• If you are citizen of an European Union member nation, you may not use this service unless you are at least 16 years old.

  • Whenever you search in PBworks, Dokkio Sidebar (from the makers of PBworks) will run the same search in your Drive, Dropbox, OneDrive, Gmail, and Slack. Now you can find what you're looking for wherever it lives. Try Dokkio Sidebar for free.


Car Exhaust Effects on Plants 0708

Page history last edited by PBworks 14 years, 8 months ago
 Car Exhaust Effects on Plants
-Ye Chan Hur-







Description and Rationale



Most of the cars in the country of the Philippines were originally imported from other countries. Jeepneys, the most unique public transport only in the Philippines, have been made by local Filipinos since the end of the Second World War. These new sorts of vehicles have been proliferated over the country. Nowadays, the Philippines with the jeepneys, producing great amount of car exhaust.


What is the vehicle’s effect on the plants in the Philippines? What factors exactly contribute to the effect? What is car exhaust composed of? Does the car exhaust affect the growth of the plants? Do the jeepneys produce worse car exhaust than other cars? Does the car exhaust also have an effect on fruits? Are the plants capable of filtering the car exhaust? Is the exhaust gas really bad for the plants? If it is, what does it do to the plants? What components in the car exhaust affect the plants?


Might there be any ways to reduce the effect of the car exhaust the plants? If the amount of car exhaust that is produced is reduced, how would it affect on the plants? It is proven that if the car exhaust is combined with the water in the air, it turns into acid. If the rain comes down with this acid, it acidifies the land, even the land in the countryside. If the soil absorbs the acid rain, it gets acidity in it, making plants not to grow well. Would the car exhaust affect the plants directly? If it can, how effect would it have on the plants? One student named Tom Witherell had an experiment on this, and surprisingly, the plants that were exposed more exhaust grew better. What would be the reason for this result? If it is proven to be true, it would help people in the Philippines to grow their crops or plants.


The initial purpose of this project will be to research the components of the car exhaust and its effect on the growth of the plants, through a research of the Internet and interviews with the car or jeepney drivers. The experiment similar to Tom Witherell’s would be done to make sure that I get the same result. The initial research and the findings will help and guide my experiment.


It is hoped that new facts about the car exhaust might help the conditions and the growth of the plants in the Philippines. It would also help farmers who might have false knowledge on the effects of car exhaust.



table of contents...



Common Names and Synonyms

 Buxus sempervirens is also called the common boxwood. The name of the boxwood is derived from the stems of boxwood which are strongly four-sided and are square in cross-section like a box. Other synonyms include Buis (France); Modera de Boj (Spain); and Bukszus (Hungary).




Kingdom: Plantae

Phylum: Tracheophyta (Vascular plants)

Class:  Magnoliopsida (flowering plants)

Order:  Euphorbiales (dicotyledonous plants)

Family:  Buxaceae (widely distributed evergreens)

Genus:  Buxus (Boxwood)

Species: B. sempervirens (evergreen)


There are many species of boxwood that have different scientific names. They are classified according to the place where they live and the size of the leaves. There are many sub-species such as Buxus suffruticosa.


table of contents...


Morphology and Physical Description





The plant can grow up to 15 to 20 feet in height and 15 to 20 feet in width. Sempervirenses are densely branched, slow-growing shrubs with many smooth-edged leaves. The leaves are usually dark green and they remain on the plant all winter, which means that it is a type of evergreen plant. The leaves usually grow up to 0.5 to 1 inch long. Its foliage (plant leaves) is arranged in opposite ways. The shape of a leaf is oblong and ovate, which means that it’s rectangular and oval.


The sempervirenses form flowers from April to May, and the seeds ripen in September. The color of the flower is green. The flowers are scented and monoecious (have both sexes). Each flower is either male or female, but it is discovered that both sexes can be found on the same plant. This plant produces fruits and they are covered in dry, hard skins. The fruits grow less than 0.5 inches, therefore they are inconspicuous (not showy). Its trunk and branches are typically multi-trunked or branched.


In addition, this species grows less than 12 inches per year. It can live up to six hundred years. The boxwood prefers well-drained soil, but can grow in clay soil. It is known that all parts of the Buxus sempervirenses are poisonous.



table of contents...



Getting Food


The sempervirenses are autotrophs (producers), which capture the sun light and use it as energy to make organic molecules. They use photosynthesis; these plants obtain carbon dioxide for photosynthesis from the air through stomata. They also absorb water from the ground.




