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Project Done on Behalf of
Environmental Resources Management Southern Africa (Pty) Ltd
Location and Extent of the Plant ............................................................................................................................. 1 1.2
Description of Surrounding Land Use (within 5 km radius) ..................................................................................... 2 1.3
Atmospheric Emission Licence and other Authorisations ....................................................................................... 4 1.4
2 Nature of the Process ....................................................................................................................................................... 4
Process Description (Source Draft Scoping Report for the Proposed Acetylene Gas Production Facility in 2.1
Unit Processes ........................................................................................................................................................ 5 2.3
3 Technical Information ....................................................................................................................................................... 8
Raw Materials Used and Production Rates ............................................................................................................ 8 3.1
Production Rates..................................................................................................................................................... 8 3.2
5 Impact of Enterprise on the Receiving Environment ....................................................................................................... 14
Analysis of Emissions’ Impact on Human Health .................................................................................................. 14 5.1
5.1.1 Study Methodology........................................................................................................................................... 14
Air Quality Monitoring data .................................................................................................................................... 24 5.2
Main Findings and Conclusions ............................................................................................................................ 43 5.5
Analysis of Emissions’ Impact on the Environment............................................................................................... 43 5.6
7 Current or planned air quality management interventions .............................................................................................. 45
8 Compliance and Enforcement Actions ............................................................................................................................ 46
9 Additional Information ..................................................................................................................................................... 46
10 Annexure A ..................................................................................................................................................................... 47
11 Annexure B ..................................................................................................................................................................... 48
Atmospheric Impact Report: AIR Products Acetylene Plant, Gauteng
Table 1-2: Contact details of responsible person ....................................................................................................................... 1
Table 1-3: Location and extent of the plant ................................................................................................................................ 1
Table 2-1: Listed activities at AIR Product Acetylene Plant ....................................................................................................... 5
Table 2-2: The unit processes for the AIR Products Acetylene Plant ........................................................................................ 5
Table 2-3: Location of unit processes (Source Draft Scoping Report for the Proposed Acetylene Gas Production Facility in
Table 3-1: Raw materials used ................................................................................................................................................... 8
Table 3-2: Production rates ........................................................................................................................................................ 8
Table 4-1: Point sources of atmospheric pollutant emissions at the AIR Products Acetylene Plant .......................................... 9
Table 4-2: Atmospheric pollutant emission rates for the point sources at the AIR Products Acetylene plant. ......................... 10
Table 4-3: Information sources used to estimate emission rates for point source emissions .................................................. 10
Table 4-4: Area and/or line source parameters ........................................................................................................................ 11
Table 4-5: Area source emissions ............................................................................................................................................ 12
Table 4-6: Area Source Emission Estimation Information ........................................................................................................ 13
Table 5-1: National Ambient Air Quality Standards .................................................................................................................. 18
Table 5-2: Health Screening Levels for Non-Criteria Pollutants. .............................................................................................. 18
Table 5-4: Long-term minimum, maximum and mean temperature ......................................................................................... 23
Table 5-5: Long-term average monthly rainfall (Schulze, 1986) .............................................................................................. 24
Table 6-1: Questions and Comments ...................................................................................................................................... 43
Table 8-1: AIR Products Acetylene plant compliance with MEL and NAAQS ......................................................................... 46
Atmospheric Impact Report: AIR Products Acetylene Plant, Gauteng
Report No.: 13ERM12 Rev 1.0 v
List of Figures
Figure 1-1: Location of the proposed AIR Products Acetylene plant in relation to surroundings ............................................... 3
Figure 2-1: Process Flow Diagram for a Typical Acetylene Plant (Source Draft Scoping Report for the Proposed Acetylene
Gas Production Facility in Gauteng, ERM 2014) ........................................................................................................................ 6
Figure 2-1: Boundaries of the Vaal Triangle Airshed Priority Area, as declared on 21 April 2006 ..................................... 16
Figure 5-1: Average, day-time and night-time wind roses for Vereeniging, 2010 to 2012 ....................................................... 20
Figure 5-2: Seasonal variation in wind patterns of Vereeniging, 2010 to 2012 ........................................................................ 21
Figure 5-3: Atmospheric stability of Vereeniging for the period 2010 – 2012. .......................................................................... 22
Description of Site (Where no Street Address) Stand 88 and 89 of Valley Settlements Agricultural Holdings at Daleside.
