Environmental Impact Assessment Course Project

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1.0 INTRODUCTION

With the booming of the economy, dramatic developments occur in most countries

around the world, especially in some developing countries such as Brazil. The typical

phenomenon is the expansions of cities, which leads to increasing number of construction

projects to be operated each year. These projects represent the fast developments but also cause

environmental impacts, especially in the atmospheric quality within urban areas.

1.1 Executive Summary

The purpose of this project is to determine the distributions of major air pollutants

released from a typical construction site via studying a project located in Brazil and understand

the atmospheric impacts of the fast urban expansion. Two main studies are used as the references,

which include an essay Identification and Characterization of Particulate Matter Concentration

at Construction Jobsites by Araujo, Costa, and Moraes (2014) and a report Building Assemblies:

Construction Energy & Emissions conducted by University of British Columbia (1993).

Overall, six major atmospheric pollutants, namely Total Suspended Particulate (TSP),

PM10, PM2.5, Carbon Monoxide, Nitrogen Dioxide and Sulfur Dioxide, are analyzed in this

report. The method used in the analysis is the Gaussian Plume, the emission place is assumed to

be a point source at the center of the construction site, and the distribution of each pollutant is

summarized in a Table and a corresponding diagram. As can be seen in the session of analysis,

based on the standards for air pollutants conducted by Brazilian relevant authorities and World

Health Organization (WHO), the emissions of nitrogen dioxide, carbon monoxide and sulfur

dioxide are of highest significance, but for other 3 pollutants, their influences that should be

concerned do not exceed 100 meters along the centerlines of corresponding Gaussian Plumes

from the source.

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In order to understand the impacts on human health, Air Quality Health Index conducted

by Canadian environmental authority is also utilized in the analysis. According to the analysis

results, the risky zone is within the area 100 meters from the emission source.

After the analysis, the mitigating measures are provided. In terms of the mitigations,

controlling the emissions of carbon monoxide, nitrogen dioxide and sulfur dioxide is of

importance since their significant influences. Specifically, since the limitation of resources, the

efficiencies of controlling methods are assumed.

1.2 Problem Statement

As explained in the Session 1.0, with the dramatic growth of the global economy, an

increasing number of construction projects are introduced each year, which leads to the

environmental problems. In the urban area, the emissions of gas pollutants and particulate

matters is of significance; especially for the developing countries, this issue is much more drastic.

Air pollution can cause both acute and chronic effects on public health, impacting on a

large number of different systems and organs. These impacts range from minor upper respiratory

irritation to chronic heart and respiratory disease, lung cancer, acute respiratory infections in

children and chronic bronchitis in adults, aggravating pre-existing heart and lung disease, or

asthmatic attacks. Additionally, short and long-term exposures have also been linked with

reduced life expectancy and premature mortality [1].

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1.3 Methodology

This session introduces two methods used in the analysis, namely Gaussian Plume

Method and Air Quality Health Index Method.

1.3.1 Gaussian Plume Method

As introduced above, the gases in analysis can be divided into two categories, namely gas

pollutants and particulate matters. First, the particulate matters include PM 2.5, PM 10, and total

suspended particulates (TSP). The relevant data are obtained from an essay Identification and

Characterization of Particulate Matter Concentration at Construction Jobsites (Araujo, Costa,

and Moraes, 2014). Second, in terms of the gas pollutants, namely sulphur dioxide, carbon

monoxide, and nitrogen dioxide, the emission rates are obtained from a report Building

Assemblies: Construction Energy & Emissions conducted by University of British Columbia in

1993.

In terms of the analysis method, Gaussian Plume is used to establish the diffusion model.

In the Gaussian Model, it assumes that the air pollutants dispersion has a Gaussian distribution,

which is a normal probability distribution [2]. At present, Gaussian models are usually used to

predict the dispersion of non-continuous air pollution plumes. The basic Gaussian Plume

equation is concluded as:

𝑐 =𝑄

2𝜋𝜎!𝜎!𝑢𝑒! !!!!!!

! !!! !

!!!!

Where: 𝐾! = 0.5𝜎!!

