WHO has recommended an annual average guideline of 40 Tg/m3 (WHO, 1996)

Although there is no particular study or set of studies that support a numerical value,

the WHO=s database clearly indicates the need to protect the public from chronic

exposures. For example, indoor air studies with strong NO2 sources (e.g. gas stoves)

suggest that an increment of about 30 Tg/m3 (two week average) is associated with a

20 % increase in lower respiratory illness of children 5 to 12 years old. However, the

effected children had a pattern of indoor exposure that included peak exposures higher

than those typically encountered outdoors. Thus, they cannot be extrapolated

quantitatively to outdoor air pollution. Outdoor epidemiological studies suggest a

range of potential effects, providing support for the indoor studies, although they do

not provide consistent exposure information for NO2. Furthermore, animal

toxicological studies show that prolonged exposures can cause decreases in lung host

defences and changes in lung structure. Based on expert judgement 40 Tg/m3 is proposed

as an annual average guideline.

 

 

 

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

 

     Flag of Portugal 

 english:

 castellano: DISPER CUSTIC DESCAR RADIA    italiano:     

 

 français:    português:  

 

deutsch:

 

 

 

deutsch: DIS CUS  DES  RAD

castellano: DIS CUS DES  RAD   english: DIS CUS DES RAD  

 

 português: DIS CUS DES RAD   italiano:   DIS CUS  DES RAD

 

français:  DIS CUS DES RAD