Coordinates of Approximate Centre of Operations 26.5064°S , 28.0530°E
Extent 4.4 ha
Elevation Above Sea Level 1503 m
Province Gauteng
Metropolitan/District Municipality Sedibeng District Municipality
Local Municipality Midvaal Local Municipality
Designated Priority Area Vaal Triangle Airshed Priority Area
Atmospheric Impact Report: AIR Products Acetylene Plant, Gauteng
Report No.: 13ERM12 Rev 1.0 2
Description of Surrounding Land Use (within 5 km radius) 1.3
Figure 1-1 is an aerial photograph (source: Draft Scoping Report for the Proposed Acetylene Gas Production Facility in
Gauteng, ERM 2014) indicating the location of the AIR Products Acetylene plant.
The proposed site is located in the light industrial area of Daleside, 1 km south west of the residential area of Witkopdorp.
The R59 highway is situated 600 m to the west, this highway is bordered by residential, commercial and industrial areas
running north-south next to the highway. The Pendale agricultural holdings are situated to the west of the highway. The site
is bordered by warehousing facilities and the M61 to the east, with a railway beyond that, and land use further east is mainly
agricultural and mining. The residential area of Henley-on-Klip is situated 3 km to the southeast.
Atmospheric Impact Report: AIR Products Acetylene Plant, Gauteng
Report No.: 13ERM12 Rev 1.0 3
Figure 1-1: Location of the proposed AIR Products Acetylene plant in relation to surroundings
Atmospheric Impact Report: AIR Products Acetylene Plant, Gauteng
Report No.: 13ERM12 Rev 1.0 4
Atmospheric Emission Licence and other Authorisations 1.4
The AIR Products Acetylene plant is a new plant and as such does not have an atmospheric emissions licence yet. This
report will accompany the atmospheric emissions licence application.
2 NATURE OF THE PROCESS
Process Description (Source Draft Scoping Report for the Proposed Acetylene Gas Production Facility in Gauteng, 2.1
ERM 2014)
Acetylene gas (C2H2) is a chemical compound, which has no odour or colour in its purest form. It is used amongst various
industrial sectors as a fuel or chemical building block. Air Products will produce acetylene gas from mixing calcium carbide
(CaC2) with water. This mixture results in an exothermic reaction, where acetylene gas is released. Calcium Hydroxide
(Ca(OH)2) or lime is a by-product of the reaction, this is planned to be stored on site and sold for use in other sectors (i.e.
agriculture, mining ,roads). The proposed acetylene production facility will comprise of the following key components:
turnbins;
generator vessel;
heat exchanger;
ammonia scrubber;
low pressure dryer;
compressors;
high pressure dryers; and
high pressure fillers.
Supporting infrastructure for the plant will include:
roads and paved areas;
energy supply and substation;
water supply system and storage;
chemical storage facilities;
storm water management system;
waste facilities;
administrative offices;
control rooms;
maintenance and workshop areas;
sanitation facilities; and
security facilities.
Atmospheric Impact Report: AIR Products Acetylene Plant, Gauteng
Report No.: 13ERM12 Rev 1.0 5
Listed Processes 2.2
All listed processes, as specified in the Air Quality Act, proposed to be conducted at the premises in terms of this application
are given in Table 2-1.
Table 2-1: Listed activities at AIR Product Acetylene Plant
Process Number: Listed Process Description:
6 Subcategory 6: Organic Chemical Industry
Unit Processes 2.3
The unit processes associated with the scheduled processes proposed at the premises in respect of this application are
listed in Table 2-2.
