How Environmental Exposures Actually Get Into Your Body
Every day, your body encounters small exposures you might not even notice, through the air you breathe, the food and water you consume, the things that touch your skin, and even the devices and electrical systems around you. Most of us don’t face one big “toxic event.” Instead, small exposures quietly accumulate over time, adding to what your body has to process on an ongoing basis.
Scientists call these “exposure pathways,” which is just a fancy way of describing the different routes things from our environment can take into our bodies. The purpose of this article is to help you understand these pathways and how everyday things in your home can interact with multiple systems in your body over time, often in ways that are easy to miss because there’s no single obvious moment of exposure. If you’ve been doing everything right and still feel like something is off, this is probably the piece nobody has pointed you toward yet.
There are five primary exposure pathways relevant to your home environment: inhalation, ingestion, dermal absorption, direct entry, and energetic. The first four involve physical substances. The fifth is different, and we’ll get to why that matters.
Inhalation
Every time you breathe, you’re not just taking in oxygen and filling up your lungs. You could also be inhaling tiny particles, gases, or chemicals that your lungs and bloodstream then have to process such as mold fragments and mycotoxins, VOCs (i.e. released from paint, furniture or cleaning products), combustion byproducts from gas appliances or fireplaces, and actual particles called “fine particulate matter” from sources both inside and outside your home.
Most people assume that if they can’t smell anything, the air is fine. That’s not how it works. Your lungs have millions of tiny air sacs designed to rapidly exchange oxygen and airborne chemicals and particles can enter your bloodstream and reach your brain and organs quickly. Unlike ingestion which you’ll read about below, inhalation bypasses the digestive system’s filtering process entirely (i.e. your stomach) and go directly from the lungs into the bloodstream, circulate throughout the body, and ultimately reach the liver for processing.
Because you’re breathing continuously, even low levels of indoor air pollution create ongoing demand on your body which is why indoor air quality is worth paying attention to separately from outdoor air quality. You can’t always assume one reflects the other, and for most people, the air inside their home is the air they’re breathing most consistently and it’s usually two to five times more polluted than outside.
Quick stats: An example of the impact of indoor air quality, there was a research project in Seattle called the Breathe Easy Project looked at whether improving indoor air quality could influence health outcomes for children with asthma. Sixty homes were built with HEPA filters, filtered fresh-air intake, lower off-gassing building materials, and moisture control. When researchers from the University of Washington and Public Health Seattle and King County compared families in their old housing with those in the specially designed homes, children with asthma had an average of 12.4 symptom-free days per two weeks compared with 8.6 in their previous homes, and urgent asthma-related clinic visits dropped from 62 percent to 21 percent over a three-month period. Families also reported fewer sleepless nights and lower medical costs.
Ingestion
Ingestion happens whenever you eat, drink, brush your teeth, cook, basically when something is swallowed, it passes through the digestive tract and is sent to the liver before circulating elsewhere in the body. This is called first-pass metabolism, and it means anything you swallow reaches your liver first.
Research shows roughly 70 to 75 percent of many orally consumed chemicals are processed by the liver before they reach the rest of the body, creating an ongoing burden on both the gut and liver when exposures are consistent over time.
Water is one of the more significant ingestion pathways from a home environment perspective because tap water quality varies depending on your source, your location, your plumbing, and what’s making its way through the system. A U.S. study published in January 2025 examined PFAS, per and polyfluoroalkyl substances, in drinking water and found that in counties with detectable PFAS, certain cancers were up to 33 percent more common than in counties without detectable PFAS. A separate 2025 study in Southern California found that people living in areas with PFAS in drinking water had 32 percent higher levels of a related compound in their blood than those in areas without detectable PFAS, indicating that PFAS from water can accumulate in the body even at low levels.
Quick stats: Common patterns researchers associate with long-term ingestion exposure include digestive changes such as bloating, irregular bowel movements, and new food sensitivities, as well as persistent fatigue, thyroid changes, and brain fog.
Most ingestion exposure doesn’t come from a single dramatic event but accumulates over time.
