Azura-Edo Independent Power Plant Environmental Impact ... - IFC

The WHO guidelines are particularly conservative and do not consider
economic factors; however they have been employed in this assessment as
they are recommended by the IFC and represent the most conservative
approach. Where Nigerian standards are set out in terms of parts per million,
these have been converted to µgm -3 .
Table 7.8
Air Quality Standards used in the Assessment
Pollutant FEPA Standards EU Standards WHO Guidelines
Average
Period
Criterion
(µgm -3 )
Pollutant Average
Period
Criterion
(µgm -3 )
Pollutant Average
Period
Criterion
(µgm -3 )
CO 1 hr 11400 CO - - -
CO - - CO 8-hour 10000 CO 8hr 40000
CO - - CO CO 1hr 30000
NO 2 1 hr 75-113 NO 2 1 hr 200 NO 2 1 hr 200
NO 2 - - NO 2 Annual 40 NO 2 Annual 40
mean
mean
Particulates 24 hr 250 - - - - - -
- - - PM 10 24 hr 50 PM 10 24 hr 50
- - - PM 10 Annual
mean
40 PM 10 Annual
mean
20
Significance criteria
In order to determine the potential significance of the predicted impacts, two
parameters are considered:
• the Process Contribution (PC) which is the concentration of the pollutant
which would occur due to the emissions from source (ie stack emissions);
and
• the Predicted Environmental Concentration (PEC) as a percentage of the
relevant Air Quality Standard (AQS). The PEC is the addition of the
baseline concentration of the pollutant of interest and the PC.
The baseline air quality information available (Chapter 4) is not sufficiently
accurate for the determination of the PEC. Air quality measurements were
taken using handheld instruments (Multi Gas Detector and Handheld Aerosol
Monitoring) and are not derived from continuous monitoring results. On this
basis, the significance criteria normally used for this type of process which
makes reference to the PEC is not appropriate. However, the PEC is relevant
in terms of assessing cumulative impacts associated with emissions from the
neighbouring NIPP facility.
The IFC General EHS guidelines state (IFC, 2008):
“As a general rule, this Guideline suggests 25 percent of the applicable air
quality standards to allow additional, future sustainable development in the
same airshed”.
AZURA EDO IPP
7-19
DRAFT EIA REPORT