In general, certain particulate and gaseous contaminants released into the air can contribute to increased exposure when inhaled at higher concentrations and/or for prolonged periods over time. For some people, inhalation of these contaminants can aggravate symptoms of allergies; chronic lung diseases, such as asthma and cystic fibrosis; and chronic obstructive pulmonary disease (COPD), which includes emphysema and chronic bronchitis. Excessive exposure to the contaminants can also help initiate other health conditions.Nitrogen oxide gases — like those detected leaking from gas stoves in some studies — also can irritate the respiratory system in high concentrations, further aggravating lung conditions. These gases also affect the environment by contributing to acid rain and other atmospheric pollution.Methane gas from gas stoves doesn’t directly expose the user and is not associated with any specific health concerns. However, it’s a contributor to climate change. Methane is more than 25 times as potent as the carbon dioxide emissions that come from our cars, even though it’s more short-lived than carbon dioxide. That’s why the EPA and other environmental organizations have prioritized reductions in methane emissions — concentrations of methane over the years have swiftly multiplied, but because it’s so potent and simultaneously short-lived, reducing methane could have a big effect on reducing global warming. The recent study of gases leaking from gas-fueled stoves noted the release of methane even when the stoves aren’t being used.Carbon monoxide gas, similar to the creation of smoke and particulate matter, results from incomplete or inefficient gas fuel combustion. When generated through the burning of natural gas, carbon monoxide, like other contaminants mentioned, may accumulate in rooms with inadequate ventilation. Unlike the other contaminants, excessive accumulation and concentrations of the odorless carbon monoxide can contribute to carbon monoxide poisoning and even become deadly within hours.Particulate matter from combustion consists mainly of various carbon-based products and may contribute to short-term irritation of the respiratory system and a range of other potential inflammatory impacts. The main contributor to the generation of particulate matter during cooking/baking is smoke. Toxicity hazard is influenced by both the chemistry of the particulate matter and the size of the particles, which are measured in microns. (One micron is about 1/25,000th of an inch.) Particulate matter less than 10 microns in diameter is more able to be breathed into the lungs. Even smaller sizes (for example, less than 2.5 microns) can travel even deeper into the respiratory system. Ultrafine particulate matter (smaller than 1.0 micron) can potentially move from the lungs into the general circulation.