Indoor Plants

Are indoor plants adapted to get rid formaldehyde, Sipin, Elly Lorreta one of the noxious wastes commonly found at home nowadays

1.0 Introduction

I did further research and found out that indoor air pollution phenomenon has urged the NASA (National Aeronautics and Space Administration) scientists to study the functions of plants to provide clean indoor air. NASA has become the pioneer towards this research and recently has been widened by many other associations like the Wolverton Environmental Services, Inc. endorsed by the Plants for Clean Air Council in Mitchellville, Maryland[1]. Research done by NASA has found out that there are certain plants that have the function to purify the air in a building[2]. They detoxify the existing toxins and pollutants which originate from the things used in daily activities nowadays; fabrics, detergents and also furniture. These pollutants can be classified into three common indoor pollutants according to the list of indoor contaminant that are currently present. There are benzene, formaldehyde and trichloroethylene. (TCE)[3]

Plants use the concept of transpiration to work onto this problem[4]. As the vaporized chemical enters the stomatal opening on the leaves of the indoor plants, they are either broken down directly or be sent downwards; down to the root system of the plants.[5] The presence of colonies of microbes at the root system breaks down various kinds of unhealthy compounds; in this case the indoor pollutants, and absorbs them as their source of food[6]. As for the mechanism of transpiration to remove the pollutant, water vapour that is liberated by the leaves of the plants will mix with the air in the atmosphere. Convection of air leads to the movement of the atmospheric air that is contaminated with the vaporized chemical downwards to the base of the plants.

I chose 6 types of plants to be experimented by one fixed type of pollutant; formaldehyde. It is normally used in the production of grocery bags, facial tissues, waxed paper, waxed paper[7] and produced by tobacco products, gas cookers and open fireplaces.[8] In the experiment, this chemical is predicted to be absorbed by each plant. Plant that absorbs the chemical the most would be the efficient plant to be included in places mentioned before.

2.0 Aim

To study the effect of plants transpiration towards the acidity and mass of formaldehyde in a transparent chamber.

3.0 Planning and method development

Firstly, a chamber must be set up to place plants chosen. A pot of selected plant is placed into each chamber. 6 types of plants were chosen, therefore 6 chambers must be created. To make sure that air, sunlight and water could be continuously supplied, I decided that the chamber must be transparent, and there are holes to let air enters. The material that I chose is transparent plastic so that holes can be poked, the wall of the chambers can be flipped to water the plants everyday and plants get sufficient sunlight.

I selected formaldehyde as the pollutant to the plants. In each of the chamber, I included formalin of the same amount in a beaker and let it evaporate in the chamber. As formalin CH2O, is a reducing agent[9], therefore it has the ability to release its hydrogen.[10] The more hydrogen ions present in it, the greater the strength of the acid. When evaporation of formalin happens continuously, there will be less in quantity of hydrogen atoms in the aqueous solution. Thus, the acidity of formaldehyde could decrease through evaporation; pH of the formalin increases. So, the pH of the formalin is ought to be checked for every interval of two days. Because concept of evaporation is used, it is for sure the volume of the formalin will reduce. The most effective method to measure this is by getting the mass decrease. I took the reading of the mass of formalin for every interval of two days. I decided to take note on the external condition of all the plants so that analysis on that can be done to find its relativity with formalin.

4.0 Hypothesis

My prediction is that indoor plants have the ability to get rid of formaldehyde, one of the noxious wastes commonly found at home nowadays by absorbing the chemicals through their microscopic openings perforated on their leaves; the stomata[11]. As the chemical evaporates, the molecules of the chemical are absorbed by the plants by gaining entrance through the stomata. These plants transport the absorbed chemical to their root system along the xylem of the plants to be broken down by the microbes present at the roots.[12] As formalin acts as a reducing agent, release of hydrogen could occur. Through evaporation of formalin, there will be less hydrogen atoms could remain in the aqueous solution. Thus, it is possible for the decrease in mass and increase in the pH of the formalin to occur when indoor plants are available.

5.0 Methodology

5.1 Variables

a) Independent:

* Types of plants chosen to be experimented

There are variety types of plants chosen in order to know whether the hypothesis could be accepted. They are Boston fern (Nephrolepis exaltata “Bostoniensis”), Janet Craig(Dracaena deremensis), Florist's mum(Chrysanthemum morifolium), Kimberly queen fern (Nephrolepis obliterata), Snake plant or mother-in-law's tongue (Sansevieria trifasciata 'Laurentii'), Himalayan Balsam (Impatiens glandulifera) altogether. Himalayan Balsam (Impatiens glandulifera) acts as the control of the experiment to show its less in efficiency to absorb the toxin. Some plants have no ability to absorb the chosen toxin as good as in some indoor plants.

b) Dependent:

* The rate of absorption of formaldehyde

The rate of absorption of formaldehyde is taken as the decrease in mass of formalin over time. This is documented for every interval of two days. Other than that, the acidity of formaldehyde in each chamber is also noted. This is done by using pH paper and pH meter to indicate the change in pH. The pH of the formalin in the chamber is recorded to see the pattern of change in acidity.

c) Fixed:

* The type of toxin chosen; formaldehyde

Liquid formalin is selected to be one of the fixed variables in this experiment so that the analysis of the change in acidity can be done easily. More than one type of pollutant will promote confusion while conducting the experiment as the characteristic of one pollutant differ from one to another. Formalin is the aqueous state of the chemical formaldehyde and the concentration of the liquid formalin is 100%. I made the volume and the concentration of liquid formalin the same in every small beaker included in every transparent chamber. It is important to do so because the pH of the chemical and its mass are to be checked every 2 days throughout the duration of the experiment. The initial pH of the chemical is 3.510 while the initial volume of the chemical is 10 ± 0.5 ml making its mass to be 10.19 ± 0.01 g

* The estimated size of the plants chosen

The chosen plants are of the same size. There is no specific measurement for the plants sizes so therefore, the size is depending on the experimenter's justification by fixing the number of leaves present in every plant chosen. This is due to the mechanism of the absorption of the chemical formalin happens through the microscopic opening present on the leaves; the stomata. It is therefore can be predicted that more tiny opening present on the leaves, the more effective would the rate of absorption be. I decided that the total number of leaves is approximately 15-20 leaves depending on the how broad the surface of the leaves is.

