A rise in wildfires in the drought-plagued U.S. West may significantly degrade air quality and create health problems, researchers say. More numerous wildfires not only pose an immediate threat to people's safety and homes but also could take a long-term toll on human health, agriculture and ecosystems, scientists at Penn State report in the journal Environmental Science & Technology. Investigating possible future climate scenarios, ecosystem scientist Matthew D. Hurteau and his colleagues estimated that by 2100, emissions from wildfires in California would grow by 19 percent to 101 percent above the baseline period (1961-1990.) The largest emissions increases concentrated in Northern California, they reported. An increase in wildfires will mean significant societal challenges, they said, such as higher pollution levels that can affect human health and aggravate respiratory conditions. Poor air quality can lower crop yield and forest health could suffer, they said.