𝑢𝑥

𝐾! = 0.5𝜎!!𝑢𝑥

𝑡 =𝑥𝑢

𝜎! ,𝜎! = ℎ𝑜𝑟𝑖𝑧𝑜𝑛𝑡𝑎𝑙 𝑎𝑛𝑑 𝑣𝑒𝑟𝑡𝑖𝑐𝑎𝑙 𝑑𝑖𝑠𝑝𝑒𝑟𝑠𝑖𝑜𝑛 𝑐𝑜𝑒𝑓𝑓𝑖𝑐𝑖𝑒𝑛𝑠 (𝑚𝑒𝑡𝑒𝑟)

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Horizontal dispersion coefficient 𝜎! can be determined by the diagram shown in Figure 1,

and Figure 2 demonstrates the relationship between the downwind distance and vertical

dispersion coefficient 𝜎!. [3]

Specifically, since the construction site is close to the residential district with low-rise

buildings, only the air near the ground will be analyzed, which means “z-H” in the formula

should be 0.

Figure 1: Horizontal Dispersion Coefficient 𝝈𝒚 as a Function of Downwind Distance from the Source for Various Stability Categories.

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Figure 2: Vertical Dispersion Coefficient 𝝈𝒛as a Function of Downwind Distance from the Source for Various Stability Categories

In terms of the stability categories, Table 1 introduces the relevant information.

Table 1: Key to Stability Categories [4]

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1.3.2 Air Quality Health Index

The Air Quality Health Index (AQHI) is a public information tool used in Canada to

prevent people’s health from the negative effects of air pollution on a daily basis. Basically, it is

measured by the formula:

𝐴𝑄𝐻𝐼 =10010.4× 𝑒!.!!!"#$×!!! − 1 + 𝑒!.!!!"#$×!!"! − 1 + 𝑒!.!!!"#$×!!"!.! − 1

Where:

𝑐!! = Concentration of ozone, ppb

𝑐!"! = Concentration of NO2, ppb

𝑐!"!.! = Concentration of PM2.5, 𝜇𝑔 𝑚!

After obtaining the value of Air Quality Health Index, the influence level can be

determined by Table 2.

Table 2: Canadian Air Quality Health Index Reference Table [5]

Specifically, in this report, only the points along the centerline of the Gaussian Plume are

analyzed by AQHI because the values along the centerline should be the most critical.

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1.4 Construction Site Introduction

The studied construction site is located in Salvador, Bahia, Brazil, (latitude 12°57’46”

south, longitude 38°24’32” west) at an altitude of 34 m. The proposed project contains 8

residential towers, each with 16 floors, totaling 464 housing units. The total construction area is

32,780 m2. [6] Figure 3 introduces the construction location obtained by Google Earth.

Specifically, since there is no explanation of the dimensions of construction site, the area is

assumed to be a square, and the length of each side is 181 m.

The construction site is located in a low-rise residential district with the appearance of

flora and fauna, including a lake. Within an area of 100 m, there is no primary pollution source

such as other construction sites, industries, major highways and airports. [7]

Figure 3: Construction Site (via Google Earth)

A typical series of construction activities for reinforced concrete structures can be

categorized into 3 major phases, namely the earthwork, superstructure, and finishing. First, the

earthwork includes manual excavation, meso structure, razing of auger piles foundation,

vehicular traffic on the soil, land transportation, and truck traffic at the construction site. Second,

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in terms of the superstructure, it refers to the activities namely execution of reinforced concrete

components; lift masonry, mortar execution, and masonry shaft. Third, the finishing contains

finishing the external and internal mortar, grouting masonry façade, ceramic coating, crystallized

waterproofing, countertops marble/granite, lining plasterboard plates, and sanding.

These activities can produce significant amounts of air pollutants and impact the

atmospheric qualities.

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2.0 CASE STUDY

This session introduces the air quality standards posed by Brazilian relevant authorities

and World Health Organization, the means of data collections, and the analysis of atmospheric

pollutants by Gaussian Plume Method.

2.1 Air Quality Standards

In Brazil, the standardized pollutants are TSP, smoke, sulfur dioxide (SO2), inhalable

particles, carbon monoxide (CO), and nitrogen dioxide (NO2). The Brazilian National

Environmental Council (CONAMA) Resolution Number 3 published on August 1990 indicates

that the primary standards should be adopted if relevant area classes are not established [8].

Table 3: Brazilian National Air Quality Standards [9]

Pollutant Averaging Time Primary Standards Secondary Standards TSP 24 h 240 𝜇𝑔 𝑚! 150 𝜇𝑔 𝑚!

Geometric Annual Average 80 𝜇𝑔 𝑚! 60 𝜇𝑔 𝑚! PM10 24 h 150 𝜇𝑔 𝑚!

Arithmetic Annual Average 50 𝜇𝑔 𝑚! SO2 24 h 365 𝜇𝑔 𝑚! 100 𝜇𝑔 𝑚!

