Toxicity and Air Pollution PDF Print E-mail
Written by Dr. Rehan Zaidi   
With the many comforts that city life has provided man, it has also taken a toll on man's health. Living off of the land, being surrounded by nature, and doing a hard day's work without the luxury of modern-day technology, though definitely limiting the pollutants one is exposed to, for most is just not practical today.  Instead, everything from going to work to living at home means putting up with a variety of air contaminants. Nevertheless, despite being surrounded by so much pollution, there are steps that people can take to reduce the overall toxic load they are exposed to daily. Below are common air pollutants whose presence can be minimized from around our homes with a little awareness and understanding.
 
Home appliances

As the temperature drops, the use of fuel-powered appliances increases. Home appliances, such as gas or oil furnaces, gas refrigerators, gas clothes dryers, gas ranges, gas water heaters or space heaters, fireplaces, charcoal grills, and wood burning stoves burn hydrocarbon fuels. Heating appliances, for instance, are commonly used throughout Jordan and are usually safe. However, under certain conditions, these appliances can produce combustion pollutants, such as carbon monoxide, that can damage your health, or even kill you.
 
What is Carbon Monoxide?
 
Carbon monoxide (CO) is one of the leading causes of poisoning deaths throughout the world. Carbon monoxide is a colorless, odorless deadly gas produced from the improper burning of hydrocarbon fuels. Because you can't see, taste, or smell it, carbon monoxide can kill you before you know it's there. Although CO is harmful to anyone exposed to it, individuals with greater oxygen requirements, such as unborn babies, infants, children, senior citizens, and people with coronary or respiratory problems, are at greater risk.
 
Where does CO come from?
 
Before understanding what CO is, it is important to understand what hydrocarbons are. Hydrocarbons are basically a group of substances that are made up of carbon and hydrogen molecules. They are the main substances that make up fuels and are also found in paints, paint and spot removers, dry cleaning solutions, lamp oil, lubricants, rubber cement, and solvents as well.
Hydrocarbons can be derived from either petroleum or wood. Petroleum distillates include kerosene, gasoline, and naphtha, while wood-derived hydrocarbons include turpentine and pine oil. Most hydrocarbons are liquid, but some (eg. propane) are gas, while others (eg, waxes) are solid at room temperature. Although hydrocarbons are dangerous in themselves if inhaled or ingested, the larger risk they pose to the general public is when they produce CO from improper burning. CO is not a normal by-product, but is produced when there is an inadequate supply of oxygen, ie. poor ventilation.
Burning a hydrocarbon fuel nearly results in a complete combustion reaction when oxygen is present, as from the air in our environment. A simplified example is:
 
The normal by-products from burning these fuels are carbon dioxide and water vapor. However, as the oxygen supply in the room is depleted by the combustion of the fuel as well as by people breathing, carbon monoxide (a carbon with one oxygen molecule attached to it) is released instead of carbon dioxide (a carbon with two oxygen molecules attached to it).Symptoms of CO poisoningThe great danger of carbon monoxide is its attraction to hemoglobin in the bloodstream. When breathed in, CO replaces the oxygen which cells need to function. When CO is present in the air, it rapidly accumulates in the blood and begins to poison a person. Unfortunately, CO poisoning can very easily be overlooked due to its non-specific symptoms, which are similar to the flu. During the initial stages people may complain of:
-throbbing headaches -fatigue -nausea
-dizzy spells
-confusion
-irritability.

The following groups of symptoms appear at greater levels of poisoning:
-vomiting
-muscle weakness
-loss of consciousness
-coma
-convulsions
-eventually brain damage
-death
 
As one can see, these symptoms can easily go unnoticed when a person has an existing illness that manifests a similar symptom-picture or is pregnant, for example. Furthermore, as these people remain indoors for longer because of their "illness", they are only getting sicker in the meantime. One keynote feature of CO poisoning however, is a drastic improvement as one goes outside.
 
Remember that infants and children may be affected more quickly by carbon monoxide. Be sure to see if they are exhibiting symptoms even if others in the home are not. If CO is discovered, ventilate the home with fresh air, turn off all potential sources of carbon monoxide and have a qualified technician inspect your combustion appliances. Do not just shut off the CO detector and wait for the gas to dissipate on its own.
Other by-products
 
The health effects of the other pollutants are generally more subtle and are more likely to affect susceptible people. It is always a good idea to reduce exposure to combustion pollutants by using and maintaining combustion appliances properly. Besides CO, there are other gases that can be released in the homes from combustion reactions. The reason is because in reality, combustion processes are never perfect or as complete as they have been mentioned above. In flue gases from combustion of hydrocarbons, both unburned carbon (as soot) and carbon compounds (CO and others) will be present. Also, when air is the source of oxygen, oxides of nitrogen (NOx) and sulfur are also produced in some amount.
 