* The size of the pyramidal transparent chamber

The size of the pyramidal transparent chamber is to be made constant by using the same size and number of transparent plastic bags. The size of the plastic bags is 23cm x 38cm and they are cut into same shapes to fit it with the skeleton of the chamber. The base of the chamber is triangular in shape and constant with the area of ½ (50cm x 50cm).

5.2 Materials

MATERIALS

QUANTITY

JUSTIFICATION

Formalin

120ml

Formalin acts as the toxin in the experiment.

Tap Water

5 litres

This is used to water the plants everyday for 2 weeks duration.

5.3 Apparatus

APPARATUS

QUANTITY

JUSTIFICATION

Boston fern

(N. exaltata)

1 pot

These are the plants chosen to determine their effectiveness to absorb the formalin.

Janet Craig

(D. deremensis)

1 pot

Florist's mum

(C. morifolium)

1 pot

Kimberly queen fern

(N. obliterata)

1 pot

Snake plant

(S. trifasciata)

1 pot

Himalayan Balsam

(I. glandulifera)

1 pot

pH paper

1 box

To check the acidity of formalin every 2 days.

pH meter

1

To determine the pH of the formalin every 2 days.

Disposable plastic cups

24

To be the base of the pyramidal transparent chamber.

Plastic and bamboo chopsticks

54

To be the poles of the pyramidal transparent chamber.

Electronic balance

1

To measure the decrease in mass of the liquid formalin for every 2 days.

50ml beaker

6

To place the liquid formalin in each chamber.

50ml measuring cylinder

1

To measure the amount of formalin in each 50ml beaker.

Transparent plastics for packaging

(23cm x 38cm)

1 pack

To become the cover of the chamber.

5.4 Methodology to prepare a chamber for the plant

A chamber has to be invented to place the chosen plants, considering the needs of those plants to get sufficient sunlight, air and water. I chose transparent plastics and attach them together to create a pyramidal transparent chamber. Holes were also poked to allow air move into the chamber.
I included nine chopsticks to be the poles of chamber. A pole comprised of 3 combined chopsticks. To increase its stability, I poked a hole onto the bases of three disposable plastic cups and inserted the chopsticks into the holes.

5.5 Methodology to determine the change in acidity of formaldehyde

After the chamber was set up, I prepared the solution of the toxin chosen; formalin.in a 50ml beaker. 10 ± 0.5 ml of the chemical in each beaker was measured using 50ml measuring cylinder.
6 transparent chambers were set up to place 6 types of plants which were the Boston fern (N. exaltata), Janet Craig (D. deremensis), Florist's mum (C. morifolium), Kimberly queen fern (N. obliterata), Snake plant (S. trifasciata), and Himalayan Balsam (I. glandulifera). All the 6 chambers contained different pots of plants and 10ml of formalin in a 50ml beaker.
At intervals of 2 days, the mass of the formalin was recorded. The procedure to get the mass of formalin in each chamber was as follows;

* Take the reading of the mass of 50ml beaker before filling in the formalin by using electronic balance. Repeat the steps 3 times in order to get the average reading.

* Weigh the 50ml beaker containing formalin by using electronic balance. Repeat the procedure 3 times in order to get the average reading.

The reading of the mass of the formalin + 50ml beaker at intervals of 2 days was recorded. The mass of the formalin was determined by subtracting the average value of the mass of formalin + 50ml beaker with the average mass of the 50ml beaker.
The pH was again checked by using pH paper and also pH meter for 2 weeks. The change in colour of the pH paper and the reading of the pH meter were noted and documented.
Each of the plants in the chamber was watered once a day using tap water. The amount of tap water must was 20ml per watering and watering time was at 10.30 a.m and 4.00 p.m. every day.
Condition for each of the plants was observed for interval time of 2 days.
All of results were recorded in a table.

5.5.1 Precaution

1. Beware while handling formalin because it is a dangerous chemical. Since a high concentration of formaldehyde will be used in the experiment, [13]it may cause burning sensation to the eyes, nose and lungs. Thus it could result in allergic reaction because of formalin.

2. Be cautious when building the pyramidal transparent chamber especially when dealing with the bamboo sticks. Avoid any sharp splinter of the bamboo stick from piercing into the skin.

6.0 Data collection

TABLE 1: THE pH of FORMALIN IN EACH TRANSPARENT CHAMBER WITH DIFFERENT PLANTS IN 14 DAYS

Transparent chamber containing plants

Value of Ph of formalin in each transparent chamber according to number of days

2 days

4 days

6 days

8 days

10 days

12 days

14 days

Boston fern (N. exaltata “Bostoniensis”)

3.510

3.550

3.570

4.020

4.130

4.260

4.310

Janet Craig (D. deremensis)

3.510

3.570

3.580

4.020

4.070

4.210

4.430

Florist's mum (C. morifolium)

3.510

3.570

3.590

4.120

4.200

4.320

4.620

Kimberly queen fern (N. obliterate)

3.510

3.510

3.520

4.010

4.030

4.050

4.110

Snake plant (S. trifasciata 'Laurentii')

3.510

3.370

3.360

4.030

4.030

4.030

4.030

Himalayan Balsam (I. glandulifera)

3.510

3.370

3.370

3.350

3.350

3.350

3.350

Note: The pH of formalin in each beaker was checked at the same interval to ensure that none of the formalin being absorbed more by their respective plants. The time that they were checked was at a range of 4.00 p.m. until 4.45 p.m.

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Are indoor plants adapted to get rid formaldehyde, Sipin, Elly Lorreta one of the noxious wastes commonly found at home 002348-019 nowadays

TABLE 2: MASS OF FORMALIN + 50ml BEAKER IN EACH CHAMBER CONTAINING DIFFERENT PLANTS IN 14 DAYS

Transparent chamber containing plants

Mass of formalin + 50ml beaker in each transparent chamber ± 0.01g

2 days

4 days

6 days

1st

2nd

3rd

1st

2nd

3rd

1st

2nd

3rd

Boston fern (N. exaltata)

46.950

46.960

46.960

46.530

46.540

46.550

46.230

46.220

46.220

Janet Craig (D. deremensis)

46.910

46.910

46.910

46.520

46.520

46.510

46.310

46.310

46.310

Florist's mum (C. morifolium)

46.940

46.940

46.950

46.610

46.600

46.610

46.350

46.340

46.350

Kimberly queen fern (N. obliterata)

46.970

46.970

46.970

46.620

46.620

46.640

46.430

46.410

46.410

Snake plant (S. trifasciata)

46.920

46.910

46.910

46.620

46.630

46.610

46.420

46.410

46.430

Himalayan Balsam(I. glandulifera)

46.940

46.940

46.930

46.780

46.790

46.790

46.720

46.710

46.720

Note: The mass of the formalin was measured at intervals of 2 days and it was at a range of time from 4.00 p.m. until 4.45 p.m.