Table 2-2: The unit processes for the AIR Products Acetylene Plant
Unit Process Function of Unit Process Batch or Continuous
Process
Storage, and hoist of turnbins Storing of turnbins (raw material containers), hoisting of turnbins and
emptying into filler hoppers. Batch
Generator vessel Acetylene Production from calcium carbide and water Continuous
Heat exchanger Cooling of generated gas, cooling water supplied from cooling water
system. Continuous
Low pressure dryer Drying of low pressure acetylene gas Continuous
Ammonia scrubber Removal of ammonia from acetylene gas Continuous
Compressor Compression of acetylene gas by three stage compressor Continuous
High pressure dryer Drying of acetylene gas with molecular sieves. Continuous
Pre-inspection and high
pressure filler Product cylinder inspection, cleaning, filling and cooling. Batch
Lime Pits Temporary storage of lime by-product Continuous
Atmospheric Impact Report: AIR Products Acetylene Plant, Gauteng
Report No.: 13ERM12 Rev 1.0 6
Figure 2-1: Process Flow Diagram for a Typical Acetylene Plant (Source Draft Scoping Report for the Proposed
Acetylene Gas Production Facility in Gauteng, ERM 2014)
Atmospheric Impact Report: AIR Products Acetylene Plant, Gauteng
Report No.: 13ERM12 Rev 1.0 7
Table 2-3: Location of unit processes (Source Draft Scoping Report for the Proposed Acetylene Gas Production Facility in Gauteng, ERM 2014)
Atmospheric Impact Report: AIR Products Acetylene Plant, Gauteng
Report No.: 13ERM12 Rev 1.0 8
3 TECHNICAL INFORMATION
Raw material consumption, production rates and by-product productions rates are tabulated in Table 3-1, Table 3-2 and
Table 3-3 respectively.
Raw Materials Used and Production Rates 3.1
Table 3-1: Raw materials used
Production Rates 3.2
Table 3-2: Production rates
Table 3-3: By-products
Raw Material Type
Maximum Permitted
Consumption Rate
(Volume)
Design Consumption
Rate (Volume)
Actual Consumption
Rate (Volume) Units (quantity/period)
CaC2 24 24 tons/day
Production
Name
Maximum Production Capacity
Permitted (Volume)
Design Production
Capacity (Volume)
Actual Production
Capacity (Volume) Units (quantity/period)
Acetylene 10 10 tons/day
By-Product
Name
Maximum Production Capacity
Permitted (Volume)
Design Production
Capacity (Volume)
Actual Production
Capacity (Volume)
Units
(quantity/period)
Lime 28 28 tons/day
Atmospheric Impact Report: AIR Products Acetylene Plant, Gauteng
Report No.: 13ERM12 Rev 1.0 9
4 ATMOSPHERIC EMISSIONS
The establishment of a comprehensive emissions inventory formed the basis for the assessment of the air quality impacts from AIR Products Acetylene Plant operations on the receiving
environment.
Point Source Parameters 4.1
There are no continuous or routine point sources at the AIR Products Acetylene Plant, all point sources are expected to only be active in case of emergency. Two backup generators are plant,
one for electrical reticulation and one in case of fire. Provision is made for overpressure gas purging, but this is expected to only occur in extreme emergencies.
Table 4-1: Point sources of atmospheric pollutant emissions at the AIR Products Acetylene Plant
Not available, backup electrical generator will only be operational in case of power failure. Emergency SBG1 Oxides of Nitrogen 541.5 258 0.215
SBG1 Sulphur Dioxide 0.1 0.0408 0.0000
SBG1 Volatile Organic Compounds 264.5 126 0.105
SBG2 Particulates 302.2 144 0.12
Not available, backup generator will only be operational in case of fire. Emergency SBG2 Oxides of Nitrogen 541.5 258 0.215
SBG2 Sulphur Dioxide 0.1 0.0408 0.0000
SBG2 Volatile Organic Compounds 264.5 126 0.105
PRD1 Acetylene N/A N/A N/A
Not available, emissions will only occur as a last resort in case of overpressure. Prior to emissions occurring from these sources a number of interlocks and temperature/pressure
controls monitored with audio and visual alarms will activate and advise plant personnel that an overpressure is about to occur. The same alarms will shut down the plant to prevent emissions
from the pressure relief valves.
