Most people don’t think about their home as a place where exposures accumulate, and I didn’t either, for a long time. Maybe you already think about what you eat, what you put on your skin, or what’s in your water if you’re already paying attention to those things. But the home as a whole, as an environment that’s continuously interacting with your body, that’s usually not part of the conversation.

That’s what I’m going to walk you through here.

Scientists use the term “exposure pathways” to describe the different routes things from our environment can take into our bodies. It’s a technical phrase for something that’s actually straightforward once you see it laid out. And once you do, it can change how you think about your home.

The five pathways are inhalation, ingestion, dermal absorption, injection, and electromagnetic. The first four involve physical substances. The fifth is different, and I’ll explain why that matters.

Inhalation

Every time you breathe, you’re not just taking in oxygen. You could also be inhaling tiny particles, gases, or chemicals that your lungs and bloodstream then have to process. These can include mold fragments, fumes from paint, furniture, or cleaning products, gas appliances, and other tiny particles from sources both inside and outside your home.

Most people assume that if they can’t smell anything, the air is fine, but that’s not how it works.

Here’s why inhalation matters as a pathway: your lungs are designed to move things into your bloodstream quickly and efficiently. That’s their job. This means when you breathe in toxins, they don’t stay in your lungs. Thy enter your bloodstream and can reach your brain and organs faster than other routes and bypasses the digestive system’s filtering process entirely. Things go directly from your lungs into your bloodstream, circulate throughout your body, and ultimately reach your liver for processing.

Because you’re breathing continuously, even low levels of indoor air pollution create ongoing demand on your body. That’s why indoor air quality is worth paying attention to separately from outdoor air quality. You can’t assume one reflects the other. For most people, the air inside their home is the air they’re breathing most consistently, and research consistently shows indoor air is often two to five times more polluted than outdoor air.

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. Children with asthma in the improved homes 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 three months. Families also reported fewer sleepless nights and lower medical costs. That’s a meaningful shift from changes most people would consider manageable.

Ingestion

Ingestion is exactly what it sounds like: anything you swallow. That includes food and drinks, but also things you might not think about, like water for brushing your teeth, residue on unwashed produce, or anything that makes its way into your mouth during cooking or cleaning.

Anything you swallow passes through the digestive tract and reaches the liver before circulating elsewhere in the body. Your liver is essentially the first organ to process anything you consume, and when exposures are consistent over time, that creates an ongoing burden that’s easy to overlook because it builds so gradually.

Water is significant because the quality of tap water can vary and depend on the source of the waTer, your location, your plumbing, and what’s making its way through the system. A study published in January 2025 examined PFAS, a class of synthetic chemicals found in many water supplies, in drinking water and found that in counties with detectable PFAS, certain cancers were up to 33 percent more common than in counties without. 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 even low-level exposure can accumulate in the body over time.

Most ingestion exposure doesn’t come from a single event. It builds quietly, which is exactly why it’s worth understanding.

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. In plain terms, this means things you put on your skin, or that your skin comes into contact with, can make their way into your body.

This happens when you shower or take a bath, wash your hands, use personal care products, or touch fabrics and furnishings that have been treated with chemicals. Warm water and steam increase skin permeability, meaning it’s easier for your skin to absorb making this more likely during everyday routines you may not think twice about.

This is the pathway that surprises people most, especially if you’ve already switched to cleaner personal care products. And I understand why, because swapping products feels like a meaningful step. But the fabrics on your bed, the water in your shower, and the cleaning products you use every week are still part of this picture.

A study published in the Journal of Exposure Science and Environmental Epidemiology in 2021 looked at women’s exposure to phthalates, chemicals commonly found in personal care products, lotions, shampoos, and fragrances. Women who used more phthalate-containing products had two to three times higher phthalate metabolite levels in their bodies 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, substances can enter circulation more directly than things you swallow. It’s one of the less obvious pathways because it usually happens through ordinary, daily routines, not through a single event.

Injection

Injection happens when something punctures the skin directly, a sliver, a splinter, a needle, or contaminated medical devices. It’s less common in everyday home life than the other pathways, but it’s worth understanding because of what it illustrates.

Unlike the other pathways, injection bypasses your body’s natural filtering systems entirely. Whatever enters goes straight into the bloodstream or tissues without a filtering step, and the body has to respond immediately. Your skin, lungs, and digestive system are constantly working as barriers on your behalf. When that’s bypassed, even briefly, there’s no buffer between the exposure and your bloodstream.

EMFs: A Different Kind of Exposure

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.

EMF stands for electromagnetic field. These fields come from everyday sources in your home: your electricity and household wiring, Wi-Fi routers, cell phones, and appliances. They’re present in every home and, like most of the exposures we’ve covered, largely invisible. You can’t smell them, taste them, or feel them entering your body, which is part of why they stay off the radar.

Most people’s first reaction is skepticism, but it isn’t mystical. It’s electrical, and your body communicates via electrical signals. Your brain, nervous system, heart, and muscles all rely on tiny electrical impulses to function.

Because EMFs are energy rather than a chemical or particle, they can pass through the body and interact with its own electrical signaling systems rather than being inhaled, ingested, or absorbed through the skin. Research published in peer-reviewed journals has looked at several mechanisms. EMFs can affect voltage-gated calcium channels, which are essentially the switches that help regulate cell activity and stress responses. They can also increase reactive oxygen species, unstable molecules that contribute to oxidative stress, which is a kind of internal pressure your cells have to manage. Studies also show that EMFs, can affect the body’s endocrine system, nervous system, melatonin production, inflammation, and stress response, to name a few. 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.

Why This Matters

Your home contributes to all five of these pathways simultaneously, and that’s the part most people have never been told to consider.

You can be doing a lot of things right and still be missing this piece, not because you haven’t tried hard enough, but because nobody has mapped these pathways back to the place you spend the most time. If you sleep better when you’re away from home, or you feel noticeably different in other environments, your home environment is worth a closer look.

Understanding the pathways is the first step. Knowing which ones are most relevant to your specific home and how you live in it is where the real clarity comes from. If you’d like help with that, I offer a free call to make sure you’re pointed in the right direction. You can schedule with me here.