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The benefits of a respiratory filter researched by Vieira et al. (1) and the constructive editorial by Mentz and O’Brien (2) enhance the attention that has been given to the cardiovascular effects of air pollution.
In the eligibility criteria, patients with “uncontrolled arrhythmia or hypertension” were excluded from the study. Does this refer to the blood pressure recorded during the initial pre-study evaluation and history? Importantly, what were the cutoff points of systolic and diastolic pressures considered to be uncontrolled? The medications used in the treatment of hypertension and heart failure are often similar. Is it possible that specific endpoints and results could be influenced by the individual therapeutic programs? This may have significance, because the authors noted that diesel exhaust had no effect on heart rate variability. This is in contrast to the recent study by Lee et al. (3), which concluded that exposure to ambient fine particulate matter produced remarkably sudden acute changes in nocturnal heart rate variability in patients without known heart disease.
A micron (micrometer) is a unit of length equal to one-millionth (10−6) of a meter. Coarse particles are those considered to be >2.5 μm, and fine particles are 2.5 μm or less. Microfilters can (presumably) remove particulate matter from 2 to 5 μm in diameter.
Initial studies (epidemiological and clinical research) focused their attention on the respiratory and pulmonary effects of particulate matter, gases, and fumes. These studies were unanimous as to the positive causation of lung cancer and various inflammatory diseases of the entire respiratory system and gave additional consideration to less well-defined conditions such as leukemia, birth defects, reproductive problems, hormonal dysfunction, alterations in natural immune defense mechanisms, mutations in chromosomes, and damage to DNA. It became evident that air pollution contributed to excesses of morbidity and subsequent mortality and that toxic substance-induced pathophysiological cardiovascular effects were responsible for these excesses. These included angina pectoris, cardiac arrhythmia, myocardial infarction, progression of atherosclerosis, stroke, heart failure, and sudden cardiac death (4). Ambient air also contains ozone, carbon monoxide, sulfur oxide, nitrogen oxide, hydrocarbons, carbon dioxide, methane, various dusts and pollens, and numerous other chemical pollutants. Unbridled diesel fumes are one of the most toxic substances on earth, injurious to animal and plant life, as well as to all ecological aspects of the environment. Some manufacturers state that their present diesel engines are “clean,” but confirmatory studies are sparse or nonexistent. More than 15 years ago, the California Environmental Protection Agency noted that diesel exhaust (spent diesel fumes) contained more than 40 toxic contaminants, all significantly harmful, both individually and even more so in combination.
A personal quest, which began 3 decades ago, eventually resulted in the placement of recirculation air systems in automobiles and the addition of ventilation filters (5). Recirculation systems keep external air from entering the vehicle, and filtration systems capture ambient air particulates and, to some extent, diminish incoming fumes and odors. Both are necessary to decrease the harmful effects to the occupants of motor vehicles. At present, both systems need improvement. Automobile manufacturers should be required to state the type of filter used in the vehicle, as well as the performance of the filter in terms of particle size and effectiveness in fume and odor removal.
What else can the public (whether healthy or afflicted with certain diseases) do besides use personal respiratory filters? When applicable, avoid outdoor jogging, especially in known or expected areas of excess air pollution, and use indoor air “purification” systems. Importantly, do not buy an automobile without a ventilation filter, sometimes called in-cabin air filters. Preferably (in relation to cost) buy a car that has a filter that uses activated charcoal, carbon, carbonite, grape seed, etc., each of which adds additional cleansing of the incoming air.
Please note: Dr. RuDusky has reported that he has no relationships relevant to the contents of this paper to disclose.
- American College of Cardiology Foundation
- Vieira J.L.,
- Guimaraes G.V.,
- de Andre D.A.,
- Cruz F.D.,
- Saldiva P.H.,
- Bocchi E.A.
- Mentz R.J.,
- O’Brien E.C.
- Brook R.D.,
- Rajagopalan S.,
- Pope C.A. 3rd.,
- et al.
- RuDusky B.M.