10

Are indoor plants adapted to get rid formaldehyde, Sipin, Elly Lorreta

one of the noxious wastes commonly found at home 002348-019

nowadays

Transparent chamber containing plants

Mass of formalin + 50ml beaker in each transparent chamber ± 0.01g

8 days

10 days

12 days

14 days

1st

2nd

3rd

1st

2nd

3rd

1st

2nd

3rd

1st

2nd

3rd

Boston fern (N. exaltata)

46.010

46.030

46.040

45.480

45.480

45.470

45.210

45.220

45.220

44.950

44.960

44.980

Janet Craig (D. deremensis)

45.520

45.530

45.530

45.030

45.030

45.020

44.960

44.960

44.920

44.580

44.590

44.580

Florist's mum (C. morifolium)

45.550

45.550

45.560

45.220

45.210

45.220

44.940

44.940

44.950

44.130

44.130

44.140

Kimberly queen fern (N. obliterata)

45.500

45.510

45.510

45.320

45.350

45.350

44.980

44.980

44.990

44.220

44.230

44.230

Snake plant (S. trifasciata)

45.890

45.900

45.890

45.530

45.530

45.530

45.140

45.140

45.120

44.970

44.960

44.970

Himalayan Balsam(I. glandulifera)

46.680

46.680

46.680

46.340

46.340

46.320

46.290

46.290

47.300

46.250

46.240

46.250

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Are indoor plants adapted to get rid formaldehyde, Sipin, Elly Lorreta one of the noxious wastes commonly found at home 002348-019 nowadays

Transparent chamber

containing plants

Change in colour of pH paper

2 days

4 days

6 days

8 days

10 days

12 days

14 days

Boston fern (N. exaltata)

Green leaves

Green leaves

Green leaves

Green leaves

Green leaves

Green leaves

Green leaves

Janet Craig (D. deremensis)

Green leaves

Green leaves

Green leaves

Green leaves

Green leaves

Yellow leaves

Brown Leaves

Florist's mum (C.morifolium)

Green leaves

Green leaves

Green leaves

Wilted flowers

Wilted flowers

Yellow leaves

Yellow leaves

K. queen fern (N. obliterata)

Green leaves

Green leaves

Green leaves

Green leaves

Yellow leaves

Yellow leaves

Yellow leaves

Snake plant (S. trifasciata)

Green leaves

Green leaves

Green leaves

Green leaves

Green leaves

Green leaves

Green leaves

H. Balsam (I. glandulifera)

Green leaves

Green leaves

Yellow leaves

Yellow leaves

Yellow leaves

Brown leaves

Brown leaves

TABLE 3: DAILY CONDITION OF PLANTS IN THE TRANSPARENT CHAMBERS IN 14 DAYS

Note: Only Florist's mum (C.morifolium) in this experiment has flowers. When the edges of the leaves becoming brown or yellow, it is indicated as having brown leaves or yellow leaves. The font in italic form indicates the adverse change onto the plants.

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Are indoor plants adapted to get rid formaldehyde, Sipin, Elly Lorreta one of the noxious wastes commonly found at home 002348-019 nowadays

TABLE 4: CHANGE IN COLOUR OF pH PAPER WHEN pH OF FORMALIN FOR A DURATION OF TWO WEEKS

Transparent chamber

containing plants

Change in colour of pH paper

2 days

4 days

6 days

8 days

10 days

12 days

14 days

Boston fern (N. exaltata )

Light orange

Light orange

Light orange

Light orange

Light orange

Light orange

Light orange

Janet Craig (D. deremensis)

Light orange

Light orange

Light orange

Light orange

Light orange

Light orange

Light orange

Florist's mum (C. morifolium)

Light orange

Light orange

Light orange

Light orange

Light orange

Light orange

Light orange

K. queen fern (N. obliterata)

Light orange

Light orange

Light orange

Light orange

Light orange

Light orange

Light orange

Snake plant (S. trifasciata)

Light orange

Light orange

Light orange

Light orange

Light orange

Light orange

Light orange

H. Balsam (I. glandulifera)

Light orange

Light orange

Light orange

Light orange

Light orange

Light orange

Light orange

Note: The original colour of the pH paper is light yellow in colour

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Are indoor plants adapted to get rid formaldehyde, Sipin, Elly Lorreta one of the noxious wastes commonly found at home 002348-019 nowadays

7.0 Data processing

7.1 pH difference of formalin

I discover that there are some changes in pH of the formalin in the transparent chamber. The following table shows the total difference in the final and the initial pH of the formalin in each transparent chamber.

TABLE 5: DIFFERENCE IN pH OF FORMALIN IN EACH TRANSPARENT CHAMBER

Transparent chamber containing plants

Final pH

Initial pH

Difference in pH

Boston fern (N. exaltata)

4.310

3.510

0.800

Janet Craig (D. deremensis)

4.430

3.510

0.920

Florist's mum (C. morifolium)

4.620

3.510

1.110

Kimberly queen fern (N. obliterate)

4.110

3.510

0.600

Snake plant (S. trifasciata)

4.030

3.510

0.520

Himalayan Balsam (I. glandulifera)

3.350

3.510

0.160

Note: The method to calculate the pH of formalin in chamber containing Himalayan Balsam is inverted, since the pH value decreased so that negative value can be ignored.