Arithmetic Annual Average 80 𝜇𝑔 𝑚! 40 𝜇𝑔 𝑚! CO 1 h 40,000 𝜇𝑔 𝑚!

8 h 10,000 𝜇𝑔 𝑚! NO2 1 h 320 𝜇𝑔 𝑚! 190 𝜇𝑔 𝑚! Arithmetic Annual Average 100 𝜇𝑔 𝑚!

Since there is no standard of PM2.5 in Brazil, the standard posted by World Health

Organization (WHO) will be used in this report. Thus, the PM2.5 concentration should be 25

µμg m! within 24 hours, and 10 µμg m! within a year.

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2.2 Data

This session explains the means of data collections, the specific numbers will be used for

further analysis in Session 2.3, and the situation of the meteorology.

2.2.1 Particulate matters

As introduced previously, the particulate matters include PM 2.5, PM 10, and Total

Suspended Particulates (TSP). According to the essay Identification and Characterization of

Particulate Matter Concentration at Construction Jobsites, the concentrations of these three

pollutants were obtained by the MiniVols Equipment because of it portability (the appearance is

shown in Figure 4). It was installed during three major construction phases, namely earthworks,

superstructure, and finishing; for each phase, the detection period was 10 days.

Figure 4: MiniVols [10]

In order to decrease the influence from the existed particulate matters in the air, there

were two sets of equipment were installed. One set was placed at the construction site entrance

for measuring the concentrations of PMs entering the construction site, and the other set was

installed at the end of the construction site for measuring the PMs exiting the construction site.

The measuring operations were performed at the same periods. The measuring period is

introduced in Table 4.

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Table 4: Measuring Schedule [11]

Shifts Schedule Period Length Day 7 am to 3 pm 8 hours Night 5 pm to 3 pm 22 hours After adjusting the measurements by subtracting the PMs existing the air, the PMs

produced during the construction are shown in Table 5 [12].

Table 5: Descriptive Statistics of PM Concentrations in 𝝁𝒈 𝒎𝟑 for Three Construction Phases

As can be seen in Table 5, all the maximum average concentrations of three studied

particulate matters occurred during the Phase 2 that is superstructure. Results are 483.12 µμg m!

for TSP, 213.94 µμg m! for PM10, and 77.85 µμg m! for PM2.5. These results will be discussed

in later sessions.

2.2.2 Gas Pollutants

In terms of the gas pollutants, according to the report Building Assemblies: Construction

Energy & Emissions conducted by University of British Columbia in 1993, the maximum

emissions of three major gas pollutants are introduced in Table 6.

Table 6: Maximum Emissions of Three Major Gas pollutants [13]

Gas pollutants Maximum Emissions CO 402.21 g/s NOx 83.32 g/s SO2 17.75 g/s

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In the further study, the concentration of nitrogen gas pollutants (NOx) is regarded as the

nitrogen dioxide (NO2).

2.2.3 Meteorology

During measuring the concentrations of particulate matters, the meteorological data were

also recorded and concluded in the essay Identification and Characterization of Particulate

Matter Concentration at Construction Jobsites (Araujo, Costa, and Moraes, 2014). Table 7

shows the relevant data.

Table 7: Meteorological Data during Measuring [14]

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According to Table 7, the average wind speed is 1.43 m/s, and the wind direction is

assumed to be the same in the further analysis. In addition, as can be seen in the column of

Pluviometry, most data are 0.0, which indicates that the incoming solar radiation should be

considered as “strong” in the analysis.

According to Table 1, during the daytime, the stability category should be A. No analysis

regarding of the night time will be posed. Based on Figure 1 and Figure 2, Gaussian Plume

Models can be formed for each air pollutants.

2.3 Analysis by Gaussian Plume Method

This session explains the detailed process of using Gaussian Plume to determine the

distributions of six air pollutants. In addition, relevant discussions for each pollutant are also

provided.

2.3.1 TSP

As can be seen in Session 2.2.1, the measurement of the TSP concentration is

483.12µμg m!. In order to use the formula 𝑐 = !!!!!!!!

𝑒! !!

!!!!! !!! !

!!!! , it is assumed that the

measurement was processed at the point in the centerline of Gaussian Plume with a distance of

100m from the source; in addition, the pollution source is assumed as a point source. Specifically,

these assumptions are also applied to the analysis for other atmospheric pollutants.

