The smell of sea salt at the beach is a pleasant thought for many beach goers. Wind and waves kick up spray sending salt (sodium chloride into the air. Most salt of this sort falls back into the sea or nearby beach. The bit of chloride lingering in the air can react with nitrogen oxides (NOx) to form nitryl chloride which is a forerunner of chlorine gas, the most reactive form of chlorine. Those gas can contribute to smog formation in coastal areas.

However, in a surprise, researchers have found that this air chemistry thought to be restricted to sea spray occurs at similar rates in the air above Boulder, Colorado which is nearly 900 miles away from any ocean. What’s more, local air quality measurements taken in a number of national parks across the United States imply similar conditions in or near other non-coastal metropolitan areas.