7.2 Data for mean mass of formalin

The following table shows the average mass of formalin + 50ml beaker for 14 days

TABLE 6: AVERAGE MASS OF FORMALIN + 50ml BEAKER IN EACH CHAMBER CONTAINING DIFFERENT PLANTS IN 14 DAYS

Transparent chamber containing plants

Average mass of formalin+50ml beaker in each chamber ± 0.01g

Day 2

Day 4

Day 6

Day 8

Day 10

Day 12

Day 14

Boston fern (N. exaltata)

46.960

46.540

46.220

46.030

45.480

45.220

44.960

Janet Craig (D. deremensis)

46.910

46.520

46.310

45.530

45.030

44.950

44.580

Florist's mum (C. morifolium)

46.940

46.610

46.350

45.550

45.220

44.540

44.130

K. queen fern (N. obliterate)

46.970

46.630

46.420

45.510

45.340

44.980

44.240

Snake plant (S. trifasciata)

46.910

46.620

46.420

45.890

45.330

45.130

44.970

H. Balsam (I. glandulifera

46.940

46.790

46.720

46.680

46.330

46.290

44.250

Note: The average masses were obtained by totaling up the three mass values in three trials, and divide it into three.

7.3 Graph for the decreasing mass of formalin

In order to get a graph of decrease in mass of formalin from day 0 to day 14, the real mass of formalin is required. Therefore, the table of mass of formalin for a duration of 14 days is made as follows.

The formulation to calculate the mass of formalin in each beaker would be;

Mass of formalin= [(Average mass of formalin+50ml beaker)-

Average mass of 50ml beaker]

TABLE 7: MASS OF FORMALIN IN EVERY 50ml BEAKER CONTAINED IN TRANSPARENT CHAMBER WITH DIFFERENT TYPES OF PLANTS

Transparent chamber containing plants

Mass of formalin ± 0.01g

[(Average mass of formalin+50ml beaker) - Average mass of 50ml beaker]

Day 2

Day 4

Day 6

Day 8

Day 10

Day 12

Day 14

Boston fern (N. exaltata)

10.170

9.750

9.430

9.240

8.690

8.430

8.170

Janet Craig (D. deremensis)

10.120

9.730

9.520

8.740

8.240

8.160

7.790

Florist's mum (C. morifolium)

10.150

9.820

9.560

8.760

8.430

8.150

7.340

K. queen fern (N. obliterate)

10.180

9.840

9.630

8.760

8.430

8.150

7.450

Snake plant (S. trifasciata)

10.120

9.830

9.630

9.100

8.540

8.340

8.180

H. Balsam (I. glandulifera

10.150

10.000

9.930

9.890

9.540

9.500

9.460

Note: The average mass of one 50ml beaker is 36.79 ± 0.1g. This value was used to calculate the mass above.

The bar graph of decrease in mass of the formalin against number of days for each beaker containing formalin in every transparent chamber is as follows;

graph 1: decrease in mass of the formalin against number of days for each beaker containing formalin in every transparent chamber

Note: The graph shows quite obvious inclination of mass of formalin in all chambers except for the H. Balsam (I. glandulifera)

7.4 Mass and percentage of formalin absorbed

The initial average mass of the 10ml formalin in the 50ml beaker is 46.980 ± 0.01g and the average mass of the 50ml beaker alone is 36.790 ± 0.01g making the mass of the 10.000 ± 0.1 ml formalin poured in to be 10.190 ± 0.01g. From the data, there is a decreasing pattern of the mass of the formalin in the 50ml beaker. The percentage of decrease in mass of the 10.000 ± 0.1 ml formalin in 14 days of time in respective transparent chamber of plants can be determined. Before that, the mass of formalin absorbed in all the 6 transparent chambers must be d up. Calculation is as follows;

TABLE 8: MASS OF FORMALIN ABSORBED BY PLANTS IN EACH CHAMBER

Name of plants in each chamber

Mass of formalin absorbed

[Initial mass (10.190)- Mass on the14th day] ± 0.01g

Boston fern (N. exaltata)

2.020

Janet Craig (D. deremensis)

2.400

Florist's mum (C. morifolium)

2.850

Kimberly queen fern (N. obliterate)

2.740

Snake plant (S. trifasciata)

2.010

H. Balsam (I. glandulifera

0.730

Note: The mass of formalin absorbed by plants in each chamber is referring to the decrease in mass of formalin throughout the 12 days duration.

It is possible to calculate the percentage of decrease in mass of formalin absorbed by using the formulation below. The table below shows the percentage in respective 50ml beaker of formalin in all 6 chambers;

Percentage of decrease in = Mass of formalin absorbed x 100%

mass of formalin Initial mass of formalin

TABLE 9: PERCENTAGE DECREASE IN MASS OF FORMALIN IN THE 50ml BEAKER IN RESPECTIVE TRANSPARENT CHAMBER

Transparent chamber containing plants

Percentage of decrease in mass of formalin absorbed

Percentage of decrease in mass of formalin (%)

Boston fern (N. exaltata)

2.020/10.190 x 100

19.820

Janet Craig (D. deremensis)

2.400/10.190 x 100

23.550

Florist's mum (C. morifolium)

2.850/10.190 x 100

27.970

Kimberly queen fern (N. obliterate)

2.740/10.190 x 100

26.890

Snake plant (S. trifasciata)

2.010/10.190 x 100

19.730

Himalayan Balsam (I. glandulifera)

0.730/10.190 x 100

7.160

Note: The comparison of decrease in mass of formalin in beaker is based on the initial mass of formalin in the beaker.

The greater the percentage of decrease in masses of formalin, the better the quality of air in the chamber, the better formalin absorber would the plant be. The following diagram shows the ascending order of the quality of plant as formalin absorber.

Himalayan Balsam (I. glandulifera)

Snake plant (S. trifasciata)

Boston fern (N. exaltata)

Janet Craig (D. deremensis)

Kimberly queen fern (N. obliterate)

Florist's mum (C. morifolium)

7.5 Calculation for mean, standard deviation and T-test

TABLE 10 : TABLE OF MEAN AND STANDARD DEVIATION FOR EVERY PLANTS CHOSEN

Mass

± 0.01g

 

Plants

Boston fern (N. exaltata)

Janet Craig (D. deremensis)

Florist's mum (C. morifolium)

Kimberly queen fern (N. obliterata)

Snake plant (S. trifasciata)

Himalayan Balsam (I. glandulifera)

1st trial

2.000

2.330

2.810

2.000

1.950

0.690

2nd trial

2.000

2.320

2.810

2.740

1.950

0.700

3rd trial

1.980

2.330

2.810

2.740

1.940

0.680

Mean

1.993

2.327

2.810

2.493

1.947

0.690

Std. Dev

0.009

0.005

0.000

0.349

0.005

0.008

Note: The mean was determined by getting the difference of mass of formalin between 14th day with the 0 day; initial mass.