Emergency
PRD2 Acetylene N/A N/A N/A
Table 4-3: Information sources used to estimate emission rates for point source emissions
Point Source code
Basis for Emission Rates
SBG1 Australian NPI Emission Estimation Technique Manual for Combustion Engines, Version 3.0, June 2008 - Emissions Factors for stationary large diesel engines
SBG2 Australian NPI Emission Estimation Technique Manual for Combustion Engines, Version 3.0, June 2008 - Emissions Factors for stationary large diesel engines
PRD1 Emission from over pressure relief valves will be acetylene product with minor impurities.
PRD2 Emission from over pressure relief valves will be acetylene product with minor impurities.
Atmospheric Impact Report: AIR Products Acetylene Plant, Gauteng
Report No.: 13ERM12 Rev 1.0 11
Fugitive Emissions 4.3
Parameters and emission rates for line and area sources at the Air Products Acetylene plant are given in Table 4-4 and Table 4-5.
Table 4-4: Area and/or line source parameters
Area Source code
Source name Source Description Latitude (decimal degrees) of SW
Atmospheric Impact Report: AIR Products Acetylene Plant, Gauteng
Report No.: 13ERM12 Rev 1.0 13
Table 4-6: Area Source Emission Estimation Information
Area Source code
Basis for Emission Rates
FRK Australian NPI Emission Estimation Technique Manual for Combustion Engines, Version 3.0, June 2008 - Emissions Factors for LPG forklifts
ACT US EPA AP-42 TANKS Software, based on AP-42 Section 7.1, Organic Liquid Storage Tanks
ROAD1
Equation to calculate emissions from unpaved roads. EPA, (1996). Compilation of Air Pollution Emission Factors (AP-42) 6th Edition, Volume 1, US Environmental Protection Agency, Research Triangle Park, North Carolina
Australian NPI Emission Estimation Technique Manual for Combustion Engines, Version 3.0, June 2008 - Emissions Factors for Heavy Goods Vehicles
ROAD2
ROAD3
ROAD4
CGL European Industrial Gases Association AISBL (2008) Calculation of Air Emissions from an Acetylene Plant, IGC Doc 84/08/E
LST
Atmospheric Impact Report: AIR Products Acetylene Plant, Gauteng
Report No.: 13ERM12 Rev 1.0 14
Emergency Incidents 4.4
The AIR Products Acetylene plant is a new plant and as such no emergency incidents have been recorded.
5 IMPACT OF ENTERPRISE ON THE RECEIVING ENVIRONMENT
Analysis of Emissions’ Impact on Human Health 5.1
5.1.1 Study Methodology
5.1.1.1 Study Plan
The study methodology may conveniently be divided into a “preparatory phase” and an “execution phase”.
The preparatory phase included the flowing basic steps prior to performing the actual dispersion modelling and analyses:
1. Understand Scope of Work
2. Assign Appropriate Specialists (See Appendix A)
3. Review of legal requirements (e.g. dispersion modeling guideline) (see Section 5.1.2)
4. Decide on Dispersion Model (see Section 5.1.1.2)
The Draft Regulations Regarding Air Dispersion Modelling (Gazette No 35981 published 14 December 2012) was
referenced for the dispersion model selection.
