BY AUSTIN PERLMUTTER, MD

First—thank you, Uber. As a frequent user of your services, I sincerely appreciate the convenience you provide.

You’ve helped me get home to my family, stay efficient on work trips, and navigate situations that would otherwise have left me lost, stressed, and disoriented.

I know you care about creating a pleasant environment for passengers. Air fresheners and scented products seem like an easy, straightforward way to do that—whether it’s a plug-in diffuser or a pine-tree-shaped freshener hanging from the mirror.

As a passenger, I value the attention you give to creating a clean, welcoming ride.

Yet, as a physician and researcher focused on environmental health, I must raise a concern—and a clear recommendation: please consider removing air fresheners from your vehicles.

The Hidden Problem with Air Fresheners

No one wants to breathe unpleasant odors—especially in the close quarters of a car.

Air fresheners, with names like “Ocean Breeze,” “Sunset Beach,” “Autumn Spice,” and “Forest,” promise to mask bad smells while creating a relaxing atmosphere.

But behind these pleasant scents are poorly regulated chemicals that get released into the air and may last for weeks—raising the risk of various health issues ranging from low testosterone and migraine headaches to cognitive impairment and cancer.

Research has shown that air fresheners often emit toxic compounds that can produce secondary pollutants, including ultrafine particles, free radicals, and formaldehyde—among the most widely recognized cancer-causing agents.

Yet manufacturers are not required to disclose most of the ingredients in these products. This lack of transparency is particularly concerning because pollutant concentrations can become very high in small, enclosed spaces like vehicles.

The United States Consumer Product Safety Commission, which oversees air fresheners, does not require manufacturers to disclose their ingredients—leaving consumers and healthcare providers to seek out information and stay current with the research.

So, what does the research tell us? A comprehensive 2020 study published in Air Quality, Atmosphere, & Health tested twelve common car air fresheners—including sprays, vent clips, and hanging ornaments—and detected 546 VOC emissions representing 275 distinct chemicals.

Among these, nine were classified as potentially hazardous under US and international safety frameworks.

Even more striking: air fresheners marketed as “natural,” “green,” and “organic” were no safer than conventional versions—emitting carcinogenic compounds in types and concentrations similar to regular brands.

Of the hundreds of chemicals detected, fewer than ten percent appeared on any product label or safety data sheet—and none of the hazardous compounds were disclosed.

The study authors note:

Air fresheners are pervasive within indoor environments, from public and private buildings to forms of transportation. Although air fresheners may be used with the intent to enhance environments, studies reveal that these products generally impair rather than improve indoor air quality…

Sources of exposure include not only privately owned vehicles, but also publicly available vehicles such as rental cars, rideshares like uber, and taxi cabs. Within the confined space in cars, exposures may be of particular concern, both for the driver and passengers.

Air freshener exposures have been associated with a range of adverse health effects, including asthma symptoms, breathing difficulties, migraine headaches, and dizziness.

Reducing risks from air freshener exposures is vital not only for occupant health but also for public safety. Further, air freshener chemicals can continue to be emitted within interior spaces, such as within cars, even after the air fresheners are removed.

Health Risks to Drivers and Passengers

Survey data report that about thirty-five percent of the population—roughly 120 million Americans—report significant health challenges when exposed to air fresheners and other fragranced products. Children are particularly at risk.

Because kids breathe more air per pound of body weight than adults, they are especially vulnerable to airborne pollutants. Their lungs, immune systems, and brains are still developing, making them susceptible to toxins that trigger inflammation and oxidative stress—processes known to harm cognitive function and disrupt healthy development.

A 2024 systematic review of forty studies published in Developmental Cognitive Neuroscience found that air pollution in children is associated with:

• Reduced brain volume in several regions

• Smaller corpus callosum—the bridge between brain hemispheres

• Lower levels of brain-derived neurotrophic factor (BDNF)—crucial for learning and memory

These biological changes translate into real-world consequences, including lower IQ, higher rates of ADHD, and an increased lifetime risk of depression.

Given that children spend over ninety percent of their time indoors—including in cars, schools, and at home—the quality of indoor air they breathe is critical.

Protecting developing brains starts with cleaner air: regularly changing cabin air filters, improving ventilation, and avoiding unnecessary chemical exposures such as fragranced air fresheners.

These risks extend to drivers as well—the majority of whom are men. Many synthetic fragrances contain chemicals classified as endocrine disruptors, which can interfere with hormone function.

In men, such exposures can affect testosterone production and balance, impacting energy levels, libido, mood, and overall vitality.

Considering the long hours drivers spend in small, enclosed spaces, repeated exposure to these chemicals can have cumulative effects over time—making cleaner, fragrance-free air not just a comfort issue, but a workplace safety priority.

Fresh Air–Healthier Alternatives

If the goal is a clean, pleasant ride and relaxing atmosphere, there are healthier options Uber and others can use:

• Change out your car air filters: Many (maybe even most) of us forget that our cars have air filters that need to be regularly changed. Replace your filter every 12,000 to 15,000 miles—or roughly once a year—to more effectively filter your vehicle’s air.

