Answer: The burning of natural gas associated with oil extraction
Notes: Recent aircraft-collected samples of natural gas flares in the USA reveal significant variations in nitrogen oxides emissions. Gas flaring, burning associated with oil extraction, persists due to safety, but is wasteful and polluting. Lack of infrastructure or financial incentives leads firms to flare when unable to bring associated gas to market. Most flared gas is similar to natural gas, requiring processing to remove contaminants. Associated gas can be used on-site or converted using gas-to-liquid technologies for various applications.
