The respiratory system, which includes the trachea, the bronchi and the lungs can be a source of chronic inflammation that not only affects the respiratory system itself, but can affect other organs as well. The inflammatory process in the respiratory system involves activation of the immune system just like chronic inflammation in any part of the body. It includes pro-inflammatory cytokines, macrophages and lymphocytes.
Causes of respiratory system inflammation
Nitrogen Oxides
Nitrogen oxides, particularly nitrogen dioxide (NO2) is a respiratory irritant that causes inflammation of the bronchi. Exposure to NO2 can cause or exacerbate asthma. In addition, several epidemiological studies have demonstrated associations between NO2 exposure and premature death, chronic lung disease, heart disease, stroke, decreased lung function growth in children, respiratory symptoms, emergency room visits for asthma, and intensified allergic responses. A comprehensive review of the health effects of NO2 exposure, both acute and chronic, can be found at this website: The Health Impacts of NO2 Pollution. The biggest outdoor source of NO2 is through reactions between nitric oxide (NO) and other air pollutants (mostly from automobile exhaust) that require the presence of sunlight. The biggest source of NO2 in home air is the use of unvented natural gas stoves.
Particles
In addition to gases like NO2, air pollution also contains particles. Large and medium size particles lodge in the nose and upper airways and are usually cleared by the airway protective system which includes mucus and cilia that move these particles up and out of the airways. Fine and ultra fine particles (those that are 2.5 microns and smaller) can get all the way down to the alveoli (the air exchange sacks) in the lungs. These tiny particles bypass the lung protective system and cause inflammation in the lungs. They can also sometimes get directly into the circulation and can cause damage in the heart and other organs. According to the EPA, a large body of scientific evidence shows that exposure to fine and especially ultra fine particles can cause heart attacks, heart failure, and strokes, which results in hospital admissions, emergency department visits, and, in some cases, premature death. The scientific evidence shows exposure to fine and ultra fine particles is also likely to cause respiratory effects, including asthma attacks, reduced lung development in children, and increased respiratory symptoms such as coughing, wheezing, and shortness of breath. Prolonged exposure can cause chronic lung disease such as COPD and pulmonary fibrosis. There is more limited scientific evidence for developmental and reproductive effects, lung cancer and other cancers.
Sources of fine and ultra fine particles
Outdoor sources of fine and ultra fine particles come primarily from automobile exhausts as well as some factories. They tend to be much higher in cities, particularly inner city neighborhoods.
Indoor sources are tobacco smoke, wood burning fireplaces, gas space heaters and natural gas stoves. The way food is cooked can also produce fine and ultra fine particles. Frying in hot oil or broiling generates lots of these particles even on electric ranges. Boiling or steaming generates many fewer particles. Air fryers also generate very few particles.
Reducing Indoor Air Pollution
Natural gas is 99% methane, so burning it in a stove in addition to generating dangerous levels of NO2 and fine and ultra fine particles, is also the most potent greenhouse gas. That means that not only are gas stoves bad for your health, they are also bad for the environment. If you have a gas stove, the best option is to replace it with at electric stove with an induction cooktop. Induction cooking is much more efficient than a traditional electric burner. It uses only 60% as much electricity and heats the pot directly rather than the burner itself. Heating with induction burners are actually faster than heating with gas burners. This is of course not practical for everyone. Replacing a stove is expensive and requires an electrician to install a 220 volt outlet if you don’t have one. It is also impossible for renters. If you can’t replace your gas stove and it has a hood that vents to the outside, turn it on high every time you cook. If the hood is not vented to the outside, then opening a window helps substantially decrease NO2 and particles. Whether you have either kind of stove, using a portable air fryer is much safer than frying in hot oil on the stove. Another much less expensive option is to purchase an induction hot plate. Good ones range from 60 to 200 dollars and can plug into a regular 110 volt outlet. Induction burners only work with pots that a magnet will stick to. That includes cast iron skillets and most stainless steel cookware. Inexpensive induction compatible cookware is available at a very reasonable cost from almost all big box stores such as Walmart and Target.
Reducing Outdoor Air Pollution
There is nothing an individual can do by themselves to reduce outdoor air pollution. Working to promote affordable electric vehicles is the only long term solution for automobile exhaust pollution in cities.
Bottom Line
Chronic inflammation of the respiratory system results from air pollution both outdoors (especially in inner cities) and indoors. Smoking tobacco is also a major cause of chronic inflammation of the respiratory system. Chronic inflammation of the respiratory system leads to many chronic lung diseases as well as heart disease and possible lung cancer. Indoor air pollution is caused primarily by unvented natural gas stoves as well as gas space heaters and wood burning fireplaces. The major causes of lung inflammation are nitrogen dioxide (NO2) and fine and ultra fine particles. Indoor pollution can be mitigated by ventilation using either a hood connected to outside or opening a window while cooking. Using electric induction burners are safer and heat even more quickly than gas. Portable electric air fryers are much safer than frying in oil on any kind of stove top. Purchasing an induction hot plate is a much less expensive way to do induction cooking. Reducing outdoor air pollution requires societal change.