Chemicals

When wildfire smoke is in the air, doctors urge people to stay indoors to avoid breathing in harmful particles and gases. But what happens to trees and other plants that can’t escape from the smoke? They respond a bit like us, it turns out: Some trees essentially shut their windows and doors and hold their breath. As atmospheric and chemical scientists, we study the air quality and ecological effects of wildfire smoke and other pollutants. In a study that started quite by accident when smoke overwhelmed our research site in Colorado, we were able to watch in real time how the leaves of living pine trees responded. How plants breathe Plants have pores on the surface of their leaves called stomata. These pores are much like our mouths, except that while we inhale oxygen and exhale carbon dioxide, plants inhale carbon dioxide and exhale oxygen. A highly magnified view of stomata in a maize leaf. Umberto Salvagnin/Fli...

The wildfires that burned across Maui, Hawaii, in August 2023 became the deadliest conflagration in the United States in more than a century. While the harm to homes and tourism drew the most attention, agriculture was also heavily affected across the island, and the harm did not stop once the flames were out. In some cases, fires smoldered underground for weeks. Water systems were destroyed, and some were contaminated in ways scientists are only beginning to understand. Two weeks after the Maui fires began, they were still smoldering below ground. Andrew Whelton/Purdue University, CC BY-ND As an environmental engineer, I work with communities affected by wildfires and other disasters. I also led a team of university and public works professionals to assist in Maui’s response to the fires. In a new study based on that effort, my team worked with the Hawaii Department of Agriculture to assess d...

Chemists invented PFAS in the 1930s to make life easier: Nonstick pans, waterproof clothing, grease-resistant food packaging and stain-resistant carpet were all made possible by PFAS. But in recent years, the growing number of health risks found to be connected to these chemicals has become increasingly alarming. PFAS – perfluoroalkyl and polyfluoroalkyl substances – are now either suspected or known to contribute to thyroid disease, elevated cholesterol, liver damage and cancer, among other health issues. They can be found in the blood of most Americans and in many drinking water systems, which is why the Environmental Protection Agency in April 2024 finalized the first enforceable federal limits for six types of PFAS in drinking water systems. The limits – between 4 and 10 parts per trillion for PFOS, PFOA, PFHxS, PFNA and GenX – are less than a drop of water in a thousand Olympic-sized swimming pools, which speaks to the chemicals’ toxicity. The...

The more scientists learn about the health risks of PFAS, found in everything from nonstick cookware to carpets to ski wax, the more concerning these “forever chemicals” become. The U.S. Environmental Protection Agency now believes there is no safe level for two common PFAS – PFOA and PFOS – in drinking water, and it acknowledges that very low concentrations of other PFAS present human health risks. The agency issued the first legally enforceable national drinking water standards for five common types of PFAS chemicals, as well as PFAS mixtures, on April 10, 2024. I study PFAS as an environmental health scientist. Here’s a quick look at the risks these chemicals pose and efforts to regulate them. What exactly are PFAS? PFAS stands for per- and polyfluoroalkyl substances. This is a large group of human-made chemicals – currently estimated to be nearly 15,000 individual chemical compounds – that are used widely in consumer products and i...

PFAS, the “forever chemicals” that have been raising health concerns across the country, are not just a problem in drinking water. As these chemicals leach out of failing septic systems and landfills and wash off airport runways and farm fields, they can end up in streams that ultimately discharge into ocean ecosystems where fish, dolphins, manatees, sharks and other marine species live. We study the risks from these persistent pollutants in coastal environments as environmental analytical chemists at Florida International University’s Institute of the Environment. Because PFAS can enter the food chain and accumulate in marine plants and animals, including fish that humans eat, the spread of these chemicals has ecological and human health implications. Biscayne Bay and nearby coastal areas are teeming with fish, including many varieties that people eat. NPS image by Shaun Wolfe I...