separate institutions.
84. Legislations must be dynamic and applicable even to the rapidly chanpinh technolopical advancement. They should be reviewed and revised at least every
five years to ensure that they continue to serve the purpose intended. If
the present situation is left to continue, environmental difficultiesare bound to erupt which may be too costly to solve.35. African countries should ensure that the enforcement bodies established to implement legislations on pollution are i_-iven optimum sir-port so that proner facilities are set up for the monitoring of environmental protection efforts or degradation. The major problem: for the future is to allow
industrial development to occur outside the framework of the environment
protection system. Before any project is implemented, it is necessary to assess the impact of all the components of tho proposed -roject on the physical,
biological and social environment, t hrough environmental impact assessment(EIA) studies,
Standards for air quality, water quality and ecological degradation 86. A standard is a technical document available f> the public, drawn up v;ith the cooperation and consensus or general r—roval of all interests
affected by it based on the consolidated results of science, technology and experienccj aimed at the promotion of optimum community benefits and approved by a body recornized on the national, regional or international level. A
standard may take the form of:
(a) a document containing a set of conditions to '--e. fulfilled; . (b) method of sampling or inspection;
(c) method o^ tost or analysis;
(d) code of practice including, instruction and operation manuals, byelaws, etc;
(e) forms and contract forms.
E/ECA/ENV/17 Page "34
37. Experience has shown that nost standards cr v-'rV.uct specifications can be implemented uy industries voluntarily 1-.?cause t'ic benefits arc immediate and tangible. The standards relating to health, ^ccir-ational safety, environmental protection, cneivy conservations, consumer ■.rotocti^n arc viewer by industry as a cost an-, are of interest to rovernm^nt alone. Nothin- short if mandatory enforcement of such standards would encourage industry t^ corrly with the
standards. Standards vt air \uality. witor :uMlity and oc^.'ofjical degradation fall in the category of standards th?t soul' be enforced, mandatorily if industry and larTe scale estate farmers are to com;, ly.
Standards for air juality
88. There are a number of ways of utilizing standards to maintain or achieve a ^re-determined level of air quality and thereby limit the exposure of ■
populations, ecosystems, etc. to air pollutants. The two nest cc-nmon tyoes of standards are ambient air quality jt\c omissirn standards:
air quality standards
Ambient air quality standards are limits placed on levels of air oollutants in the ambient air during a (;ivcn -eriod of time, ^.osirned to achieve air
ouality objectives or an acceptable level of air quality. Although what is considered, to bo acceptable may vary fror country to country, there are upner and lower ^ui^eline concentrations. For example, air can never have a
concentration of any substance' l^wer than the '-lobal back-xoun^ concentration of that substance, so standards nust be ,-reator than chose levels (see Table IV). On the other hand, standards should be set at levels below those known to represent a substantial danger to human health, aquatic life "x ve^ctstion.
The WHO issued guidance on harmful levels for st-mo oollutants and "'rorosed the concentration shown in Table V as lonq-term ^oals intense-1 to prevent undesirable effects from sulphur rxid.es and sus^endc-! v-articulatcs. carbon iron^xi'V and
rhotochemical oxidants. Table VI wives a f:om"Tlatinn of guidelines on ancient air nuality standards "derived froi? 3 recent stu !y of wc^rl-" wi-'o air quality management stand.arcfeby Martin and Stoin. It v/as ^nun1. from the study that the USSR was the first country to set air quality standards in 1951 and by 1973 had standards for 13'1. substances. These air qv.a] Lty stan'ar's represent the minimup. nollutant concentrations tolerable by man or test animals and are used by several eastern European countries.
(b) Emission standards
(i) Emission standards for stationary sources arc limits syecifyin^
maximum allowable levels of pollutants in discharge fron a site, -)rocessf chimnev, v^nt, etc. with the intention of hel^inc; to achieve a desired quality. As v;ith ami lent air duality standards, emission standards are .vften a reflection of not only technological
(i.e. process and equionent) considerations but also eccn:?iic, sociological and 'political c'nsi.'.erations. Snission standar-.'s may be either ^fficiolly prorpul atod or "resumptive.
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Page ^°
Table IV: Sources and background concentrations of selected pollutants
Pollutant Natural source
Background concentration
(ug/m )
Sulphur dioxide Hydrogen sulphide Nitric oxide
Nitrogen dioxide
Ammonia
Carbon monoxide
Ozone
Hydrocarbons
Reactive
volcanoes
volcanoes; Molo.-ical decay Dacterial action in soil, T-shotodissociation of N20
and N02
Bacterial action in soil oxidation of NO
Biological -^ecay Oxidation of nethane;
^hotod.issociation of C0_:
forest fires; oceans
Trooos;)heric reactions and transport from stratosrhere Biological processes in
swamps
Biol^^ical orocessos in forests
1 - i 0.3
0.3 - 2.5
0.2- 2.5
4 100
20 - 60
CH^ = 1000 non-CH. 1
E/ECA/ENV/17
Table V: Guideline tolerances rec:;tt!nendo-J for lon^-term
Pollutant
Measurement
Tolerance level tig /n )
Sulphur., oxides2
Suspended
^articulates2
Carbon moncxic'e
Dhotocheinical-oxidant
British Standard
British Standard
Nondispersive infra-red
measured by neutral buffered KI method expressed as ozone
Annual noan A