The sempervirenses reproduce by pollination and fertilization, which means that this plant produces seeds. Pollen is produced in the stamens and it is usually pollinated by bees and flies that are attracted by the scent. After pollination, fertilization takes place; pollen goes through a pollen tube to an egg and the sperm reaches the egg.


Environmental Factors


The sempervirens grow well in semi-shade (part shade and part sun area). This plant can also be found in dappled shade or in shady edges. However, the sempervirenses can grow in almost any soil that is well-drained, and it tolerates a pH range from 5.5 to 7.4. The boxwood can tolerate temperatures down to at least -23°c.

There are several disease organisms that may affect or use the the sempervirens as a host. These include general debilitation, viruses and parasitic infestations such as the boxwood leaf miner. However, the plant usually has long-term health.


table of contents...



Origin and Distribution


The origin of the sempervirens has not been fully discovered. Some possible places are southern Europe, the Middle East or Asia. The Buxsus species has been introduced to almost all the countries around the world. It has been able to survive and thrive in a variety of tropical and cold environments.


Importance to People



The sempervirens is very well-known as an excellent hedge reaching height from 45 cm to 4.5 meters. It is often used as topiary, meaning that the hedge is trimmed to form different animals or ornamental shapes. The other ways that gardeners use the Buxus are to provide background for other plantings, to provide a framework of a formal garden, to outline a terrace, or walkway or parking area.

The common boxwood has no value as food, but the leaves have been used to make beer as a substitute for hops in France. However, it cannot be very wholesome to people. Surprisingly, it is found out that this plant has been used medically in the past. People used it as a sedative and treatment for syphilis. The leaves and the bark have also been used for many other medical treatments (catharsis or vermifuge). The leaves have also been used as a substitute for quinine in the treatment of malaria. Nevertheless, the plant is very rarely used in modern herbalism. Additionally, this plant, with other kinds of boxwood, was used to fertilize the land during the 18th centuries in France.


"Looking for the worse field, if there is a boxwood tree, the soil underneath it will be rich, since the leaves fallen each year will have successively fertilized and improved it." (Departmental archives from Herault, Serie D, cote 181-1773).



Survivability and Endangered Status


The resilience of the common boxwood is medium. The plant has a very slow growth rate; it grows less than 12 inches per year. The sempervirens is not an invasive species in the Philippines, but due to its tolerance for types of soil and temperatures, it has been spread all around the country. Also, other herbivores are not able to eat this plant, because it’s poisonous to them; sometimes its lethal.


table of contents...


Potential Solutions


How does car exhaust affect on plants? It is commonly known that the car exhaust fumes tend to reduce the growth of the plants, but is it really true that the car exhaust is actually bad for the plants? It wasn’t clear how it is bad or good to the plants. Further research about the car exhaust fumes and an experiment are necessary before determining if the car exhaust fumes are threats of the life of the plants in the Philippines. If it is found out that the exhaust fumes are somehow beneficial to the plants, there would be several possibilities that may be able to benefit the farmers and people those who grow plants in greenhouses in the country of the Philippines. Below are three possibilities with the action step and an analysis of the advantages and disadvantages for each.





What would happen to a plant if it’s exposed to car exhaust fumes? This initial question has led me to do the experiment on the boxwood, the experimental plants. The initial hypothesis was that the plant exposed to the car exhaust would have reduction in its growth rate. However, the result was quite different.


Data chart of the experiment                         **CU: Change Unseen





During the experiment, I filled up the plastic bag with car exhaust fumes and covered it on the plant #2. The plastic bag filled with the car exhaust fumes was changed every two days. Despite the fact that the plant #2 was taller than #1 even before the experiment, the result definitely shows that the car exhaust actually helped the growth rate of the plant. What factor would have caused the controlled plant to grow better than the other one? Car exhaust contains CO2, which is turned into carbohydrates for the plants to use it for its growth. CO2 is also an important factor for the processes of photosynthesis and Calvin Cycle.








1. Since the experiment has proven that if the plants are able to inhale the certain amount of car exhaust fumes, it would be possible to use it in variable ways; it can be used as a fertilizer for the plants.


2. It can be a solution to air pollution of the Philippines. (It’s going to be described in more details on Possibility 2)



1. The amount of car exhaust that the plants inhale must be limited. If the amount of the car exhaust goes over the amount of the plant can bear with, the plants can be damaged by sulfur dioxide. Sulfur dioxide enters through the stomata and turns the plants to brown, which means the loss of the chlorophylls. It is uncertain about the amount of the car exhaust fumes that the plants can actually handle.