First, since the distance is 100m (0.1 km), according to Figure 1and 2, 𝜎! and 𝜎! are

determined as 30m and 15m, and the point is in the centerline of the Gaussian Plume:

𝑐 =𝑄

2𝜋𝜎!𝜎!𝑢

483.12 µμg m! =𝑄

2𝜋 30𝑚 15𝑚 (1.43 𝑚/𝑠)

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∴ 𝑄 = 1,953,365 µμg s

Secondly, find the values of 𝜎! and 𝜎! for different distances. In the analysis, 12

distances are chosen, namely 0.1 km, 0.2 km, 0.3 km, 0.4 km, 0.5 km, 0.6 km, 0.7 km, 0.8 km,

0.9 km, 1 km, 2 km, and 3 km. These distances are also discussed for other pollutants. Table 8

concludes the 𝜎! and 𝜎! values.

Table 8: 𝝈𝒚 and 𝝈𝒛 Values for 12 Chosen Distances

Distance (km) 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 2 3

𝝈𝒚 30 50 65 80 100 120 150 170 200 205 400 500 𝝈𝒛 15 30 40 60 80 140 190 280 390 470 1800 4000

Thirdly, determine the distribution of TSP in different distance. For each distance, except

for the point in centerline, 10 points in different ditances from the centerline, namely -50m, -40m,

-30, -20m, -10m, 10m, 20m, 30m, 40m, and 50m, are analyzed. Table 9 summarized the results.

Table 9: TSP Distribution Summary

TSP Distributions, 𝛍𝐠 𝐦𝟑

Distance, km 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 2 3

Dis

tanc

e fr

om th

e C

ente

rlin

e, m

-50 120 88 62 37 24 12 7 4 3 2 0 0 -40 199 105 69 40 25 12 7 4 3 2 0 0 -30 293 121 75 42 26 13 7 4 3 2 0 0 -20 387 134 80 44 27 13 8 5 3 2 0 0 -10 457 142 83 45 27 13 8 5 3 2 0 0 0 483 145 84 45 27 13 8 5 3 2 0 0 10 457 142 83 45 27 13 8 5 3 2 0 0 20 387 134 80 44 27 13 8 5 3 2 0 0 30 293 121 75 42 26 13 7 4 3 2 0 0 40 199 105 69 40 25 12 7 4 3 2 0 0 50 120 88 62 37 24 12 7 4 3 2 0 0

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According to the Brazilian national standard for Total Suspended Particulate (TSP)

indicated in Table 3, within 24 hours, the primary standard is 240 µμg m!, and the secondary is

150 µμg m!. Since the construction site is within a residential district as shown in Figure 3, the

secondary standard is dominant. As can be seen in Table 9, the influence should be concerned

can exist up to 200 meters; at the point of 100 meters, the concerned area is more than 40 meters

from the centerline. Figure 5 shows the distribution of the TSP concentrations in various

distances from the source and the centerline. The red curve represents the standard used in the

analysis.

Figure 5: TSP Distribution

-‐50

-‐40

-‐30

-‐20

-‐10

0

10

20

30

40

50

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 2 3

Distan

ce from

the Ce

nterlin

e, m

Distance from the Source, km

400-‐500

300-‐400

200-‐300

100-‐200

0-‐100

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2.3.2 PM10

In the same manner as described for the analysis of TSP, the emission rate of PM10 is

estimated at:

𝑄 = 𝑐!.! !"2𝜋𝜎!𝜎!𝑢

𝑄!"!" = 213.94 2𝜋 30𝑚 15𝑚 (1.43 𝑚/𝑠) = 865008.572 𝜇𝑔 𝑠

Thus, the PM10 distribution can be calculated and relevant results are shown in Table 10.

Table 10: PM10 Distribution Summary

PM10 Distributions, 𝛍𝐠 𝐦𝟑

Distance, km 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 2 3

Dis

tanc

e fr

om th

e C

ente

rlin

e, m

-50 53 39 28 16 11 5 3 2 1 1 0 0 -40 88 47 31 18 11 5 3 2 1 1 0 0 -30 130 54 33 19 12 6 3 2 1 1 0 0 -20 171 59 35 19 12 6 3 2 1 1 0 0 -10 202 63 37 20 12 6 3 2 1 1 0 0 0 214 64 37 20 12 6 3 2 1 1 0 0 10 202 63 37 20 12 6 3 2 1 1 0 0 20 171 59 35 19 12 6 3 2 1 1 0 0 30 130 54 33 19 12 6 3 2 1 1 0 0 40 88 47 31 18 11 5 3 2 1 1 0 0 50 53 39 28 16 11 5 3 2 1 1 0 0

According to the standard of PM10 shown in Table 3, within 24 hours, both of the

primary and secondary standards are 150 µμg m!. Thus, the influence should be concerned

cannot reach 200 meters from the source in the centerline; for the point that is 100m from the

source in the centerline of the Gaussian Plume, the distance of the affected area exceeds 20

meters.