Three levels of assessment are defined in the Draft Regulations regarding Air Dispersion Modelling:
Level 1: where worst-case air quality impacts are assessed using simpler screening models
Level 2: for assessment of air quality impacts as part of license application or amendment processes, where
impacts are the greatest within a few kilometers downwind (less than 50km)
Level 3: requires more sophisticated dispersion models (and corresponding input data, resources and model
operator expertise) in situations:
- where a detailed understanding of air quality impacts, in time and space, is required;
- where it is important to account for causality effects, calms, non-linear plume trajectories, spatial
variations in turbulent mixing, multiple source types, and chemical transformations;
- when conducting permitting and/or environmental assessment process for large industrial developments
that have considerable social, economic and environmental consequences;
- when evaluating air quality management approaches involving multi-source, multi-sector contributions
from permitted and non-permitted sources in an airshed; or,
- when assessing contaminants resulting from non-linear processes (e.g. deposition, ground-level ozone
(O3), particulate formation, visibility).
This study was considered to meet the requirements of a Level 2 assessment, and AERMOD was selected on the basis that
this Gaussian plume model is well suited to simulate dispersion where transport distances are likely to be less than 50 km.
The execution phase (i.e. dispersion modelling and analyses) firstly involves gathering specific information in relation to the
emission source(s) and site(s) to be assessed. This includes:
Precipitation represents an effective removal mechanism of atmospheric pollutants. Rainfall in the region occurs almost
exclusively in showers and thunderstorms and falls mainly in summer, from October to March. The maximum rainfall occurs
during the November-January period, while winter months are normally dry.
Monthly rainfall recorded at Vereeniging for the period July 2006 to December 2007 is presented in Figure 5-5.
Figure 5-5: Monthly rainfall (Vereeniging, Jul 2006 – Dec 2007)
The rainfall data for Vereeniging is for a short-term period and the dataset contains missing data. For a more comprehensive
overview of precipitation in the Vereeniging / Vanderbijlpark area, the long-term annual average rainfall for Vanderbijlpark
(located approximately 25 km south west of the plant site), is given in Table 5-5 (Schulze, 1986).
Atmospheric Impact Report: AIR Products Acetylene Plant, Gauteng
Report No.: 13ERM12 Rev 1.0 24
Table 5-5: Long-term average monthly rainfall (Schulze, 1986)
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Total
Average rainfall
(mm) 120 87 68 65 22 8 11 4 24 65 102 101 677
No of rain days 12.8 9.5 9.4 8.0 4.1 1.8 1.6 0.8 3.6 8.2 11.8 12.5 84.1
Air Quality Monitoring data 5.2
The Department of Environmental Affairs (DEA) operates six ambient monitoring stations in the Vaal Airshed Priority area,
four of which are situated close to the project site (Figure 5-6) and assumed to be representative of ambient air quality in the
study area. The monitoring stations from which baseline air quality information will be assessed, as well as the distance to
each and advantages and disadvantages of each (relating to this study) include:
Kliprivier, situated approximately 10 km north-northeast of the project site at the Kliprivier police station is situated
in a small industrial area, but is also downwind from the major industrial area of Alrode in Ekurhuleni, as well as
downwind from the townships of Katlehong and Thokoza. This site is expected to reflect higher ambient pollutant
concentrations - compared to the project site - due to impacts from localized sources as well as the
abovementioned industrial and residential areas. The Kliprivier station is situated a similar distance from the R59
highway as the project site.
Sharpeville, situated approximately 27 km southwest of the project site in the Sharpeville township. The
Sharpeville monitoring station is expected to reflect higher pollutant concentrations - compared to the project site -
due to domestic fuel burning activities in the township, especially during winter months. The Sharpeville station
also lies between the industrial areas of Vereeniging and Vanderbijlpark and is expected to reflect industrial
emissions from these areas.
Sebokeng, situated approximately 23 km west-southwest of the project site in the northern parts of the Sebokeng
township. This site is expected to reflect the impact of domestic fuel burning for heating and cooking in the
Sebokeng township, especially in winter months.
Three Rivers, situated approximately 17 km south-southwest of the project site. The Three Rivers monitoring
station is not expected to reflect the impact of household fuel burning (compared to the other three monitoring
stations), but will reflect the industrial impacts from Meyerton. This site is considered to be most representative of
ambient air quality in the project area with respect to background air pollution sources and ambient air quality.