2. Since the plants are interacting with the chemicals, there is a risk of the plants having mutations. It means that if these plants bear fruits, it might be not safe for both humans and animals. The fact is that food that we eat could have come from this process. This problem must be solved to fulfill what the Lord has told us; in Genesis 1:28, it says that “…Rule over the fish of the sea and the birds of the air and over every living creature that moves on the ground.” We should be considering not only about ourselves, but about all the creatures on the earth.


table of contents...




 The people and the government of the Philippines are putting their effort on re-greening the country by planting trees. Several projects, such as Green Philippine Highway Project and The Luntiang Pilipinas Movement, are being done by the Filipinos and the government.



1. Many people from different age groups are participating in this, which means that the Filipino people are aware of the pollution and the things that are happening to the environment of the Philippines. By different projects, the people in the Philippines are being encouraged to participate in the projects.


2. The trees are not just planted to re-green the country. They can be used to aid the local people as sources of fuel and food.




1. The trees are mostly planted off the main cities of the Philippines, near the countryside of the country. There are few environmental treatment and project taking place within the cities.


2. The main cities where the most of the pollutions take place have heavy population density. To plant the number of trees for solving the air pollution, there must be sufficient space for them to be planted, but there aren’t enough space for that number of the trees.


table of contents...




 Through the experiment, it has been proven that the car exhaust fumes can act as a fertilizer for the plants. To share this new information with the local people, I have visited the plant nursery and have interviewed with one of the people who work in the nursery. His name is Jake and he said that he never knew about this new information. In Genesis 2:15, it says that the Lord God took the man and put him in the Garden of Eden to work it and take care of it. I think that these people who are working at the plant nursery work something like this man, Adam. They are actually taking care of the things that are belonged to God.


(The guy in the red T-shirt is Jake)





1. People do not have to buy other fertilizer for their plants. Since the experiment has proven that the exhaust fumes are quite helpful for the growth of the plants, people would not feel the necessity of other fertilizers.


2. Through the interview with Jake, I was able to learn that this plant nursery does not put much effort on fertilizing the soil. The plants were totally exposed to the car exhaust fumes and it might have worked as the fertilizer.




1. We cannot ignore that fact that once the plants are exposed to the car exhaust, there is a possibility for the plants to be infected. Therefore, it is quite risky to use this method when people grow plants. However, if it is possible to control the amount of the car exhaust fumes exposing to the plants, it would be okay to use it as the new type of fertilizer.


2. To control the amount of the car exhaust inhaled by the plants, people would have to grow their plants in greenhouses, so that the plants are not exposed to too much of the exhaust gas. The exhaust fumes needed for the plants in the greenhouses would have to be collected somehow.

table of contents...





“Boxwood (Buxus)-Genus” Gardenguides.com. 13 April. 2008



“Buxus sempervirens-L.” Plants for a Future. 13 April. 2008                     



"Car." World Book. 2006.


Christman, Steve. “Buxus microphylla.” Floridata.com. 13 April. 2008



“Environmental Initiatives.” GreenMap; Philippines. 30 April. 2008                



Evans, Erv. “Scientific Name:Buxus sempervirens.” Edu.com. 13 April. 2008  <http://www.ces.ncsu.edu/depts/hort/consumer/factsheets/shrubs/buxus_sempervirens.html>


Griffiths, Heather. “Effects of Air Pollution on Agricultural Crops” Ontario. 30 April 2008.



Jake. Personal Interview. 3 May 2008.


“Luntiang Pilipinas Movement: Eight years of re-greening the city” Manila Bulletin online. 28 October, 2006 . Alchemy Solutions. 30 April. 2008                    <http://www.mb.com.ph>


Mallari, Perry. “Regreening Baguio.” The Manila Times. 13 July, 2007. Cybernet Solutions. 4 May. 2008                                                      

< http://www.manilatimes.net/national/2007/july/13/yehey/life/20070713lif1.html>



Relf, Diane. “Boxwood in the Landscape.” Edu.com. June 2001. 13 April. 2008



Republic of the Philippines. “Green Philippine Highway Project” Department of the Interior and Local Government. 30 April. 2008



Republic of the Philippines. Department of Environmental and Natural Resources. 30 April. 2008



Winston. Modern Biology. Austin: A Harcourt Classroom Education Company, 2002.


Witherell, Tom. “The Effects of Car Exhaust on Plant Growth”  Pajarito Environmental Education Center. 4 Arpil. 2008                                           



“Why are they called boxwood.” The United States National Arboretum. 24 March. 2004. 13 April. 2008   <http://www.usna.usda.gov/Support/index.html>



table of contents...









Comments (0)

You don't have permission to comment on this page.