Based on the results, the PM10 distribution vs. the distance from the source and distance

from the Gaussian Plume centerline is concluded in Figure 6.

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Figure 6: PM10 Distribution

2.3.3 PM2.5

In the same analysis method, the emission rate of PM2.5 is estimated at 314765.436

µμg m!. Thus, the pollutant distribution can be summarized in Table 11.

Table 10: PM2.5 Distribution Summary

PM2.5 Distributions, 𝛍𝐠 𝐦𝟑

Distance, km 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 2 3

Dis

tanc

e fr

om th

e C

ente

rlin

e, m

-50 19 14 10 6 4 2 1 1 0 0 0 0 -40 32 17 11 6 4 2 1 1 0 0 0 0 -30 47 20 12 7 4 2 1 1 0 0 0 0 -20 62 22 13 7 4 2 1 1 0 0 0 0 -10 74 23 13 7 4 2 1 1 0 0 0 0 0 78 23 13 7 4 2 1 1 0 0 0 0 10 74 23 13 7 4 2 1 1 0 0 0 0 20 62 22 13 7 4 2 1 1 0 0 0 0 30 47 20 12 7 4 2 1 1 0 0 0 0 40 32 17 11 6 4 2 1 1 0 0 0 0 50 0 0 0 0 1 1 1 0 0 0 0 0

-‐50

-‐40

-‐30

-‐20

-‐10

0

10

20

30

40

50

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 2 3

Distan

ce from

the Ce

nterlin

e, m


200-‐250

150-‐200

100-‐150

50-‐100

0-‐50

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Since there is no standard of PM2.5 in Brazil, the standard set by World Health

Organization (WHO), which is 25 µμg m!, will be used. As can be seen in Table 10, the

concerned distance from the source along the centerline cannot reach 200 meters. At the point

100 meters from the source, the influenced distance off the line is more than 40 meters. The

results of PM2.5 distribution is shown in Figure 7.

Figure 7: PM2.5 Distribution

2.3.4 Carbon Monoxide (CO)

According to Table 6, the emission rate of carbon monoxide (CO) is estimated at

402.214g s, so the distribution can be determined and is shown in Table 11. Due to Table 3, the

standard for 8 hours is 10,000𝜇𝑔 𝑚!; thus, the influenced area is within up to 300 meters, which

exceeds the size of the construction site, then some mitigations should be applied. The

distribution is also concluded in Figure 8.

-‐50

-‐40

-‐30

-‐20

-‐10

0

10

20

30

40

50

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 2 3

Distan

ce from

the Ce

nterlin

e, m


60-‐80

40-‐60

20-‐40

0-‐20

19

Table 11: Carbon Monoxide Distribution Summary

CO Distributions,

𝛍𝐠 𝐦𝟑

Distance, km

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 2 3

Dis

tanc

e fr

om th

e C

ente

rlin

e, m

-50 24805 18101 12808 7671 4938 2443 1486 901 556 451 62 22 -40 40897 21671 14247 8230 5165 2521 1516 915 563 456 62 22 -30 60337 24927 15478 8693 5349 2583 1540 926 567 460 62 22 -20 79656 27549 16421 9039 5485 2628 1557 934 571 462 62 22 -10 94103 29253 17015 9254 5568 2655 1567 939 573 464 62 22 0 99478 29844 17217 9326 5596 2665 1571 940 574 465 62 22 10 94103 29253 17015 9254 5568 2655 1567 939 573 464 62 22 20 79656 27549 16421 9039 5485 2628 1557 934 571 462 62 22 30 60337 24927 15478 8693 5349 2583 1540 926 567 460 62 22 40 40897 21671 14247 8230 5165 2521 1516 915 563 456 62 22 50 24805 18101 12808 7671 4938 2443 1486 901 556 451 62 22

Figure 8: CO Distribution

-‐50

-‐40

-‐30

-‐20

-‐10

0

10

20

30

40

50

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 2 3

Distan

ce from

the Ce

nterlin

e, m


80000-‐100000

60000-‐80000

40000-‐60000

20000-‐40000

0-‐20000

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2.3.5 Nitrogen Dioxide (NO2)

According to Table 6, the emission rate is 83.32 g/s; therefore, the distribution of

Nitrogen dioxide can be concluded in Table 12.