Atmospheric Impact Report: AIR Products Acetylene Plant, Gauteng
Report No.: 13ERM12 Rev 1.0 25
Figure 5-6: DEA operated ambient air quality monitoring stations close to the project site
5.2.1 PM10
Measured annual average PM10 concentrations range from 50 µg/m³ at Three Rivers to 73 µg/m³ at Sharpeville. PM10
concentrations measured at all stations are in exceedance of both the current and future (applicable from 1 January 2015)
SA annual NAAQS.
Monthly PM10 concentrations show a peak in winter months, due to increased domestic fuel burning as well as reduced
natural mitigation and washout due to rainfall. Diurnal PM10 concentrations show two peaks at all stations, one at 7AM and
a larger one at 7PM. This is indicative that domestic fuel burning and to a lesser extent vehicle emissions are the main
contributing sources to PM10 emissions. The two stations closer to major thoroughfares (Kliprivier and Sharpeville) show
higher PM10 concentrations during the AM peak hours than the other two stations. All four stations show high average PM10
concentrations during the PM peak hours, due to a combination of fuel burning and traffic emissions.
Atmospheric Impact Report: AIR Products Acetylene Plant, Gauteng
Report No.: 13ERM12 Rev 1.0 26
Figure 5-7: Measured monthly average PM10 concentrations at the Vaal Airshed monitoring stations (SAAQIS, 2014)
Figure 5-8: Measured diurnal average PM10 concentrations at the Vaal Airshed monitoring stations (SAAQIS, 2014)
Atmospheric Impact Report: AIR Products Acetylene Plant, Gauteng
Report No.: 13ERM12 Rev 1.0 27
5.2.2 NO2
Measured annual average NO2 concentrations range from 23 µg/m³ at Sharpeville to 34 µg/m³ at Kliprivier. Annual Average
NO2 concentrations measured at all stations are in compliance of with the SA NAAQS.
Similar to PM10 concentrations, monthly NO2 concentrations show a peak in winter months, due to increased domestic fuel
burning as well as reduced washout due to rainfall. Diurnal NO2 concentrations also show two peaks at all stations, one at
7AM and a larger one at 7PM. This is indicative that domestic fuel burning as well as vehicle emissions are the main
contributing sources to NO2 emissions. Kliprivier station situated next to the R59 highway recorded the highest NO2
concentrations during the morning and evening peak hours. Vehicle tailpipe emissions, as well as power generation
sources were reported in the Vaal Triangle Airshed Priority Area Air Quality Management Plan (DEA, 20093) as the main
NO2 sources in the Vaal Triangle Priority Area.
Figure 5-9: Measured monthly average NO2 concentrations at the Vaal Airshed monitoring stations (SAAQIS, 2014)
3 DEA (2009) Vaal Triangle Airshed Priority Area Air Quality Management Plan, Department of Environmental Affairs and Tourism, Environmental Quality and Protection.
Atmospheric Impact Report: AIR Products Acetylene Plant, Gauteng
Report No.: 13ERM12 Rev 1.0 28
Figure 5-10: Measured diurnal average NO2 concentrations at the Vaal Airshed monitoring stations (SAAQIS, 2014)
5.2.3 SO2
Measured annual average SO2 concentrations range from 11 µg/m³ at Kliprivier to 18 µg/m³ at Sharpeville. Annual Average
SO2 concentrations measured at all stations are in compliance of with the SA NAAQS.
Monthly SO2 concentrations show a peak in winter months, due to increased domestic fuel burning as well as reduced
washout due to rainfall. Diurnal SO2 concentrations increased during the day to reach a maximum at around 2PM, indicative
of industrial (and power generation) SO2 sources as the major contributing sources of SO2. Sharpeville station, situated
between the Vereeniging and Vanderbijlpark industrial areas, recorded the highest average SO2 concentrations during 2013,
with the Kliprivier station recording the lowest average SO2 concentrations.
