Poor air quality has been known to impact human health for hundreds of years. However, only in the last few decades have we begun to collect scientific data that shows the long-term impact of poor air quality.
Poor Air Quality and Particulate Matter
Prior to the industrial revolution, the most significant cause of poor air quality’s impact on human health was the burning of wood, and later coal. Burning wood or coal results in fine particulate matter which is breathed into the lungs. Chimneys for indoor fires were first invented, not because of any knowledge or concern about air quality, but because prolonged exposure to smoke and soot irritates the eyes.
Since the industrial revolution the smoke and soot from burning has moved from the home to factories and outdoors. High levels of smoke and soot resulted in a haze over many cities at the turn of the century, and later became known as a component of “smog” in the US. Man-made smog is derived from coal combustion, vehicle and industrial emissions and ozone.
Today we have the ability to measure the particulate materials in smoke or soot using particle detectors. While there are different ways to measure particles, the most common use light or lasers that reflect off individual particles in an air sample. The amount of light reflected is directly proportional to the number of particles in the air sample. This technology allows particles to be measured down to the micron size.
PM 2.5 the most common reference for particulate measurement. It refers to 2.5 micron (0.0025mm) dimension of the particulate most often associated with pneumoconiosis. Particles 2.5 microns or less have been shown to have a significant long-term impact on human health. For this reason, PM 2.5 measurement is required as a standard worldwide when measuring air quality for health.
Note that in addition to particulate matter like soot and smoke, silicosis from dust, asbestos from insulation, composite materials and many other particles formed in the atmosphere as a result of chemical reactions that result in sulfur dioxide and nitrogen oxides emitted from power plants, industries and automobiles.
Poor Air Quality and Industry
The industrial revolution has brought about huge leaps of comfort, safety and economic success for the world. What is less considered is that it has also brought about many sicknesses not found before it. Some of the most common industrial by-products that contribute to poor air quality are:
Ozone (O3) occurs naturally in the upper atmosphere and is a protective layer against UV radiation bombarding the planet’s surface. However, man-made, ground-level ozone is formed primarily from photochemical reactions between volatile organic compounds (VOCs) and nitrogen oxides (NOx). Both these reactions require heat and sunlight.
While ozone protects life on earth, it is not safe to breath. People with asthma or lung disease are particularly sensitive to elevated ozone levels. In addition, exposure to ozone has been linked to bronchitis, pneumonia and emphysema.
Benzene is a colorless liquid that evaporates into the air very quickly. While it is found naturally in air, water and soil, it is mostly made from petroleum. One of the most produced chemicals in the US, benzene is used to make other chemicals such as
- Styrene (for Styrofoam® and other plastics)
- Cumene (for various resins)
- Cyclohexane (for nylon and synthetic fibers).
- Manufacturing of some types of rubbers, lubricants, dyes, detergents, drugs, and pesticides.
Benzene is also a by-product of burning coal, oil and gasoline.
While everyone is exposed to benzene naturally, elevated levels of exposure over the long term impact the tissues that form blood cells in the bone marrow. Long-term exposure to high levels of benzene in the air can cause leukemia, cancer of the blood-forming organs.
Formaldehyde is a colorless, flammable gas. Like benzene, formaldehyde can come from both natural and man-made sources. However it is exposure to man-made sources that have been linked to poor air quality and health risks.
Formaldehyde is produced industrially for many applications. For example, high levels of formaldehyde are found in home building products (particle-board, plywood, and furniture), automobile exhaust, paints and varnishes, carpets and permanent press fabrics.
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An increased risk of asthma or allergies have been observed in people who breathe in low levels of formaldehyde. Changes in lung function have been observed in people who breathe in formaldehyde at slightly higher levels.
Results of Poor Air Quality
All issues of poor air quality and health relate to the impairment of the lungs by a myriad of causes, all having several measurable attributes to diagnose for therapy.
The pathology of poor air quality on human health is interesting. For example, reduced lung function or lung disease is not always some viral culprit, it can and is as often a consequence of another disease or the use of a drug for the therapy for another malady.
However, the biggest issue faced with poor air quality is the steady rise of chronic lung problems including COPD, emphysema, pneumococcus (silicosis), mesothelioma (asbestos), pulmonary fibrosis and pulmonary hypertension. Many of these maladies will be reduced proportionally to the improvement of air quality in the home and workplace.