The formulation to calculate t-test is as follows;

t-value =_____difference in mean___

difference of standard error

TABLE 11: TABLE OF T-VALUE FOR THE COMPARISON OF MASS DECREASE MEAN BETWEEN BOSTON FERN (N. exaltata) AND JANET CRAIG (D. deremensis)

Mass

± 0.01g

Plants

Boston fern (N. exaltata)

Janet Craig (D. deremensis)

Difference between Boston fern and Janet Craig

1 trial

2.000

2.330

0.330

2 trial

2.000

2.320

0.320

3 trial

1.980

2.330

0.340

Mean

1.993

2.327

0.330

Std. Dev

0.009

0.005

0.008

Std. Error

1.151

1.343

0.191

Degree of freedom

2.000

Critical value at 5% level

4.300

t-value

1.728

Null Hypothesis: There is no significance difference for decrease in mass between Boston fern (N. exaltata) and Janet Craig (D. deremensis)

| t | = 1.728 < 4.300

Thus, null hypothesis is rejected. The mean difference is not significant

TABLE 12: TABLE OF T-VALUE FOR THE COMPARISON OF MASS DECREASE MEAN BETWEEN BOSTON FERN (N. exaltata) AND FLORIST'S MUM (C. morifolium)

Null Hypothesis: There is no significance difference for decrease in mass between Boston fern (N. exaltata) and Florist's mum (C. morifolium)

Mass

± 0.01g

Plants

Boston fern (N. exaltata)

Florist's mum (C. morifolium)

Difference between Boston fern and Florist's mum

1 trial

2.000

2.810

0.810

2 trial

2.000

2.810

0.810

3 trial

1.980

2.810

0.810

Mean

1.993

2.810

0.810

Std. Dev

0.009

0.000

0.000

Std. Error

1.151

1.622

0.468

Degree of freedom

2.000

Critical value at 5% level

4.300

t-value

1.731

| t | = 1.731 < 4.300

Thus, null hypothesis is rejected. The mean difference is not significant.

TABLE 13: TABLE OF T-VALUE FOR THE COMPARISON OF MEAN BETWEEN BOSTON FERN (N. exaltata) AND KIMBERLY QUEEN FERN (N. obliterata)

Null Hypothesis: There is no significance difference for decrease in mass between Boston fern (N. exaltata) and Kimberly queen fern (N. obliterata)

Mass

± 0.01g

Plants

Boston fern (N. exaltata)

Kimberly queen fern (N. obliterata)

Difference between Boston fern and Kimberly queen fern

1 trial

2.000

2.000

0.810

2 trial

2.000

2.740

0.810

3 trial

1.980

2.740

0.810

Mean

1.993

2.493

0.810

Std. Dev

0.009

0.349

0.000

Std. Error

1.151

1.439

0.468

Degree of freedom

2.000

Critical value at 5% level

4.300

t-value

1.730

| t | = 1.730 < 4.300

Thus, null hypothesis is rejected. The mean difference is not significant.

TABLE 14: TABLE OF T-VALUE FOR THE COMPARISON OF MEAN BETWEEN BOSTON FERN (N. exaltata) AND SNAKE PLANT (S. trifasciata)

Null Hypothesis: There is no significance difference for decrease in mass between Boston fern (N. exaltata) and Snake plant (S. trifasciata)

Mass

± 0.01g

Plants

Boston fern (N. exaltata)

Snake plant (S. trifasciata)

Difference between Boston fern and Snake plant

1 trial

2.000

1.950

0.050

2 trial

2.000

1.950

0.050

3 trial

1.980

1.940

0.040

Mean

1.993

1.950

0.050

Std. Dev

0.009

0.005

0.005

Std. Error

1.151

1.126

0.029

Degree of freedom

2.000

Critical value at 5% level

4.300

t-value

1.724

| t | = 1.724 < 4.300

Thus, null hypothesis is rejected. The mean difference is not significant.

TABLE 15: TABLE OF T-VALUE FOR THE COMPARISON OF MEAN BETWEEN BOSTON FERN (N. exaltata) AND HIMALAYAN BALSAM

(I. glandulifera)

Null Hypothesis: There is no significance difference for decrease in mass between Boston fern (N. exaltata) and Himalayan Balsam(I. glandulifera)

Mass

± 0.01g

Plants

Boston fern (N. exaltata)

Himalayan Balsam(I. glandulifera)

Difference between Boston fern and Himalayan Balsam

1 trial

2.000

0.690

1.310

2 trial

2.000

0.700

1.300

3 trial

1.980

0.680

1.300

Mean

1.993

0.690

1.303

Std. Dev

0.009

0.008

0.005

Std. Error

1.151

0.398

0.752

Degree of freedom

2.000

Critical value at 5% level

4.300

t-value

1.733

| t | = 1.733 < 4.300

Thus, null hypothesis is rejected. The mean difference is not significant.

TABLE 16: TABLE OF T-VALUE FOR THE COMPARISON OF MEAN BETWEEN JANET CRAIG (D. deremensis) AND FLORIST'S MUM (C. morifolium)

Null Hypothesis: There is no significance difference for decrease in mass between

Janet Craig (D. deremensis) and Florist's mum (C. morifolium)

Mass

± 0.01g

Plants

Janet Craig (D. deremensis)

Florist's mum (C. morifolium)

Difference between Janet Craig and Florist's mum

1 trial

2.330

2.810

0.480

2 trial

2.320

2.810

0.490

3 trial

2.330

2.810

0.480

Mean

2.327

2.810

0.483

Std. Dev

0.005

0.000

0.005

Std. Error

1.343

1.622

0.279

Degree of freedom

2.000

Critical value at 5% level

4.300

t-value

1.732

| t | = 1.732 < 4.300

Thus, null hypothesis is rejected. The mean difference is not significant.