Dermal Absorption
Your skin is not a sealed barrier. Many substances can dissolve into skin oils and pass through the outer layers into circulation, a process called dermal absorption. This happens during showering and bathing, handwashing, cleaning, personal care product use, and contact with treated fabrics and furnishings. Warm water and steam increase skin permeability, making absorption more likely during everyday routines.
This is the pathway that surprises people most, especially those who have already switched to cleaner personal care products.
Quick stats: A study published in the Journal of Exposure Science and Environmental Epidemiology in 2021 looked at women’s exposure to phthalates, a class of chemicals commonly used in personal care products, lotions, shampoos, and fragrances. Women who used more phthalate-containing products had significantly higher levels of these chemicals in their bodies, with the most exposed group showing two to three times higher phthalate metabolite levels than the least exposed group. A 2022 study found that people living in homes with higher levels of formaldehyde off-gassing had higher circulating levels of related biomarkers in their blood, suggesting that skin contact and inhalation combined contributed to the total picture.
Because dermal absorption bypasses digestion, toxins can enter circulation more directly than things you swallow. Researchers commonly associate long-term dermal exposure with skin signals like dryness, irritation, rashes, and increased sensitivity to products, as well as thyroid changes, persistent low energy, and generalized inflammation.
Dermal absorption is one of the sneakier pathways because it isn’t an obvious exposure like eating or drinking. It happens through the ordinary routines of daily life.
Injection
Injection happens when something punctures the skin such as a sliver or a needle, but it can also include medical injections, IVs, contaminated medical devices. Unlike the other pathways, injection bypasses your body’s natural filtering systems entirely. Whatever enters goes straight into the bloodstream or tissues with no filtering step and the body can respond with acute (immediate) inflammation or an immune response.
This pathway is less frequent in everyday life than the others, but it’s worth understanding because it illustrates what your natural barriers are doing all the time. Your skin, lungs, and digestive system are constantly filtering on your behalf. When those defenses are bypassed, the body has to respond immediately and without a buffer.
EMFs: A Different Kind of Exposure
Electromagnetic fields, or EMFs, don’t fit into the first four pathways because they’re not a substance at all. They’re a form of energy, and that distinction matters for understanding how they interact with your body and why they can be very confusing.
EMFs come from everyday sources in your home: Wi-Fi routers, cell phones, household wiring, and appliances. They’re present in every home and, like most of the exposures we’ve covered, they’re largely invisible. You can’t smell them, taste them, or feel them making their way into your body, which is part of why they stay off the radar. Most people’s first reaction is skepticism, which is fair. But the mechanism isn’t mystical, it’s electrical, and your body runs on electricity.
Because EMFs are energy rather than a chemical or particle, they can’t be inhaled, ingested, or absorbed through the skin the way other exposures can. Instead, they pass through the body and interact with its own electrical signaling systems. Your brain, nervous system, heart, and muscles all rely on tiny electrical impulses to function, and EMFs operate in that same space.
Research published in peer-reviewed journals including PubMed has looked at several mechanisms. EMFs can affect voltage-gated calcium channels, which help regulate cell activity and stress responses and can increase reactive oxygen species, unstable molecules that contribute to oxidative stress and inflammation. Studies also show that EMFs, particularly from screens and wireless devices at night, can interfere with melatonin production. A 2022 study found that people in higher nighttime EMF exposure environments had up to 30 percent lower melatonin levels, linked to poorer sleep quality and increased fatigue.
Researchers commonly associate long-term EMF exposure with difficulty falling or staying asleep, non-restorative sleep, persistent fatigue, brain fog, anxiety, and increased sensitivity to other environmental stressors.
Why This Matters
Your home contributes to all five of these exposure pathways simultaneously, and that’s the part most people have never been told to think about. If you sleep fine on holiday but struggle at home, or you feel better on weekends when you’re away from your usual environment, it’s worth taking a look at your environment.
You can be doing a lot of things right and still be missing this piece entirely, not because you haven’t tried hard enough, but because nobody maps all five pathways back to the place you spend the most time.
The home is where the exposures stack. And stacking is what makes the difference between a body that’s coping and one that isn’t.
If you’d like some free guidance on where to start with your own home environment, I offer a free call to make sure you’re pointed in the right direction. You can schedule with me here.
