Heat and extreme drought have worsened smog in California over the last year, stalling decades of progress toward cleaner air and increasing health risks.
state's prolonged dry spells have brought more temperature inversions,
with a layer of warmer air trapping cooler air below, concentrating
pollution near the ground. Mother Nature could clear away much of the
bad air with rain or wind, but high-pressure systems have resulted in
fewer storms, less circulation and unusually stagnant conditions.
a steady trend of air quality getting better, but layered on top of
that is the meteorology, which is a crazy, up-and-down thing that is
very hard to predict," said Anthony Wexler, director of the Air Quality
Research Center at UC Davis.
Relief could come as soon as this winter — if enough storms blow in to stir up the air and sweep out pollution.
say a weak El Niño has a 58% chance of developing in the Pacific Ocean
this winter and could bring more rain to California, cleansing the air.
absent an El Niño, if we can just get back to a normal winter, air
quality will be significantly better," said Seyed Sadredin, who heads
the San Joaquin Valley Air Pollution Control District.
winter, the district recorded the worst air pollution in more than a
decade. And last week, the valley's fine-particle pollution again jumped
to unhealthful levels.
Many Californians have experienced the
jump in pollution as more hazy vistas and bad air days. Others have
faced noticeable health consequences.
"You see it, and for
someone who has breathing problems, you feel it," said Pati Calzada, 27,
a college student who lives in the Inland Empire city of Colton, one of
the smoggiest areas in the nation.
Both Calzada and her
7-year-old son, Abraham, who was recently diagnosed with asthma, have
trouble breathing when pollution levels go up.
"It feels like a
weight on my chest, and I know I'm not the only one," she said. Her
frustration with polluted air led her to join a Sierra Club campaign to
advocate for solar power and other clean energy.
worse, in part, because higher temperatures accelerate the chemical
reactions that form ozone, the lung-damaging ingredient in warm-weather
smog. In a vicious circle, heat also boosts demand for electricity,
increasing smog-forming emissions from power plants.
conditions also have led to increasing numbers of California wildfires,
which release more smoke. And dry farmland has been kicking more dust
into the air.
There's a steady trend of air quality getting better,
but layered on top of that is the meteorology, which is a crazy,
up-and-down thing that is very hard to predict. - Anthony Wexler,
director of the Air Quality Research Center at UC Davis
drought caused air pollution to increase across California last winter,
conditions were worst in the San Joaquin Valley. Fine particles jumped
to their highest concentrations since 2001, more than three times the
federal standard of 35 micrograms per cubic meter.
The troubles continued this fall, as the valley and Southern California reported more bad air days from ozone.
unusual spell of high temperatures and a strong inversion layer hit the
San Joaquin Valley last week, causing fine-particle pollution to build
up to dangerous levels. The region's air quality officials are telling
residents to stop burning wood and reduce their driving. Activists have
called for school sporting events to be canceled to protect children's
Though air pollution is a year-round problem in California, it peaks in two distinct seasons.
the summer, ozone is the main pollutant of concern. It is not emitted
directly but formed after cars, trucks, power plants and factories
release reactive gases and unburned hydrocarbons. Those pollutants cook
in heat and sunlight to form ozone, a corrosive gas.
ozone can harm children's lungs, trigger respiratory problems such as
asthma and bronchitis and worsen heart and lung disease. On days with
high ozone pollution, hospital visits for asthma rise and the risk of
premature deaths increases.
In winter, another type of air pollution called fine particulate matter, or soot, becomes the main problem.
particles emitted by diesel engines, fires and other combustion sources
measure less than 1/30th the width of a human hair. They are of great
concern to health experts because they are inhaled deep into the lungs
and can impair breathing and damage the heart and blood vessels.
exposure to fine particles is linked to thousands of premature deaths a
year in California, mostly from heart attacks and cardiovascular
disease. Most of those fatalities occur in Southern California, where a
2010 economic study found that fine-particle pollution contributes to as
many early deaths as traffic accidents.
Pollution regulators have downplayed the recent uptick in smog as a blip in a decades-long trend of improving air quality.
ozone concentrations in Southern California are down to about one-third
of what they were in the 1970s and '80s. The region's fine-particle
pollution has been cut in half since measurements began in 1999.
from cars, trucks, ships, power plants and industrial facilities are
falling because of local, state and federal regulations that ensure the
air will keep getting cleaner in the long term, regulators say.
Still, California is far from meeting air quality standards.
meet a 2032 deadline to comply with current standards, the South Coast
Air Quality Management District will have to slash smog-forming gases,
called nitrogen oxides, more than 75%, regulators say.
that level will require near-zero emissions across much of the economy.
And in the long term, rising temperatures from climate change will make
controlling smog more difficult, posing new challenges in the district,
which includes 16.7 million people in Los Angeles, Orange, Riverside and
San Bernardino counties.
The San Joaquin Valley faces similar
obstacles. Air quality officials say new rules adopted this year place
the valley under the nation's most stringent wood-burning restrictions,
virtually banning the use of traditional fireplaces during the winter
season to control a major source of lung-damaging soot.