Finally, as mentioned earlier, combustion always produces water vapor. Although water vapor is not usually considered a pollutant, it can become one. Jordanian homes often accumulate humidity and wet surfaces inside the home. These conditions encourage the growth of biological pollutants such as house dust mites, molds, and bacteria to which many people have allergies. Signs and symptoms of mold allergies, however, is a whole other discussion in itself.
 
Soot
 
Soot is the dark powdery deposit of unburned fuel residues (mainly carbon) that is visible in smoke.  Soot particles, such as polycyclic aromatic hydrocarbons (PAHs), are carcinogenic (cancer causing) for the lungs when inhaled if the particles are too small to be filtered out by the upper respiratory tract. Individuals with preexisting respiratory conditions, children, and the elderly are the most vulnerable to soot's lasting and deadly effects. People with heart disease, emphysema, asthma, and chronic bronchitis suffer from increased hospital admissions and emergency room visits as a result of exposure to soot.
 
Although the amount of soot inhaled is minimal from home appliances, slow and steady exposure over years has its repercussions. As for sudden exposures to excessive smoke and soot in the house, the home should be ventilated immediately, as mentioned earlier.
 
Soot also accumulates in chimneys and other surfaces responsible for exhaust fumes. It especially results from the incomplete combustion of fuel in the lack of sufficient oxygen. This build up is the reason that yearly cleaning of exhaust pipes is mandatory. Otherwise exhaust fumes may not exit from chimneys efficiently and slowly be released back into the home. Often times space heaters also produce excessive amounts of soot when they are first ignited as well as when they are extinguished, so both procedures should be performed in well-ventilated areas preferably outside the home.
 
Nitrogen compounds (NOx)
 
Breathing high levels of nitrogen dioxide causes irritation of the respiratory tract and impaired lung function in the short term as well as accelerated deterioration in lung function over the long term. Compared to healthy people, children, and individuals with respiratory illnesses such as asthma may be more susceptible to the effects of nitrogen dioxide.
Some studies have shown that children may have more colds and flu when exposed to low levels of nitrogen dioxide. When people with asthma inhale low levels of nitrogen dioxide while exercising, their lung airways can narrow and be more vulnerable to inhaled materials.
 
Sulfur Dioxide:
 
Sulfur dioxide at low levels of exposure can cause eye, nose, and respiratory tract irritations similar to NOx. At high exposure levels, it causes the lung airways to narrow. People with asthma are particularly susceptible to the effects of sulfur dioxide compared to the rest of the population. Some symptoms of sulfur dioxide in the air include wheezing, chest tightness, and various breathing problems such as asthma.
 
The Crux
 
Keep the following points in mind over the winter as you use combustion heating appliances and begin to experience cold and flu like symptoms:
  • Do your symptoms decrease when you leave home, and reappear when you return?
  • Are others in your household complaining of similar symptoms?
  • Do you stay in the home more than others?
  • Are your symptoms getting worse?
  • Do you often catch colds or get the flu?
  • Has anyone inspected your appliances lately? Are you certain they are working properly?
 
If a home is vented properly and is free from appliance malfunctions, air pressure fluctuations or airway blockages, carbon monoxide will most likely be safely vented to the outside. But as homes are more efficiently constructed and tightly sealed, they can trap polluted air in a home year-round. Furnace heat exchangers can crack, vents can become blocked, and inadequate air supply for combustion appliances can force contaminated air back into the home. Exhaust fans, clothes dryers and bathroom fans can also pull combustion products into the home.
 
To reduce exposure to combustion pollutants you should:
  • Choose vented appliances whenever possible.
  • Never ignore the smell of fuel. If you suspect that you have a fuel leak have it fixed as soon as possible.
  • Never use an unvented combustion heater overnight or in a room where you are sleeping.
  • Do not turn on exhaust fans when using vented appliances
  • Keep doors open to the rest of the house from the room where you are using an unvented gas space heater or kerosene heater, and crack open a window. This allows enough air for proper combustion and reduces the level of pollutants, especially carbon monoxide.
 
 
< Prev   Next >