Table 12: Nitrogen dioxide Distribution Summary

NO2 Distributions, 𝛍𝐠 𝐦𝟑

Distance, km 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 2 3

Dis

tanc

e fr

om th

e C

ente

rlin

e, m

-50 5138 3750 2653 1589 1023 506 308 187 115 93 13 5 -40 8472 4489 2951 1705 1070 522 314 189 117 94 13 5 -30 12499 5164 3206 1801 1108 535 319 192 118 95 13 5 -20 16501 5707 3402 1872 1136 544 322 193 118 96 13 5 -10 19494 6060 3525 1917 1153 550 325 194 119 96 13 5 0 20607 6182 3567 1932 1159 552 325 195 119 96 13 5 10 19494 6060 3525 1917 1153 550 325 194 119 96 13 5 20 16501 5707 3402 1872 1136 544 322 193 118 96 13 5 30 12499 5164 3206 1801 1108 535 319 192 118 95 13 5 40 8472 4489 2951 1705 1070 522 314 189 117 94 13 5 50 5138 3750 2653 1589 1023 506 308 187 115 93 13 5

As can be seen in Table 12, since the standard shown in Table 3 is 190 𝜇𝑔 𝑚!, the

influence of nitrogen dioxide is of significance. Along the centerline of the Gaussian Plume, the

influence can reach the distance more than 800 meters from the source. For the points

100/200/300/400/500/600/700 meters from the source in the centerline, the length of offline

points beyond the standard is more than 50 meters. In terms of the point 800 meters from the

source, the length is more than 30 meters. Thus, some corresponding mitigations should be

applied.

In addition, the distribution is also concluded in a diagram shown in Figure 9.

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Figure 9: Nitrogen Carbon Distribution

2.3.6 Sulfur Dioxide (SO2)

Finally, for the sulfur dioxide (SO2), according to Table 6, the emission rate is 17.75 g/s.

Thus, the distribution can be calculated and is summarized in Table 13.

Table 13: Sulfur Dioxide Distribution Summary

SO2 Distributions,

𝛍𝐠 𝐦𝟑

Distance, km

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 2 3

Dis

tanc

e fr

om th

e C

ente

rlin

e, m

-50 1095 799 565 339 218 108 66 40 25 20 3 1 -40 1805 956 629 363 228 111 67 40 25 20 3 1 -30 2663 1100 683 384 236 114 68 41 25 20 3 1 -20 3515 1216 725 399 242 116 69 41 25 20 3 1 -10 4153 1291 751 408 246 117 69 41 25 20 3 1 0 4390 1317 760 412 247 118 69 42 25 21 3 1 10 4153 1291 751 408 246 117 69 41 25 20 3 1 20 3515 1216 725 399 242 116 69 41 25 20 3 1 30 2663 1100 683 384 236 114 68 41 25 20 3 1 40 1805 956 629 363 228 111 67 40 25 20 3 1 50 1095 799 565 339 218 108 66 40 25 20 3 1

-‐50

-‐40

-‐30

-‐20

-‐10

0

10

20

30

40

50

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 2 3

Distan

ce from

the Ce

nterlin

e, m


20000-‐25000

15000-‐20000

10000-‐15000

5000-‐10000

0-‐5000

22

According to Table 3, the Brazilian national secondary standard of Sulfur Dioxide is 100

𝜇𝑔 𝑚! within 24 hours, so the influence can be more than 600 meters from the source along the

centerline of Gaussian Plume. For the points off the centerline, the distance between the last

offline point beyond the standard and the centerline is more than 50 meters. Thus, some

corresponding mitigations should be posed. The distribution is also shown in Figure 10.

Figure 10: Sulfur Dioxide Distribution

-‐50

-‐40

-‐30

-‐20

-‐10

0

10

20

30

40

50

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 2 3

Distan

ce from

the Ce

nterlin

e, m


300-‐400

200-‐300

100-‐200

0-‐100

23

2.4 Analysis by Air Quality Health Index

According to the analysis by the Gaussian Plume, the concentrations of Nitrogen Dioxide

and PM2.5 along the centerline of the Gaussian Plume are determined. In terms of the ozone,

Table 14 shows the ozone level measured in a construction site.

Table 14: Ozone Produced During Construction [15]

The 0.12ppm is chosen as the estimated concentration of ozone in a typical construction

site. Use the same way explained in Session 2.3.1 to determine the emission rate of ozone, then

determine the distribution along the Gaussian Plume centerline. The concentrations of three

major elements in the AQHI formula are shown in Table 15.