TABLE 17: TABLE OF T-VALUE FOR THE COMPARISON OF MEAN BETWEEN JANET CRAIG (D. deremensis) AND KIMBERLY QUEEN FERN (N. obilterata)

Null Hypothesis: There is no significance difference for decrease in mass between

Janet Craig (D. deremensis) and Kimberly queen fern (N. obliterata)

Mass

± 0.01g

Plants

Janet Craig (D. deremensis)

Kimberly queen fern (N. obliterata)

Difference between Janet Craig and Kimberly queen fern

1 trial

2.330

2.000

0.330

2 trial

2.320

2.740

0.420

3 trial

2.330

2.740

0.410

Mean

2.327

2.493

0.387

Std. Dev

0.005

0.349

0.040

Std. Error

1.343

1.440

0.223

Degree of freedom

2.000

Critical value at 5% level

4.300

t-value

1.734

| t | = 1.734 < 4.300

Thus, null hypothesis is rejected. The mean difference is not significant.

TABLE 18: TABLE OF T-VALUE FOR THE COMPARISON OF MEAN BETWEEN JANET CRAIG (D. deremensis) AND SNAKE PLANT (S. trifasciata)

Null Hypothesis: There is no significance difference for decrease in mass between

Janet Craig (D. deremensis) and Snake plant (S. trifasciata)

Mass

± 0.01g

Plants

Janet Craig (D. deremensis)

Snake plant (S. trifasciata)

Difference between Janet Craig and Snake plant

1 trial

2.330

1.950

0.380

2 trial

2.320

1.950

0.370

3 trial

2.330

1.940

0.390

Mean

2.327

1.950

0.380

Std. Dev

0.005

0.005

0.008

Std. Error

1.343

1.126

0.219

Degree of freedom

2.000

Critical value at 5% level

4.300

t-value

1.735

| t | = 1.735 < 4.300

Thus, null hypothesis is rejected. The mean difference is not significant.

TABLE 19: TABLE OF T-VALUE FOR THE COMPARISON OF MEAN BETWEEN JANET CRAIG (D. deremensis) AND HIMALAYAN BALSAM (I. glandulifera)

Null Hypothesis: There is no significance difference for decrease in mass between

Janet Craig (D. deremensis) and Himalayan Balsam(I. glandulifera)

Mass

± 0.01g

Plants

Janet Craig (D. deremensis)

Himalayan Balsam(I. glandulifera)

Difference between Janet Craig and Himalayan Balsam

1 trial

2.330

0.690

1.640

2 trial

2.320

0.700

1.620

3 trial

2.330

0.680

1.650

Mean

2.327

0.690

1.640

Std. Dev

0.005

0.008

0.013

Std. Error

1.343

0.398

0.947

Degree of freedom

2.000

Critical value at 5% level

4.300

t-value

1.732

| t | = 1.732 < 4.300

Thus, null hypothesis is rejected. The mean difference is not significant.

TABLE 20: TABLE OF T-VALUE FOR THE COMPARISON OF MEAN BETWEEN FLORIST'S MUM (C. morifolium) AND KIMBERLY QUEEN FERN (N. obliterata)

Null Hypothesis: There is no significance difference for decrease in mass between Florist's mum (C. morifolium) and Kimberly queen fern (N. obliterata)

Mass

± 0.01g

Plants

Florist's mum (C. morifolium)

Kimberly queen fern (N. obliterata)

Difference between Florist's mum and Kimberly queen fern

1 trial

2.810

2.000

0.810

2 trial

2.810

2.740

0.070

3 trial

2.810

2.740

0.070

Mean

2.810

2.493

0.327

Std. Dev

0.000

0.349

0.349

Std. Error

1.622

1.439

0.189

Degree of freedom

2.000

Critical value at 5% level

4.300

t-value

1.730

| t | = 1.730 < 4.300

Thus, null hypothesis is rejected. The mean difference is not significant.

TABLE 21: TABLE OF T-VALUE FOR THE COMPARISON OF MEAN BETWEEN FLORIST'S MUM (C. morifolium) AND SNAKE PLANT (S. trifasciata)

Null Hypothesis: There is no significance difference for decrease in mass between Florist's mum (C. morifolium) and Snake plant (S. trifasciata)

Mass

± 0.01g

Plants

Florist's mum (C. morifolium)

Snake plant

(S. trifasciata)

Difference between Florist's mum and Snake plant

1 trial

2.810

1.950

0.860

2 trial

2.810

1.950

0.860

3 trial

2.810

1.940

0.870

Mean

2.810

1.950

0.860

Std. Dev

0.000

0.005

0.005

Std. Error

1.622

1.126

0.497

Degree of freedom

2.000

Critical value at 5% level

4.300

t-value

1.730

| t | = 1.730 < 4.300

Thus, null hypothesis is rejected. The mean difference is not significant.

TABLE 22: TABLE OF T-VALUE FOR THE COMPARISON OF MEAN BETWEEN FLORIST'S MUM (C. morifolium) AND HIMALAYAN BALSAM (I. glandulifera)

Null Hypothesis: There is no significance difference for decrease in mass between Florist's mum (C. morifolium) and Himalayan Balsam (I. glandulifera)

Mass

± 0.01g

Plants

Florist's mum (C. morifolium)

Himalayan Balsam(I. glandulifera)

Difference between Florist's mum and Himalayan Balsam

1 trial

2.810

0.690

2.120

2 trial

2.810

0.700

2.110

3 trial

2.810

0.680

2.130

Mean

2.810

0.690

2.120

Std. Dev

0.000

0.008

0.008

Std. Error

1.622

0.398

1.223

Degree of freedom

2.000

Critical value at 5% level

4.300

t-value

1.733

| t | = 1.733 < 4.300

Thus, null hypothesis is rejected. The mean difference is not significant.

