A new survey released on Wednesday found that the Los Angeles wildfires took an extraordinary financial and emotional toll on millions of people in Southern California that extended far beyond the communities that burned.

More than 40 percent of the adults surveyed said they knew someone who had been personally affected by the wildfires that began on Jan. 7. The polling equivalent of more than a million adults said the fires had directly cost them jobs or income. And about a third of respondents said they had donned masks to protect themselves from the smoke hazards.

The survey, by the Luskin School of Public Affairs at the University of California, Los Angeles, underscored the extent to which the fires transcended the vastness of Southern California, where even large-scale disruptions can often be swallowed up by the region’s sheer size.

Los Angeles County, the nation’s most populous at about 9.7 million residents, stretches for more than 4,000 square miles, encompassing 88 cities and about a quarter of the state’s population. The two main January fires — in Pacific Palisades on the Pacific Coast and in Altadena to the east, at the base of the San Gabriel Mountains — were more than 34 miles apart.

But as hurricane-force winds whipped up one inferno after another, claiming 30 lives and destroying thousands of buildings, the threat of the disaster seemed to stretch countywide. The survey found that even in relatively unscathed places 20 miles or more from the fires, like the suburbs on the Palos Verdes Peninsula and in northern areas of the county, roughly a quarter of respondents said they knew someone who had lost a home or a business.