Atmospheric Impact Report: AIR Products Acetylene Plant, Gauteng
Report No.: 13ERM12 Rev 1.0 29
Figure 5-11: Measured monthly average SO2 concentrations at the Vaal Airshed monitoring stations (SAAQIS, 2014)
Figure 5-12: Measured diurnal average SO2 concentrations at the Vaal Airshed monitoring stations (SAAQIS, 2014)
Atmospheric Impact Report: AIR Products Acetylene Plant, Gauteng
Report No.: 13ERM12 Rev 1.0 30
5.2.4 Benzene
The four closest monitoring stations do not measure VOC concentrations and a SA NAAQS has also not been established
for VOCs. It was therefore decided to calculate cumulative VOC impacts with measured benzene concentrations which are
measured at the four closest monitoring stations, and to assess cumulative concentrations against the SA annual NAAQS
for benzene (5 µg/m³).
Measured annual average benzene concentrations range from 1.5 µg/m³ at Kliprivier to 2.5 µg/m³ at Sebokeng. Annual
average benzene concentrations measured at all stations are in compliance of with the SA NAAQS.
Similar to PM10 and NO2 concentrations, monthly benzene concentrations show a peak in winter months, and diurnal
benzene concentrations also show two peaks at all stations, one at 7AM and a larger one at 7PM. This is indicative that
vehicle emissions are the main contributing sources to benzene emissions. The highest concentrations of benzene were
measured at the Sebokeng and Sharpeville stations.
Figure 5-13: Measured monthly average benzene concentrations at the Vaal Airshed monitoring stations (SAAQIS,
2014)
Atmospheric Impact Report: AIR Products Acetylene Plant, Gauteng
Report No.: 13ERM12 Rev 1.0 31
Figure 5-14: Measured diurnal average benzene concentrations at the Vaal Airshed monitoring stations (SAAQIS,
2014)
Atmospheric Impact Report: AIR Products Acetylene Plant, Gauteng
Report No.: 13ERM12 Rev 1.0 32
Dispersion Modelling Results 5.3
5.3.1 Particulate (PM10) emissions
The identified emission sources of PM10 at the AIR Products Acetylene Plant include:
Construction activities during the construction phase
Vehicle entrainment from product and raw material trucks on the paved on-site ring road.
Vehicle tailpipe exhaust from forklifts as well as product and raw material trucks.
Backup generator exhaust
5.3.1.1 Predicted PM10 and PM2.5 ambient concentrations
Reported baseline ambient PM10 concentrations exceed the SA NAAQS at the four closest monitoring stations, and is
assumed to also exceed the SA NAAQS at the project site. Predicted PM10 concentrations are therefore presented as
incremental impacts (Figure 5-17 and Figure 5-19) as well as the percentage increase from baseline conditions. Measured
annual average PM10 concentrations at the four monitoring stations range between 50 µg/m³ and 73 µg/m³, therefore no
cumulative impacts are presented as baseline concentrations are assumed to exceed the SA NAAQS for all areas.
Construction Phase Impacts
Annual Average PM10 concentrations during the construction phase (Figure 5-15) are predicted to increase (Figure 5-16)
with up to 40 µg/m³ on the AIR Products Acetylene Plant property and immediately to the south and south-east. Due to the
nature of construction activities during the construction phase; impacts are expected to be intermittent and of limited
duration.
Figure 5-15: Predicted annual average PM10 concentrations during the construction phase.
Atmospheric Impact Report: AIR Products Acetylene Plant, Gauteng
Report No.: 13ERM12 Rev 1.0 33
Figure 5-16: Predicted increase in annual average PM10 concentrations from baseline conditions during the
construction phase.
Operational Phase Impacts
Incremental annual average PM10 concentrations during the operational phase are predicted to be very low, less than 4
µg/m³ just outside the property boundary.
An increase from baseline PM10 concentrations (Figure 5-18) of approximately 15% due to the AIR Product Acetylene Plant
operations were predicted to be limited to the Plant property, with PM10 concentrations predicted to increase less than 10%
from baseline concentrations directly to the south-east of the plant site.