TABLE 23: TABLE OF T-VALUE FOR THE COMPARISON OF MEAN BETWEEN KIMBERLY QUEEN FERN (N. obliterata) AND SNAKE PLANT (S. trifasciata)

Null Hypothesis: There is no significance difference for decrease in mass between

Kimberly queen fern (N. obliterata) and Snake plant (S. trifasciata)

Mass

± 0.01g

Plants

Kimberly queen fern (N. obliterata)

Snake plant

(S. trifasciata)

Difference between Kimberly queen fern (N. obliterate)

1 trial

2.000

1.950

0.050

2 trial

2.740

1.950

0.790

3 trial

2.740

1.940

0.800

Mean

2.493

1.950

0.547

Std. Dev

0.349

0.005

0.351

Std. Error

1.439

1.126

0.316

Degree of freedom

2.000

Critical value at 5% level

4.300

t-value

1.731

| t | = 1.731 < 4.300

Thus, null hypothesis is rejected. The mean difference is not significant.

TABLE 24: TABLE OF T-VALUE FOR THE COMPARISON OF MEAN BETWEEN KIMBERLY QUEEN FERN (N. obliterata) AND HIMALAYAN BALSAM (I. glandulifera)

Null Hypothesis: There is no significance difference for decrease in mass between

Kimberly queen fern (N. obliterata) and Himalayan Balsam(I. glandulifera)

Mass

± 0.01g

Plants

Kimberly queen fern (N. obliterata)

Himalayan Balsam(I. glandulifera)

Difference between Kimberly queen fern and Himalayan Balsam

1 trial

2.000

0.690

1.310

2 trial

2.740

0.700

2.040

3 trial

2.740

0.680

2.060

Mean

2.493

0.690

1.803

Std. Dev

0.349

0.008

0.349

Std. Error

1.439

0.398

1.041

Degree of freedom

2.000

Critical value at 5% level

4.300

t-value

1.732

| t | = 1.732 < 4.300

Thus, null hypothesis is rejected. The mean difference is not significant.

TABLE 25: TABLE OF T-VALUE FOR THE COMPARISON OF MEAN BETWEEN SNAKE PLANT (S. trifasciata) AND HIMALAYAN BALSAM (I. glandulifera)

Null Hypothesis: There is no significance difference for decrease in mass between

Snake plant (S. trifasciata) and Himalayan Balsam(I. glandulifera)

Mass

± 0.01g

Plants

Snake plant (S. trifasciata)

Himalayan Balsam(I. glandulifera)

Difference between Snake plant and Himalayan Balsam

1 trial

1.950

0.690

1.260

2 trial

1.950

0.700

1.250

3 trial

1.940

0.680

2.620

Mean

1.950

0.690

1.710

Std. Dev

0.005

0.008

0.643

Std. Error

1.126

0.398

0.987

Degree of freedom

2.000

Critical value at 5% level

4.300

t-value

1.733

| t | = 1.732 < 4.300

Thus, null hypothesis is rejected. The mean difference is not significant.

7.6 Analysis on mass of formalin

From my prediction, only the indoor plants could eliminate indoor pollutants; as in this case the chemical formalin. While the outdoor plants are unable to do so. But I found out that decrease in mass of formalin in the entire 50ml beakers that contained the chemical is influenced by the ineffectiveness of the transparent chamber, which therefore rejects the theory that indoor plants transpiration alone could remove the pollutant. The ineffectiveness is referring to the external air movement that causes evaporation of formalin.

According to the data processed, the percentage of formalin absorbed by each of the plants shows a very close difference to one another and it is irrelevant to assume that all the formalin that was lost was via transpiration. Further research was made to explain these big differences. I concluded that the difference in rate of transpiration in plants affect the rate at which volume of formalin is decreased. Thus, the greater the transpiration rates of a plant, the better quality of air it produces. My assumption on this is because of the availability amount of water vapor that could be emitted out by the leaves of the plants is great when the rate of transpiration of a plant is high. This enables more mixing of the water vapor in the atmosphere with the vaporized chemical. This means, there would be more ‘food' that is available to be broken down by the microbes at the root system of a plant. Of all the six plants chosen to be experimented, only 4 of them have high transpiration rates. They are Janet Craig (D. deremensis), Boston fern (N. exaltata), Kimberly queen fern (N. obliterate), and Florist's mum (C. morifolium)[14]. The other two plants which are Snake plant (S. trifasciata) and Himalayan Balsam (I. glandulifera) have a much lower rate of transpiration when compared with the 4 plants.

7.7 Analysis on pH of formalin

Formalin is acidic in nature and there should not be any change in pH of the formalin in the beaker because generally, a buffer; carboxylic acid is present in formalin.[15] With the buffer, the solution would be able to resist any change in pH even though there is any external factor that could alter the pH of the solution. Hence, the pH should remain constant. But since there is a change in the value of pH of the formalin contained in the 50ml beaker in all of the 6 transparent chambers, I then make an early assumption that the carboxylic acid that is contained in the solution does not buffer.[16] That was why the pH value of the formalin in the beaker in all of the 6 transparent chambers increased throughout the 14 days duration of experiment. There must be an external factor present in the chamber that affected the acidity of the formalin. Throughout my findings, I found an explanation for this. Formalin acts as a reducing agent.[17] Thus it can undergo oxidation which could release its hydrogen.[18] As formalin evaporates, it is being oxidized to become CHO+. The hydrogen would then combine with the water vapour emitted by the plants via transpiration; from H2O, becoming H3O+. These ions which are available in the air would be fixed by the microbes at the roots of the plants, becoming the source of food for the plants.

7.8 Analysis on the external condition of plants

The external condition of the plants becoming worse as the experiment was carried out. Alteration of the colour of the edge of the leaves form green to yellow[19] and brown[20] and wilting of flowers[21] was due to the insufficient of water. Thus, it can be said that when the plant is lack of water, it would not be efficient in removing pollutants. The plants got dried up; changing colour from green to brown thus there was no stomata opening because the guard cells die. Eventually, the transfer of chemical downwards to the roots of the plants will not happen. It can be assumed that for plants that got dried up towards the end of experiment that the colour of the leaves started to become brown, the rate at which the mass of formalin decreases was not mainly supported by the process of vaporized chemical being absorbed through the stomata. Perhaps the colonies of bacteria are still present at the roots of the plants with this condition but the rate of decrease of formalin mass is reduced, not as rapid as the initial rate.

