Is air quality better by the sea?

The below article talks about the air quality, the factors that affect air quality by the sea, carbon sequestration, ocean acidification, along with some frequently asked questions about air quality along the coast. 

Is air quality better by the sea?

The answer to this question is unfortunately not quite simple. The general characteristics for oceans to be able to act as carbon sinks and in general, due to wind directions and pressure conditions that promote movement from higher-pressure areas to lower pressure areas, pollutants do tend to be swept into the mainland causing coastal areas to have better air quality than mainland areas. However, various recent studies have been disputing these claims; with some reporting that seasides have higher pollutant concentrations because of conflicting environmental conditions or due to anthropological activities. 

Oceans as Carbon Sinks 

A carbon sink refers to any element that has the capability of absorbing carbon from the atmosphere, in quantities more than what it emits annually. With respect to this definition, a carbon sink can be anything from soil, plants, trees, to oceans. A carbon source refers to any element that releases more carbon than what it absorbs, such as vehicular emissions, burning of fossil fuels, volcanoes, emissions from extractive industries, etc. Carbon sinks are of two types:

  • Natural such as the oceans, forests, trees, etc.
  • Artificially induced carbon sinks such as certain technologies or chemicals 

Oceans cover up to 70% of the earth’s surface and play an important role in absorbing atmospheric CO2. Research shows us that the ocean is capable of absorbing up to 25% of emissions from anthropological activities, every year. It is estimated that oceans take up billions of tonnes of CO2 from the atmosphere, and this is one of the largest reasons that humanity does not see a more severe impact of climate change from all the anthropological activity that is conducted globally. Therefore, oceans are able to act as buffers that drastically reduce the impacts of global warming on the planet. 

Carbon sinks are crucial to reducing the impacts of climate change, and this is the reason why researchers have been trying to figure out artificial methods to do the same. However, the efficiency of these artificially created systems has been questioned by several actors and these systems have been found to not be able to withstand extreme temperatures. It has been found that in some systems, there seemed to be carbon leakage from these systems as well, therefore reducing their efficiency in carbon sequestration. The largest disadvantage to natural carbon sinks is that they have a limit to absorbing atmospheric carbon. For example, in oceans when the limit is crossed, it causes ocean acidification which has drastic impacts on marine ecosystems and decreases the pH of water, leading to lasting implications to human health as well. 

Ocean Acidification

Post the industrial revolution, carbon emissions into the atmosphere have increased drastically, creating a lasting impact on air quality and climate change. At this time, NOAA has reported that the pH of the ocean has reduced by 0.1 pH units, which may not look like much but denotes that ocean acidity has increased by 30% (NOAA, 2020). 

CO2 that is naturally present in our atmosphere is able to dissolve into the ocean water and it comes to form carbonic acid. This acid is capable of dissociating into hydrogen ions and bicarbonate ions. The increase in hydrogen ions causes the ocean to turn acidic. Current pH readings of the ocean indicate a level of 8.1, which means it’s alkaline or basic in nature. But as anthropological activities increase, so does the CO2 which moves into the ocean, causing eventual ocean acidity. 

From the atmosphereWater that absorbs atmospheric carbonCarbonic acidFree hydrogen ionsBicarbonate ions

Ocean acidification has severe impacts on the marine ecosystem, such as oysters, coral reefs, etc. Species that make hard shells and skeletons through calcium and carbonate in seawater are threatened for survival due to ocean acidification. As excess hydrogens are formed due to ocean acidification, it combines with the available carbonate in the water, which reduces the amount of carbonate available for these species to make their shells, maintain their skeletons, and threatens the integrity of the coral reef structures. As the pH moves into the acidic range, these shells and skeletons will disintegrate, therefore, threatening the habitats of millions of marine species.

Air Quality in Coastal communities

It is no surprise that the world’s coastal communities have been taken over due to rapid globalization and urbanization, by larger companies and shipping magnates to create ports for importing and exporting goods. A study conducted at the University of Calgary seemed to report that the air quality caused by the shipping industry could be magnified when combined with prevailing weather conditions, especially during extreme temperatures and poor air circulation. 

This phenomenon has reportedly increased the ground-level concentrations of ozone and other particulate matter. Professor Hans Osthoff of the University of Calgary was quoted the following:

“We found unexpectedly high levels of certain air pollutants where pollution from cities and ships meets salt in the ocean air along the southeast coast of the United States. It only makes sense that this is a problem everywhere industrial pollution meets the ocean, as is the case in many of the largest cities around the world. It also changes our view of the chemical transformations that occur in ship engine exhaust plumes, and tells us that emissions from marine vessels may be polluting the globe to a greater extent than currently estimated.”

