The atmospheric chemistry of oxidised nitrogen compounds is complicated, since they

take part in a large number of chemical reactions and may be converted into a number

of different chemical compounds. NO emissions are oxidised in the atmosphere to

NO2 and further to nitric acid/nitrate. NO2 is present in urban air at concentrations

between a few tenths to several hundreds of Tg/m;. Concentrations in rural areas are

generally much lower and vary with distance from source. The concentration of NO2

is a complex function of the meteorological situation, the emission rate of nitrogen

oxides, the oxidation of NO to NO2 and the oxidation rate of NO2 to other species.

Dispersion, deposition and chemical transformation cause the concentration of

nitrogen oxides to decrease with distance from an emission source.

The cycle of nitrogen compounds is shown in figure 1.2.

 

 

 

401 - 402 - 403 - 404 - 405 - 406 - 407 - 408 - 409 - 410 - 411 - 412 - 413 - 414 - 415 - 416 - 417 - 418 - 419 - 420 - 421 - 422 - 423 - 424 - 425 - 426 - 427 - 428 - 429 - 430 - 431 - 432 - 433 - 434 - 435 - 436 - 437 - 438 - 439 - 440 - 441 - 442 - 443 - 444 - 445 - 446 - 447 - 448 - 449 - 450

 

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