6.
Indoor Air
Authors
The information in this chapter was prepared by the following individuals:
Introduction:
o Ben Chaiken, former director, Arizona Lung Association
Description of Asbestos:
o Tim Flood, M.D., Medical Director, Chronic Disease Epidemiology Section, Arizona Department of Health
Introduction
Indoor air pollution has become an increasing problem in our energy-conscious society. Architects, builders, etc. develop homes which are tightly sealed to make them more energy efficient. Gasses and chemicals released into these structures have caused considerable problems to workers, children and others with pre-existing cardiopulmonary disease.
Emissions from new carpeting, photocopying, cleaning solutions, and a myriad of other substances have caused cardiopulmonary symptoms to develop among those who spend hours in a working environment.
Chemicals and gasses from hobbyists in energy-efficient homes permeate the indoor air almost continuously. Releases from gas cooking, space heaters, fireplaces and second-hand smoke expose residents to substances which have acute and possibly long-term health effects.
The Committee, therefore, considered this an important issue to assess.
Asbestos
Asbestos is a group of fibrous minerals, including chrysotile, crocidolite, amosite, and actinolite. It has the special qualities of incombustibility, high tensile strength, and resistance to chemical degradation by most acids or bases. It is commonly found as an insulating material around hot pipes and boilers. It is also a strengthening agent found in some pipes, cement, fireproof materials and insulation tiles, brake linings, and other products.
Up until about 1970 asbestos was commonly used as a spray-on insulation material on ceilings, building girders, and ships. These past uses mean that asbestos is frequently encountered in our society today and will be around us for decades to come.
Despite its beneficial uses, asbestos is hazardous when materials containing asbestos are crushed, sanded, blown, or otherwise disturbed and dispersed into the air. The major hazard is to the lungs. Adverse effects include lung fibrosis called asbestosis (white lung), lung cancer, mesothelial cancer of the pleura (the lining of the lung), and possibly cancers of larynx, gastrointestinal tract, and other organs. These effects have been observed in workers who were exposed to relatively high levels at the workplace 30 to 50 years previously.
The Occupational Safety and Health Administration now has very restrictive rules regarding exposure levels and use of asbestos in the occupational setting. Millions of dollars have been spent in removing asbestos from schools and other public buildings.
Despite good intentions on the part of policy makers, removal of asbestos sometimes increases one's exposure to asbestos because the removal process can release previously stable asbestos. For that reason each project or site must be individually assessed to determine the best course of action for management of its asbestos- containing materials. Rules passed by the Occupational Safety and Health Administration require workers to be trained and qualified in order to remove asbestos.
Occupational studies have shown that asbestos exposure can double a worker's risk of developing lung cancer. These studies have also shown that cigarette smoking alone causes a five-fold increase in lung cancer risk. The combination of asbestos exposure and smoking causes a ten-fold increase in cancer risk.
At-Risk Groups
Persons at increased risk of asbestos-related disease include workers who knowingly handle asbestos, such as plumbers, insulators, and brake repairmen.
Other persons who can be exposed unwittingly include custodians and janitors, librarians who clean dust off books, and persons who perform their own house repairs.
Children who play on the floor of buildings with asbestos also can be exposed above the normal background levels.
Exposure Levels
There is much published data about asbestos levels at specific sites. However, it is difficult to generalize these findings with precision.
Quantitative Estimate of Health Effects
For non-cancer health effects, no cases of asbestosis would be expected based on the low level of current exposures.
Conclusion
Exposure in schools when children are five to 18 years of age might add 0.07 to 0.68 cancers per year.
Exposure in public buildings to persons 25 to 45 years of age might add 0.07 to 0.67 cancers per year.
Exposure to workers between age 25 and 45 might add 0.25 cancers per year.
Combining these high-end figures, an estimated 3.43 cancers of lung and pleural mesothelium occur per year due to asbestos in Arizona.
The Committee ranked asbestos as a comparatively low risk to Arizonans.