With respect to previously believed concepts of air being cleaner by the sea, it can be thus concluded that air quality is in fact deteriorating along coastlines, especially with respect to rapid economic development that is unsustainable in nature, leaving chronic and devastating impacts on land and marine ecosystems. It is therefore important for state and global actors to band together to form initiatives that reduce their global emissions. This would be a crucial step to improving air quality and reducing the vulnerability of coastal communities from bearing the brunt of severe ocean acidification and large-scale air pollution. 

These initiatives could be a stepping stone for many global importing and exporting companies to create sustainable competitive advantages over their competitors and would ensure that they are able to continue their services in a holistic and environment-friendly manner. This increases their reputation amongst global and national actors and gives them a sustainable and strong foothold in the growing financial and economic markets. 

Improving outdoor air quality

It is within the reach of our responsibilities to improve outdoor air quality. Some measures that could be taken would be as follows:

  • Encouraging citizens to make the switch to electric vehicles as studies have shown that partially reducing vehicular emissions does not have enough impact, and to completely get rid of the nitrogen oxide pollutants, we need to completely make the shift to electric vehicle systems.
  • Provide subsidies and tax cut-offs to larger polluters to switch to cleaner sources of fuel.
  • Enforce the polluter pays principle where the largest contributors to the air quality are fined for its destructive practices. 
  • Planting more trees in an effort to create a carbon sink to reduce the temperatures in the area. 
  • Take large-scale climate actions to address the community’s needs and meet global commitments such as the Sustainable Development Goals (SDGs). 
  • Reduce the emissions of volatile organic compounds (VOCs) from all sources, regardless of the size or the degree of impact. This could mean that the city could ban the usage of high VOC paints, chemicals, cleaning solutions, hairsprays, air fresheners, chemical solvents, etc. This would be key to ensuring that ozone levels are below the recommended levels. 
  • Reduce emissions from industries and other primary small-scale sources such as incinerators or burning of raw fuel sources and waste. 
  • Enforce strict health standards and air quality regulations on relevant stakeholders, and ensure there is increased accountability between them through efficient and continuous monitoring and evaluation of these standards.
  • Conduct effective and periodical monitoring of the programs implemented to ensure that they are relevant to the circumstances at hand and that they can be modified to meet the demands at the time. 
  • Increase participation and accountability between stakeholders at all levels and beneficiaries to ensure that a participatory approach is used to address community issues and that it is inculcated into any strategy that may be implemented. 

Frequently Asked Questions (FAQs): Is air quality better by the sea?

How do I know what the different numbers and colors mean in an AQI?

Sourced from The Air Quality Index Scale as defined by the US Environmental Protection Agency (US EPA):

AQIPollution LevelHealth ImplicationsCautionary Statement 
0 – 50GoodAir quality is considered satisfactory, and air pollution poses little or no riskNone
51 -100ModerateAir quality is acceptable; however, for some pollutants, there may be a moderate health concern for a very small number of people who are unusually sensitive to air pollution.Vulnerable and at-risk children and adults, people with respiratory diseases, such as asthma, should limit prolonged outdoor exertion.
101-150Unhealthy for Sensitive GroupsMembers of sensitive groups may experience health effects. The general public is not likely to be affected.Vulnerable and at-risk children and adults, and people with respiratory diseases, such as asthma, should avoid outdoor exertion.
151-200UnhealthyEveryone may begin to experience health effects; members of sensitive groups may experience more serious health effectsActive children and adults, and people with respiratory disease, such as asthma, should avoid outdoor exertion; everyone else, especially children, should limit prolonged outdoor exertion
201-300Very UnhealthyHealth warnings of emergency conditions. The entire population is more likely to be affected.Active children and adults, and people with respiratory disease, such as asthma, should avoid all outdoor exertion; everyone else, especially children, should limit outdoor exertion.
300+HazardousEmergency Health Alert: everyone has a higher vulnerability to experience more serious health effectsEveryone should avoid all outdoor exertion

How do forests and trees absorb carbon?

Forests and all elements in them are capable of absorbing carbon in a phenomenon called carbon sequestration which is done through photosynthesis, where plants and soil absorb atmospheric carbon, store them, and return oxygen to the atmosphere. 

Other FAQs about Air Quality that you may be interested in.

Is Fresno Air Quality Good?

Is LA Smog good or bad?

How can you improve indoor air quality?


ClientEarth. (2020, December 22). What is a carbon sink? ClientEarth Communications. Viewed on 12-16-2021.  

Hewson E. W. & Olsson L. E. (2012, March 16). Lake effects on air pollution dispersion. Journal of the Air Pollution Control Association. 17(11). pp. 757 – 761.  

National Oceanic and Atmospheric Administration (NOAA). (2020, April 1). Ocean Acidification. Viewed on 12-15-2021. 

Shutler J. & Watson A. (2020, October 1). The oceans are absorbing more carbon than previously thought. World Economic Forum. Viewed on 12-16-2021. 

Sustainability for all. (n.d.). What are carbon sinks? Acciona. Viewed on 12-15-2021. 

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