Table 2 : Classification of air pollutants in Norway

Compound	Effect on	Averaging time		Classification criterion
SO2	health, materials and vegetation	1 day	100 ug/m3
		6 months	30 ug/m3
Seat	health	1 day	100 ug/m3	high limit
		6 months	40 ug/m3	high limit
		6 months	20 ug/m3	high limit
NO2	health	1 hour	200 ug/m3
		1 day	100 ug/m3
		6 months	75 ug/m3
CO	health	1 hour	25 mg/m3
		8 hours	10 mg/m3
O3	health and vegetation	1 hour	120 ug/m3
F	vegetation and animals	1 day	1.0 ug/m3	gaseous F
		1 month	0.2 ug/m3	total F
		6 months	0.3 ug/m3	gaseous F
Dustfall	Welfare	1 month	5 g/m2
S	Acidification	1 year	0.5 g/m2

Discussion And Conclusions

Monitoring of concentrations and effects of different air pollutants is necessary for prevention and control of air pollution. Without data on concentrations and effects, there is no possibility of studying the occurrance and distribution of air pollutants and their effects in place and time, of setting standards for the protection of man and his environment, and of checking the results of abatement measures. What we need is an alarm system in order to prevent the occurance of excessive concentrations, resulting in hazardous effects on man, other animals, plants and materials. For these purposes both physical/chemical concentration measurements along with biological effect measurements with plants are needed. The concentrations measured by physico-chemical methods are not sufficient to predict all possible of air pollutants, and indicator plants will never be able to give information about identity and concentration of all polluting agents in air. There is no question of replacing ambient air monitoring by physical/chemical methods with effect-monitoring with plants ; both should be used jointly. Ambient concentration measurements, effect intensity measurements on plants (including chemical/physical leaf analysis), and measurements of meterological parameters, may together produce the total picture of the pollution situation (Posthumus,1984).

The work discussed earlier proves that plants can be used for the purpose of air monitoring as a cheap instrument and technique is easy for adoption. The biological-effect monitoring network regularly spread all over the country can be set up in close co-operation with other air quality monitoring network. The sensitive indicator and/or accumulator plants could be used in a standardised way. The need for the formulation of a national programme on the use of bioindicators for air quality is, therefore, strongly felt.

REFERENCES

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