The science of smoke

How and why air pollution affects both man and machine

By Soncirey Mitchell
Reader Staff

Bonner County was able to avoid the summer haze for quite a while; but, recently, a cloud of smoke blowing in from eastern Washington and beyond has blanketed the area. Itchy eyes and sore throats are the least of our worries when it comes to smoke’s effects on our bodies, ecosystem and vital electronics.

The visible particles in smoke are soot, char and ash, which seem synonymous for most laypeople. Actually, soot is composed of carbon-rich, ultrafine particles, while char is partially combusted organic matter with many chemical byproducts. Ash is the mineral residue left over after everything else has burned.

Smoke’s chemical makeup depends on three main factors: what’s burning, how hot it is and how it’s put out. Off-gassing from fires, combined with smoke’s mixture of fine and ultrafine particles, can create hydrochloric acid, hydrobromic acid, hydrofluoric acid, sulfuric acid, nitric acid and phosphoric acid — especially in lower-temperature, smoldering blazes. Forest fires in particular often burn hot and so contain higher levels of pollutants like carbon monoxide and volatile organic compounds.

Electronics

Whether basic or acidic, the compounds in smoke quickly corrode metal, glass and plastic, leaving tiny scratches or pits in the material. This is an aesthetic nuisance for things like car clear coats, but it’s far more severe when it infiltrates complex machines. Smoke can short-out or destroy circuit boards, create incorrect readings in sensitive medical equipment and even cause elevator mechanisms to break down. Smoke’s grit also gets between moving parts like car brakes, reducing stopping power, and clogs filters and cooling systems, causing computers, refrigerators and most other large electronics to overheat.

Plants

Biologists and ecologists agree that the effects of smoke on vegetation require far more study, and current findings are often contradictory. Studies on crops like corn and soybeans have shown smoke to have both positive and negative effects, due to its particles’ ability to reflect sunlight.

Reflecting sunlight into the atmosphere makes it harder for plants to photosynthesize and grow. The smoke’s volatile organic compounds can also mix with sunlight and nitrogen oxides to create ground-level ozone, which damages plant tissue during respiration. 

According to an article in The Conversation, research conducted on ponderosa pines in Colorado found that, when exposed to smoke, the trees effectively “held their breath.” The pines stopped photosynthesizing, shutting down the exchange of oxygen and carbon dioxide. Researchers did not conclude whether this was because smoke residue clogged the trees’ pores or if the pores closed to keep out the smoke, though it’s likely a combination.

However, smoke can scatter sunlight, allowing it to hit plants at different angles and therefore reach previously shaded leaves. This can actually increase photosynthesis and drought tolerance because it keeps plants cooler and reduces transpiration (water evaporation through the plant cells).

Animals (that’s us)

Many animals that die in wildfires perish not from the flames, but from asphyxiation. Research conducted by the University of Washington and published in 2022 confirmed that smoke’s harmful effects on humans are also reflected in wildlife. Terrestrial and aquatic animals exposed to smoke can develop “carbon monoxide poisoning, respiratory distress, neurological impairment, respiratory and cardiovascular disease, oxidative stress and immunosuppression.” Essentially, the pollutants in the smoke infiltrate both the lungs and the bloodstream, traveling into the heart, nervous system and beyond. The toxins also damage lung tissue, leading to low oxygen and high carbon dioxide levels in the blood, and these issues can have lasting impacts on overall health. According to the National Wildlife Federation, young rhesus macaque monkeys exposed to smoke develop reduced lung capacity and weakened immune responses for years.

Stanford University professors researching the effects of wildfire smoke in 2025 said that it is “about 10 times as toxic as the regular air pollution from the burning of fossil fuels.” According to experts, there is no safe amount to breathe in — especially for children — and wildlife smoke inhalation actually accounts for about 500 deaths annually.

As of press time, the air quality index listed Sandpoint at “moderate,” with particles small enough to enter the bloodstream. Though it’s not as dangerous as it has been in recent weeks, remember to limit time spent outside and keep indoor spaces sealed with air purifiers running, if possible. Your lungs will thank you.