The possibility exists for the SA daily PM10 NAAQS to be exceeded directly outside the property boundary should the
backup generators be used continuously (more than 24 hours) for more than four days per year.
Atmospheric Impact Report: AIR Products Acetylene Plant, Gauteng
Report No.: 13ERM12 Rev 1.0 34
Figure 5-17: Predicted annual average PM10 concentrations during the operational phase.
Figure 5-18: Predicted increase in annual average PM10 concentrations from baseline conditions during the
operational phase.
Atmospheric Impact Report: AIR Products Acetylene Plant, Gauteng
Report No.: 13ERM12 Rev 1.0 35
Figure 5-19: Predicted highest daily incremental PM10 concentrations during the operational phase.
5.3.2 Nitrogen dioxide emissions
The identified emission sources of NO2 at the AIR Products Acetylene Plant include:
Vehicle tailpipe exhaust from forklifts as well as product and raw material trucks.
Backup generator exhaust.
5.3.2.1 Predicted NO2 ambient concentrations
Reported baseline ambient NO2 concentrations comply with the SA annual NAAQS at the four closest monitoring stations,
ranging between 23µg/m³ at Sharpeville and 34µg/m³ at Kliprivier. The baseline NO2 concentrations at the project site were
assumed to be represented by an average of the four monitoring station, 25 µg/m³. Predicted NO2 concentrations are
presented as incremental annual (Figure 5-20) and hourly (Figure 5-21) impacts, cumulative annual average impacts (Figure
5-22) as well as the increase from baseline conditions (Figure 5-23).
Incremental annual average NOx concentrations during the operational phase are predicted to be very low, with predicted
NO2 concentrations under 5µg/m³ outside the plant boundary.
Cumulative annual average and highest hourly NO2 concentrations during the operational phase were predicted to comply
with the SA NAAQS for the entire study area. The SA hourly NO2 NAAQS could possibly be exceeded outside the site
boundary if the standby generators are utilised for more than 88 hours per year.
Atmospheric Impact Report: AIR Products Acetylene Plant, Gauteng
Report No.: 13ERM12 Rev 1.0 36
Figure 5-20: Predicted incremental annual average NO2 concentrations during the operational phase.
Figure 5-21: Predicted incremental highest hourly NO2 concentrations during the operational phase.
Atmospheric Impact Report: AIR Products Acetylene Plant, Gauteng
Report No.: 13ERM12 Rev 1.0 37
Figure 5-22: Predicted cumulative annual average NO2 concentrations during the operational phase.
Figure 5-23: Predicted increase in annual average NO2 concentrations from baseline conditions during the
construction phase.
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Report No.: 13ERM12 Rev 1.0 38
5.3.3 Sulphur dioxide emissions
The identified emission sources of SO2 at the AIR Products Acetylene Plant include:
Vehicle tailpipe exhaust from forklifts as well as product and raw material trucks.
Backup generator exhaust.
5.3.3.1 Predicted SO2 ambient concentrations
SO2 sources at the AIR Products Acetylene plant were expected to result in insignificant increases in ambient SO2
concentrations (0.1% increase in annual average SO2 concentrations). Predicted cumulative ambient SO2 comply with the
SA NAAQS for all three averaging periods.
5.3.4 Acetone emissions
The identified emission sources of acetone at the AIR Products Acetylene Plant include:
Working and standing losses from the acetone storage tank.
Fugitive acetone emissions from cylinder cleaning and filling operations.
5.3.4.1 Predicted ambient acetone concentrations
Impacts on ambient acetone concentrations were predicted to be negligible, with annual average concentrations predicted to
be 12 µg/m³ at most, less than 0.1% of the lowest health guideline (the US ATSDR RfC of 30 900 µg/m³).
5.3.5 Phosphine emissions
The identified emission sources of acetylene (and phosphine impurities) at the AIR Products Acetylene Plant include:
Fugitive emissions from the charging of the generator.