• Regular Cleaning: Regularly vacuuming seats, carpets, and mats, and wiping down surfaces with fragrance-free cleaners helps eliminate odors at their source. Shampooing and steam cleaning upholstery can also help.
  
  Keep in mind, many automotive shampoos contain added fragrances or chemical solvents that can leave behind VOC residues. As such, opt for fragrance-free or plant-powered products to avoid replacing one source of indoor pollution with another.

• Ventilation: When you’re not in heavy traffic or passing through tunnels, consider cracking the windows to help dilute and flush out pollutants trapped in the cabin. Even a small window opening can significantly reduce VOC and particulate matter levels.
  
  If you’re parked, opening opposite windows creates cross-ventilation, moving stale air out more efficiently. On the road, using your car’s “fresh air” setting (instead of recirculation) can help bring in cleaner outside air—especially important after using cleaning products, transporting pets, or carrying items with strong odors.

• Maintain the HVAC system: Have the heating and cooling system inspected regularly. Mold or mildew can grow in vents and ducts, especially in humid climates, and contribute to musty odors.

• Use natural odor absorbers: Baking soda sprinkled overnight on seats or carpets (then vacuumed) neutralizes odors. A bowl of white vinegar left in the car for a few hours can also help—just be sure to air out the vehicle afterward. Additionally, activated charcoal is a natural, scent-free odor absorber—small bags can be placed under seats or in cup holders.

You work hard to give passengers a safe, comfortable ride. Choosing non-toxic solutions over chemical fragrances helps protect your health as well as theirs.

Uber Workplace Safety

Uber has been a key player in innovating and implementing rideshare safety measures for both passengers and drivers.

From thorough driver background checks to in-app features like trip sharing, emergency buttons, and 24/7 support, these initiatives demonstrate a commitment to creating a safer rideshare experience.

Going fragrance-free would be a natural extension of that safety leadership. Just as physical safety measures help guard against immediate dangers, reducing exposure to unnecessary chemical pollutants protects riders and drivers from health risks that may be less visible but no less significant.

A clean, scent-free cabin enhances the overall safety of the rideshare environment, creating conditions that promote comfort and a secure, enjoyable journey for everyone on board.

I should add that clean air in rideshares is a shared responsibility. Just as drivers can help by avoiding air fresheners, passengers can be considerate by limiting the use of strong perfumes, colognes, or artificial scented body products before rides.

These fragrances can linger in the enclosed cabin, contributing to air quality issues for drivers and future passengers.

Driving Toward a Healthier Future

I urge Uber to take the next bold step in protecting the well being of its community: adopt a company-wide fragrance-free policy for all rides. This simple, cost-free change would not only reduce avoidable health risks but also demonstrate Uber’s continued commitment to innovation and leadership in safety.

By making fragrance-free rides the standard, Uber can set a new benchmark for rideshare health standards—ensuring every trip is as safe, healthy, and comfortable as it is convenient.

Passengers can play a vital role in this change. When you notice an air freshener in the rideshare, consider saying something as simple as, “Would you mind if I opened the window a little?”

This small gesture can create immediate relief from chemical scents and start an important conversation about air quality. Each respectful exchange helps build understanding and moves us closer to a rideshare environment where clean air and shared health are the standard for every ride.

Thank you,
Dr. Austin Perlmutter

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Austin Perlmutter, MD, is a board-certified internal medicine physician, New York Times bestselling author, researcher, educator, podcaster and entrepreneur.

His mission is to help people get their brains unstuck for better mental and cognitive health. Dr. Perlmutter’s work on how environment and diet influences brain health has been featured on PBS, Rolling Stone, Newsweek, NPR, Fox, CBS, and other top media outlets.

He has co-produced and hosted some of the world’s largest online brain health events including Alzheimer’s, the Science of Prevention and the Better Brain Blueprint. He is the Managing Director of Big Bold Health, where he led a pioneering study exploring plant nutrient effects on human aging. He is the CEO of Lichen Air, which provides science-backed indoor air solutions for better brain health and longevity. He is also a research consultant to the Helfgott Research Institute, where he studies the epigenetic, metabolic, microbiome and immune effects of ayahuasca.

REFERENCES

Steinemann A, Nematollahi N, Weinberg JL, et al. “Volatile chemical emissions from car air fresheners.” Air Quality, Atmosphere & Health, 2020: 1-6.

Joseph G Allen, Piers MacNaughton, Usha Satish, et al. “Associations of Cognitive Function Scores with Carbon Dioxide, Ventilation, and Volatile Organic Compound Exposures in Office Workers: A Controlled Exposure Study of Green and Conventional Office Environments,” Environ Health Perspect. 2016 Jun;124(6):805-12.

Anna M Parenteau, Sally Hang, Johnna R Swartz, et al. “Clearing the air: A systematic review of studies on air pollution and childhood brain outcomes to mobilize policy change,” Dev Cogn Neurosci. 2024 Oct:69:101436.

Anne Steinemann. “Ten questions concerning air fresheners and indoor built environments,” Build & Enviro. 2017 Jan: 279-284.