Smoke From Camp Fire Making Sacramento the Most Polluted City on Earth

November 16, 2018, 5:40 PM EST

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Above: Mattelin Bautista and Stephen Penner don masks to deal with the smoke from the Camp Fire that shrouds the state Capitol Thursday, Nov. 15, 2018, in Sacramento, Calif. Smoke from the blaze that burned through the Butte County city of Paradise is creating a health hazard that experts say could lead to an increase in serious health problems, especially for children and the elderly. (AP Photo/Rich Pedroncelli).

Smoke from California’s Camp Fire has settled into Central California’s valleys and cities and refuses to leave, like a bad case of bronchitis one simply can’t shake. On Friday, the pollution became so severe that all schools in the San Francisco Bay area were closed, including area colleges, and the city’s iconic cable cars were taken out of service. The state capitol, Sacramento, also closed all of its schools. This is a rare and extremely dangerous air pollution episode, and I’m not familiar with a case where a major U.S. city shut down all of its schools for wildfire smoke. A Berkeley Earth website that tracks global pollution levels has consistenly shown Sacramento, California as having the worst air pollution for any major city on Earth over the past day, beating out the big cities in India and China that usually hold that position.

Smoke on Nov 15
Figure 1. Smoke from the Camp Fire had settled in over much of Central California, including the San Francisco Bay area, as seen on Thursday afternoon, November 15, 2018, in this MODIS image. Image credit: NASA.

On Thursday at EPA’s monitor in downtown San Francisco at 10 Arkansas Street, the 24-hour PM2.5 level was 145 μg/m3. That’s about four times higher than the 24-hour standard of 35 μg/m3, and well into the purple “Very Unhealthy” air regime. In EPA’s on-line records that extend back to 1999, the previous highest 24-hour PM2.5 levels measured in San Francisco were 76.6 μg/min 2001.

In Sacramento, the pollution was even more dire: the 24-hour PM2.5 levels on Thursday were 263 μg/m3. That’s about seven times higher than the 24-hour PM2.5 standard of 35 μg/m3, and lies in the maroon “Hazardous” range—the highest level of danger on EPA’s Air Quality Index (AQI) scale. At this level, EPA warns that “this would trigger a health warnings of emergency conditions.” I’m not familiar with a past case of a major U.S. city experiencing a “Hazardous” air quality reading for 24-hour PM2.5 levels from wildfire smoke.

A high death toll likely from the smoke

The direct death toll from the Camp Fire that devastated Paradise, California was upped to 63 on Thursday evening, with over 600 people still missing. Unfortunately, the indirect deaths from this disaster are likely to far exceed the direct deaths, given the large population that is being exposed to dangerous levels of choking smoke. A July 2018 paper by Colorado State's Bonne Ford and co-authors estimated that wildfire smoke contributed to 17,000 premature air pollution deaths per year, on average, in the U.S. in the year 2000. This number was projected to rise to 44,000 deaths per year by the year 2100, if we follow a “business-as-usual” approach to climate change (RCP8.5 scenario), which would lead to a steady increase in U.S. wildfires.  A premature air pollution-related death typically occurs about twelve years earlier than it otherwise might have.

Figure 2. The Air Quality Index (AQI) from wildfire smoke for fine particulate pollution (PM2.5) was in the red “Unhealthy” range (AQI above 150) or purple “Very Unhealthy” range (AQI above 200) over much of California on Friday morning. Six stations near Sacramento reported maroon “Hazardous” conditions (AQI above 300). Image credit: EPA.

Dangerous air pollution to continue through Tuesday

Light winds are expected over most of California’s smoke-affected areas through Saturday, keeping the air pollution levels dangerously high. On Sunday, a developing upper-level low pressure system will drive more of an onshore flow of air from the ocean, which may cause a modest reduction in the smoke near the coast. True relief from the smoke, however, will likely not occur until Wednesday or Thursday next week, when a major Pacific storm system is expected to move into California, potentially bringing the state its first significant rain of November.

I’ll have a new post on Hurricane Michael’s storm surge this afternoon.

Bob Henson contributed to this post.

The Weather Company’s primary journalistic mission is to report on breaking weather news, the environment and the importance of science to our lives. This story does not necessarily represent the position of our parent company, IBM.

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Dr. Jeff Masters

Dr. Jeff Masters co-founded Weather Underground in 1995 while working on his Ph.D. in air pollution meteorology at the University of Michigan. He worked for the NOAA Hurricane Hunters from 1986-1990 as a flight meteorologist.

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