How Ocean Air Quality Impacts Coastal Cities

by Amanda Hawkins

You know the feeling when you breathe in fresh ocean air? The warm, salty breeze is often associated with health benefits. After all, it does usually smell fresher.

But is air quality actually abetter by the ocean?

What do we know really about ocean air? In today’s blog, we’ll talk about ocean air quality, and more specifically, how the ocean air impacts coastal cities.

Is Air Quality Better by the Ocean?

While the air near the ocean can be cleaner than in other areas, that’s not always the case. When we dump sewage and other pollutants into the water, it significantly impacts the coastal air quality.

In fact, one recent air quality study found that pathogens from waste in the ocean can transfer to the air and be found several miles inland—which is what we’re highlighting today.

Recent Research Findings on Ocean Air Quality

A study published by researchers from the Scripps Institution of Oceanography looked at the ocean air quality in an area south of San Diego near the US-Mexico border. In Mexico, near that area, a wastewater treatment plant regularly dumps sewage into the Tijuana river, then flows north into Imperial Beach.

And the result of that?

In 2022, Imperial Beach closed for 249 days due to high levels of pathogens like salmonella, norovirus and E. coli, as a direct result of the sewage. While researchers know the potential harms related to these pathogens, little was previously known about the impact of these pathogens on air quality.

During this study, researchers sampled water from the Tijuana river and coastal aerosols (particles suspended in the air) at Imperial Beach for 26 days in 2019. They then used DNA sequencing to match bacteria and chemical compounds between these locations.

They found that approximately three-quarters of the bacteria found in aerosols at Imperial Beach came directly from the sewage in the surf zone.

Additionally, researchers found these pathogens a mile or two inland from Imperial Beach. Plus, there is evidence that winds can blow coastal spray hundreds of miles inland.

Prather says, “We don’t know what the effect is yet of inhaling this cocktail that comes out of the ocean – it’s something we are trying to understand.” The research will continue in this area to increase our understanding of the potential impacts of these pathogens on ocean air quality and the risks to our health.

How Ocean Spray Affects Air Quality

When waves break, approximately 20% of the bacteria present in the water break off and bubble into the air. Prather describes this as a “hydrophobic goo that doesn’t like water, so it will almost float like oil on the surface of the ocean.”

So, when waves crash and the bubbles burst, that material launches into the air. This ocean spray then directly impacts the ocean air quality. Storms also contribute to the amount of raw sewage and other pollutants released into our waterways.

If the surf is high and there’s lots of white foam, the conditions are perfect for bacteria in the water to transfer to the air easily.

5 Common Pollutants in Ocean Air Spray

Ocean air spray contains several pollutants from various sources. Some common pollutants found in ocean air spray are:

• E. coli
• Salmonella
• Norovirus
• Heavy metals
• Other chemicals such as pesticides

This new air quality study provides evidence that pollutants in the ocean do transfer to the air and impact ocean air quality for coastal cities. However, more research is necessary to fully understand the impacts when these pollutants, particularly those from sewage, are breathed in.

Worried about your air quality?

Monitor the Particulate Matter levels around the world with our free, real-time PurpleAir Map or join PurpleAir’s mission to make air quality data accessible to everyone by investing in an air quality monitor for your home.

Together, we can be informed and make changes in our daily habits and the community to improve air quality.