            
              2
            
            
              
            
          
          ⟶
          
            NO
            
              2
            
            
              
            
          
          +
          NO
          +
          
            H
            
              2
            
            
              
            
          
          O
        
      
    
    {\displaystyle {\ce {2 HNO2 -> NO2 + NO + H2O}}}
  The resulting nitrogen dioxide hydrolyzes to a mixture of nitric and nitrous acids:

  
    
      
        
          2
          
          
            NO
            
              2
            
            
              
            
          
          +
          
            H
            
              2
            
            
              
            
          
          O
          ⟶
          
            HNO
            
              3
            
            
              
            
          
          +
          
            HNO
            
              2
            
            
              
            
          
        
      
    
    {\displaystyle {\ce {2 NO2 + H2O -> HNO3 + HNO2}}}

Isotope labelling 15N
In organic synthesis isotope enriched sodium nitrite-15N can be used instead of normal sodium nitrite as their reactivity is nearly identical in most reactions.