Airborne Algae: A Rising Public Health Risk

Abstract

H armful algal blooms (HABs) are known to produce toxins that threaten human and animal health.Absorption of HAB toxins through the skin and ingestion can cause health risks such as dermatitis and respiratory allergies, 1 but the inhalation of these toxins remains an understudied threat.Considering the recent global pandemic driven by aerosol-based transmission of SARS-CoV-2, new developments in science and policy should prioritize the health impacts of air quality and composition.These air quality considerations must expand past viruses and other welldocumented primary biological atmospheric particles to include the rising public health risk from airborne HAB toxins and consider policies focused on research, education, and regulatory action.Currently, airborne HAB species and toxins are the least-studied organisms in both aerobiological and phycological (the scientific study of algae) studies. 2 HABs occur when aquatic photosynthetic organisms, primarily cyanobacteria, dinoflagellates, and diatoms, grow rampant, use up the oxygen in the water, and produce toxins. 1 HABs can be caused by increasing water temperatures, stagnant water, and a high concentration of nutrients (phosphorus and nitrogen) caused by fertilizer runoffs. 3eople can be exposed to HAB toxins through skin contact, ingesting contaminated water, consuming food with HAB toxins, and inhaling airborne droplets that contain toxins. 3mportantly, reports have shown increased sensitivity to inhaled toxins compared to ingestion. 2These toxins can range from dermatoxins (like aplysiatoxin and lyngbyatoxin-a) that impact the skin, hepatotoxins (such as microcystin, anabaenopeptin, and nodularin) and cytotoxins (like cylindrospermopsins) that damage the liver and other internal organs, and neurotoxins that affect the central nervous system. 3,4Some HAB neurotoxins, such as β-N-methylamino-L-alanine (BMAA), 5 are suggested to have a role in certain cases of Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis (ALS). 6Given the potential severity of these toxins, states like Florida that are especially at risk for HABs regularly monitor their waters for both the toxins and the species that produce them. 7While HABs and their toxins are monitored in water, the levels of algae and toxins in the air, within aerosols, are not.Aerosols, commonly associated with the fine mist of perfume or paint, are sprayed suspensions of particles released from

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