Table 15: Concentrations of Ozone, Nitrogen Dioxide and PM2.5 along Centerline

Distance, km 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 2 3

Ozone, ppb 120 36 21 11 7 3 2 1 1 1 0 0

NO2, ppb 1096 329 190 103 62 29 18 10 6 5 1 0

PM2.5, 𝝁𝒈 𝒎𝟑 78 23 13 7 4 2 1 1 0 0 0 0

24

Specifically, since the original unit of ozone is ppm, the conversion 1 ppm = 1 ppb is

used for its calculation. Similarly, the unit of NO2 discussed in Session 2.3.5, so the conversion 1

ppb of NO2 = 1.88 𝜇𝑔 𝑚! of NO2 is used. For example, the concentration of NO2 at the

centerline point 100 m from the source is estimated at 2061𝜇𝑔 𝑚!, then it should be conversed

to !"#$!.!!

= 1096 ppb.

Based on the values shown in Table 15, the Air Quality Health Index and corresponding

health risk level can be determined and it is summarized in Table 16 and Figure 11.

Table 16: Air Quality Health Index

Distance, km 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 2 3

AQHI 16.38 3.48 1.90 0.99 0.59 0.27 0.16 0.09 0.06 0.05 0.00 0 Health Risk

Very High Low Low Low Low Low Low Low Low Low Low Low

Figure 11: AQHI vs. Distance

As can be seen in Figure 11, the AQHI decreases dramatically with the distance from the

pollution increases. The most critical area is within 100 meters from the construction site.

-‐2.00

0.00

2.00

4.00

6.00

8.00

10.00

12.00

14.00

16.00

18.00

0 0.5 1 1.5 2 2.5 3 3.5

AQHI

Distance, km

Very High Risk

High Risk

Moderate Risk

Low Risk

25

3.0 MITIGATIONS

As explained in Session 2.3, the emissions of three gas pollutants, namely carbon

monoxide, nitrogen dioxide and sulfur dioxide, should be mitigated. Due to the assumption

posed in Session 1.4, the construction site is a square and its length is 181 meters. Thus, the

purpose of the mitigations is to control the concentrations of these gas pollutants can satisfy the

atmospheric standards beyond 181 meters from the emission point. In order to facilitate the

engineering process, the centerline point 200 meters from the emission point should satisfy the

standards. Table 17 concludes the estimated concentrations of three pollutants and corresponding

standards.

Table 17: Estimated Pollutants Concentrations at the Edge of the Construction Site vs. Standards

Emission Rate, g/s Concentrations, 𝜇𝑔 𝑚! Standards, 𝜇𝑔 𝑚! CO 402.21 g/s 29844 10000 NO2 83.32 g/s 6182 190 SO2 17.75 g/s 1317 100

In terms of the carbon monoxide, 𝜎! and 𝜎! are 50m and 30m at 0.2km from the emission

point; if c is 10000𝜇𝑔 𝑚!, then:

𝑐 =𝑄

2𝜋𝜎!𝜎!𝑢𝑒! !!!!!!

! !!! !

!!!!

10000 =𝑄

2𝜋 50 30 1.43

𝑄 = 132,700,920 𝜇𝑔 𝑠 = 132.7 𝑔/𝑠

So the reduction rate should be:

𝑅𝑒𝑑𝑢𝑐𝑡𝑖𝑜𝑛 𝑅𝑎𝑡𝑖𝑜!" =402.21− 132.70

402.21 = 67%

In the same manner, the objective reduction rates for these pollutants can be calculated

and summarized in Table 18

26

Table 18: Objectives of Reduction Rates

Objective Reduction Rates CO 67% NO2 97% SO2 93%

In order to achieve these objectives, here are some specific measures based on the

guideline Air Pollution Control at Construction Sites posed by Swiss Agency for the

Environment, Forests and Landscape (SAEFL) (2004).

Table 19: Mitigating Measures [16]

Construction Activities Mitigations

Ther

mal

and

Che

mic

al W

ork

Proc

esse

s

Restrict the thermal preparation of tar-based material and coating at building sites Use the asphalt or bitumen that has low emission rates of air pollutants Use bitumen emulsions instead of bitumen solutions Apply appropriate measures for binding material to lower the processing temperature In order to abate the welding emissions, it is necessary to capture, extract (e.g. spot suction) and filter the emitted fumes. When treat the surface or glue/seal the gaps, choose eco-friendly products Deploy low emission explosives (e.g. formulated as emulsion, slurry or water gel)