8.0 Conclusion

From the data obtained, I conclude that one of the observable changes in the quantity of the formalin is the mass. This is influenced by the evaporation of the formalin. The percentage of formalin that could evaporate is minimized by having the transparent chamber to cover the plant and 10ml of formalin which means the evaporation of formalin was not greatly affected by wind movement. It is therefore possible for chosen indoor plants; Janet Craig (D. deremensis), Boston fern (N. exaltata), Kimberly queen fern (N. obliterate), Florist's mum (C. morifolium), Snake plant (S. trifasciata) and Boston fern (N. exaltata) to remove the toxin, formaldehyde as there is quite large decrease in the mass of the formalin. Though Snake plant (S. trifasciata) does not have a high transpiration rate, it can still remove formalin quite large in quantity. I believe that this is affected by the factors such as number of holes poked onto the chamber, the external wind movement and some more mentioned in the evaluation part. (Please refer to 9.0)

As for Himalayan Balsam (I. glandulifera), an example of outdoor plant, it is probably able to remove indoor pollutant but just in small percentage as seen in the ranking done in the data processing, this plant provides the lowest quality of air in the chamber due to contamination by the pollutant formalin. It could just remove formalin for about 7.160% in 14 days duration. Besides, the only plant that experienced a rapid external change was Himalayan Balsam (I. glandulifera). The edges of the leaves become brown on the twelfth day. One of the closest possibilities is due to the failure of the experimenter to follow the period of watering everyday that it received less water.[22] It might be due to a very small surface area of this plant that it was deficient for it to cope with the concentrated amount of formalin in the chamber added as before the experiment was conducted properly, I have tried including the same amount of formalin in a chamber containing less than 10 leaves and the same result occurred during the 8 day interval.

Referring to the T-test in table 11 to table 25, all of the t- values were rejected because it lied in the critical region. The null hypothesis selected suggested that there was no significance between the differences of mass decrease between the plants. For the data to correspond with the predicted result, null hypothesis should be accepted. But because the pattern of formalin mass decreasing was too small from one interval to another, some of the values of standard deviation obtained are zero. That was why the mass differences between the plants are not significant when the t-values are all less than the critical value at 5% level which is 4.300. Thus, the null hypothesis stated that the mass differences are not significant to each other. This did not indicate the unreliability of the data but it showed that limitations and weaknesses were present in the experiment.

There is an increase in pH of the formalin and the pattern somehow shows that the acidity of the chemical has already decreased. The assumption made through the research made for this experiment was indoor plants have the ability to get rid of formaldehyde, one of the noxious wastes commonly found at home nowadays.

9.0 Evaluation

There were several weaknesses in the procedure throughout the experiment. I have come out with some suggestions on what to be improved on the aspect of methodology and the aspect of apparatus and materials used so that the experiment would give a reliable result when it is repeated in the future.

Regarding the technique to measure the acidity of chemical formalin, I found out that it was unreliable. The pH meter sometimes failed to function well. Sometimes, pH meter detect acidic chemical to be having a pH value more than 7. It is highly suggested to use colourimeter because this instrument could give the exact concentration of hydrogen, H+ in the solution[23] enabling the calculation of its pH by using the following formulation;

pH= -log10 (concentration of H+ ions)

Next, there was failure to exactly follow the watering time for all plants in the chamber which eventually affected the external condition of plants. Thus, a time table has to be prepared in the future so that the watering time is made standard each day.

Other than that, there was a pot of plant with one of its leaves had fallen into the beaker containing formalin. This should not happen because it could have left effect onto the acidity of the formalin. Place the beaker of formalin further from the pot of plant in the chamber so that neither leaves nor flowers would fall into the beaker.

Lastly, number of holes poked onto some of the transparent chambers which were not fixed. In my opinion, this is one of the causes of inefficiency of the chamber. The more holes present, the more rapid would the evaporation of chemical be. Therefore, fix the number of holes poked. For a better result, use a square plastic aquarium being inverted with 2 square polystyrene as its base. This would allow less movement of air but able to provide oxygen for the plants in the camber.

All in all, the hypothesis of the experiment is accepted. It is proven that the indoor plants are able to remove indoor pollutants while plants that are not indoor plants are able to remove indoor pollutants with a lower rate. Thus the public can now use this concept to provide good air quality at homes.

[1] 14th August 2009, https://www.rosefloral.com/nsplnt.htm

[2] 14th August 2009, https://www.rosefloral.com/nsplnt.htm

[3] 14th August 2009, https://www.rosefloral.com/nsplnt.htm

[4] 16th August 2009, https://www.ecomall.com/greenshopping/houseplants.htm

[5] 28th August 2009, https://www.annieappleseedproject.org/plancleanina.html

[6] 28th August 2009, https://www.annieappleseedproject.org/plancleanina.html

[7] 14th August 2009, https://www.rosefloral.com/nsplnt.htm

[8] 28th August 2009, https://www.atsdr.cdc.gov/toxprofiles/phs111.html

[9] 19th December 2009, https://stainsfile.info/StainsFile/prepare/fix/agents/formalin.htm

[10] 19th December 2009, https://www.chemguide.co.uk/inorganic/redox/definitions.html

[11] 25th July 2009, https://www.homemadesimple.com/en_US/nbrcontent.docontentType=op&articleId=ar067

[12] 25th July 2009, https://www.homemadesimple.com/en_US/nbrcontent.docontentType=op&articleId=ar067

[13] 28th August 2009, https://www.atsdr.cdc.gov/toxprofiles/phs111.html

[14] 28th August 2009,https://www.annieappleseedproject.org/plancleanina.html

[15] 28th August 2009, https://www.jbc.org/cgi/reprint/105/1/157.pdf

[16] 28th August 2009, https://www.jbc.org/cgi/reprint/105/1/157.pdf

[17] 19th December 2009, https://stainsfile.info/StainsFile/prepare/fix/agents/formalin.htm

[18] 19th December 2009, https://www.chemguide.co.uk/inorganic/redox/definitions.html

[19] 24th October 2009, https://www.bellaonline.com/articles/art51546.asp

[20] 24th October 2009, https://www.gardeningknowhow.com/problems/what-causes-brown-edges-on-leaves-of-plant.htm

[21] 24th October 2009, https://en.wikipedia.org/wiki/Wilting

[22] 24th October 2009, https://www.gardeningknowhow.com/problems/what-causes-brown-edges-on-leaves-of-plant.htm

[23] 26th August 2009, https://en.wikipedia.org/wiki/Colorimeter

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