Stip

ulat

ions

for

Mac

hine

s And

Eq

uipm

ent

Use low-emission equipment (e.g. powered with electrical motors) Equip and maintain combustion-engine powered tools/machines based on the manufacturers’ specifications Use low-sulfur fuels (sulfur content <50ppm) for machines and equipment to power the diesel engines Diesel-powered machines and equipment must be equipped with particle trap systems (PTS) or other equivalently effective emission curtailment traps

Con

stru

ctio

n Fu

lfillm

ent For scheduling, the contractor must submit the pertinent list before work

begins, and regularly update the list in order to ensure punctual availability of the appropriate machines and equipment (a sample of pertinent list is shown in Appendix A) Train the workers about the origin, dispersal, impact and abatement of airborne pollutants in order to promote the relevant awareness

27

4.0 CONCLUSION

The purpose of this project is to determine distributions of air pollutants around a typical

construction site and provide corresponding mitigating measures. There are six air pollutants

being discussed in the report, namely Total Suspended Particulate (TSP), PM10, PM2.5, Carbon

Monoxide, Nitrogen Dioxide and Sulfur Dioxide. In the analysis, two methods are used, which

includes Gaussian Plume and Air Quality Health Index.

The construction site for the study is located in Salvador, Bahia, Brazil, (latitude

12°57’46” south, longitude 38°24’32” west) at an altitude of 34 m. As described in Session 1.4,

the construction site is assumed as a square and its length is approximately 200m. The emission

rates are estimated in the basis of the data obtained from an essay Identification and

Characterization of Particulate Matter Concentration at Construction Jobsites by Araujo, Costa,

and Moraes (2014) and a report Building Assemblies: Construction Energy & Emissions

conducted by University of British Columbia (1993).

In terms of results of Gaussian Plume method, carbon monoxide, nitrogen dioxide and

sulfur dioxide are three gas pollutants that should be controlled. For other three pollutants, their

influences should be concerned cannot reach 200m from the emission source, which is within the

construction site, so it is unnecessary to control the emission rates of these three pollutants.

When it comes to Air Quality Health Index (AQHI), the obvious risky area is within the

construction site, which indicates the residential districts around the construction site are not

effectively offended.

For mitigations, in order to decrease the constructions of carbon monoxide, nitrogen

dioxide and sulfur to the levels satisfying corresponding Brazilian Standards outside of the

construction area, some measures are provided in Session 4.0 in the basis of a guideline Air

28

Pollution Control at Construction Sites posed by Swiss Agency for the Environment, Forests and

Landscape (SAEFL) (2004). Basically, the mitigating measures are divided into three categories

corresponding to three construction activities producing these three gas pollutants. Since the

limits of the resources, the decreases of emission rates caused by each measure cannot be

determined, only the objectives of reduction rates are calculated.

29

REFERENCE

[1] ‘Spare The Air: Health Effects of Air Pollution’, Air Quality Information for the Sacramento

Region. [Online]. Available: http://www.sparetheair.com/health.cfm?page=healthoverall.

[Accessed: 10-Apr-2015].

[2] M. R. Beychok, Fundamentals of stack gas dispersion, 4th ed. Irvine, CA: Milton R.

Beychok, 1994.

[3] N. De Nevers, Air Pollution Control Engineering. William C Brown Pub, 2000.

[4] N. De Nevers, Air Pollution Control Engineering. William C Brown Pub, 2000.

[5] ‘Air Quality Health Index - Home - Air - Environment Canada’, Environment Canada.

[Online]. Available: https://ec.gc.ca/cas-aqhi/default.asp?lang=En. [Accessed: 10-Apr-2015].

[6] I. P. S. Araujo, D. B. Costa, and R. J. B. de Moraes, ‘Identification and Characterization of

Particulate Matter Concentrations at Construction Jobsites’, Nov. 2014.





[9] ‘Brazil: Air Quality Standards’, Tansportpolicy.net, 07-May-2014. [Online]. Available:

http://transportpolicy.net/index.php?title=Brazil:_Air_Quality_Standards. [Accessed: 03-Apr-

2015].



30





[13] The Environmental Research Group, Building Assemblies: Construction Energy &

Emissions. Vancouver: University of British Columbia, 1993.



[15] Hazard Evaluation and Technical Assistance Branch of NIOSH, ‘Ozone Exposure at a

Construction Site’, Apr. 1999.

[16] A. Staubli and R. Kropf, Air Pollution Control at Construction Sites. Berne: Swiss Agency

for the Environment, Forests and Landscape, 2004.

Documents

Environmental Impact Assessment Course Project