Why climate change and public health policy make good chemistry

A major study released today in Fresno details the direct link between higher levels of air pollution and asthma-related ER and hospital admissions. So, what’s that got to do with climate change? Plenty.

Sandy Huffaker / Getty Images

Tourists snap photos of a murky sunset in San Diego

“There’s a division in the public’s mind between global warming and health effects of pollution,” says Dimitri Stanich of the California Air Resources Board.

In reality, there’s significant overlap. Some components of air pollution shown to have harmful warming effects on the planet are also harming people, especially children, right now.

Let’s start with ground-level ozone. Ground-level ozone is different from the ozone layer, which lies about 15 miles above the earth (not exactly ground level). The ozone layer shields us from most of the sun’s harmful rays. Ozone is good in the atmosphere but bad, in many ways, at or near ground level.

Ground-level ozone is not part of air pollution itself. Instead, it is formed by a complex chemical reaction starting with the nitrogen dioxide (NO2) component of air pollution. That chemical reaction is especially strong when the air is calm and the sun is shining (California’s Central Valley in the summer, anyone?). This stuff is terrible for your lungs.

“Ozone has the same corrosive aspects of bleach,” explains Bonnie Holmes-Gen, senior policy director for the American Lung Association in California. “When people breathe it in, it damages the lining of the lungs. It’s like getting a sunburn on the lungs. It triggers coughing, wheezing and asthma attacks,”

Ground-level ozone is also a greenhouse gas. So, while it’s harming people today, it’s simultaneously helping to warm the planet. If that’s not enough, ground-level ozone’s corrosive properties harm crops, too. The Central Valley may be the nation’s salad bowl, but it’s ground zero for ground-level ozone.

Then there’s “black carbon.” If you think that sounds ominous, you’re right.Tiny particles of black carbon can lodge deep in a person’s lungs (bad) or circulate in the air and contribute to global warming (also bad). And, in a triple whammy, if black carbon particles land on arctic snow, they can accelerate the ice melt. Scientists say black carbon is a major contributor to climate change, perhaps second only to CO2. Black carbon comes from, among other things, the burning of fossil fuels, the stuff that comes from tail pipes and smokestacks.

Sunday’s New York Times featured a depressingly detailed account of Americans’ waning interest in global warming. Climate skepticism is on the rise, at least in political circles. While skepticism about the health effects of air pollution isn’t polled as much, it seems reasonable to think there’s little argument there.

This is where we get to what policymakers call “co-benefits.” Ms. Holmes-Gen points out that ground level ozone and black carbon are both fairly short-lived in the environment. “It’s a huge bang for the buck. If we reduce air pollution, we’ll see an immediate health benefit and we get warming pollutants out of the air, too.”

Lisa Aliferis is a health news editor at KQED. The complete smog & health study referred to at the top of this post is available as a PDF download from Fresno State University.

California may have great weather but also some of the nation’s worst air. The advocacy group Environment California has issued a report ranking the nation’s worst metropolitan areas for air quality. The five worst are in California, as are six of the top ten.

Craig Miller

Smog in the Los Angeles Basin

Based on data from 2010, the report’s “Top Smoggiest Areas in the US” were:

1. Riverside-San Bernardino

2. Visalia-Tulare-Porterville

3. Bakersfield (tie)

3. Los Angeles-Long Beach (tie)

5. Fresno

The report tallies 110 “smog days” for worst-ranked Riverside-San Bernardino:

“…meaning that the area, home to more than 3 million residents, had unhealthy air on one out of three days in 2010. Twenty-four of those days were categorized as “red-alert days,” meaning that air quality was so poor that anyone could experience adverse health effects…”

This is a bit like golf. In this contest, a high score is not good. Among other California contenders in the top 20, Sacramento checked in at tenth (tied with St. Louis and Knoxville, TN; and San Luis Obispo-Atascadero-Paso Robles at 17th (tied with cities in New Jersey and the Carolinas). In a separate ranking of only “large metroplitan areas,” San Diego also makes the list, and the group’s ranking of “small” metro areas includes such geographically diverse California towns as Merced (tied for 2nd) and Chico-Paradise (tied for 16th), which is tucked into the foothills of the northern Sierra.

The 61-page report uses as its benchmark the (still in place) 2008 federal ozone standard for counting “smog days.” The information is parsed and sorted into several more lists by geography, metro area size, and time frame.

One of the main constituents of smog, nitrous oxide, is also a potent greenhouse gas, which contributes to global warming.

Reed Galin

The Natural Resources Defense Council (NRDC) released an interactive tool today that maps climate-related health risks across the country, including extreme heat, poor air quality, drought, flooding, and infectious diseases. The maps present a snapshot of current health vulnerabilities using recent data at the state and county levels.

“If we stay on our present course, we can expect these health vulnerabilities from climate change to accelerate” said NRDC Senior Scientist Kim Knowlton on a conference call with reporters. “We need to prepare for the worst in extreme events and the health vulnerabilities that will result.”

According to the NRDC, one of the main health impacts Californians are facing with climate change is air pollution.  A recent report from the Public Policy Institute of California finds that two-thirds of Californians already see air pollution as a big problem.  The NRDC tool asserts that 90% of Californians live in areas that violate air quality standards, and that climate change will worsen this by bringing smoggier and hotter days.

Highlighted in red are California counties experiencing several unhealthy ozone days. Map: NRDC

The tool illustrates that the Central Valley and Southern California regions already experience several more extreme heat days each year “than expected,” and asserts that more are on the way, according to climate projections. It also plots out the state’s water crunch, which some California cities are already grappling with.

In addition to laying out the challenge, the tool also links to recommendations for adapting to increased health risks from climate change, including a section on California’s Climate Adaptation Strategy.

“We hope that our national maps will be used as a provocation for people to look and say, ‘Gee, we really need to dig in deeper,’” said Knowlton.

The tool’s data comes from a variety of sources, including the Union of Concerned Scientists, the Environmental Protection Agency, and the American Lung Association.

Los Angeles cloaked in smog shortly after sunrise. (Photo: David McNew/Getty Images)

Air pollution, already a problem for much of central and southern California, will get worse as temperatures warm, according to a new report from scientists at UC Davis and UC Berkeley.

By mid-century, trouble spots like the Central Valley and Los Angeles could experience between six and 30 more days per year when ozone concentrations exceed federal clean-air standards, depending on how much temperatures rise, and assuming that pollutant emissions in the state remain at current levels, the scientists project.

Warmer conditions cause ozone levels to increase because hotter temperatures increase emissions from automobiles and the release of gases from plants. They also increase the rate of the chemical reactions that transform the raw emissions into ozone, said the study’s lead author Mike Kleeman of UC Davis.

The authors say the study provides evidence for the ozone “climate penalty,” which refers to the extra ozone that forms as a result of climate change.

“With climate change, we get increased ozone, which can have negative health effects,” said Kleeman. “The ozone climate penalty is the extra ozone that we have to offset with additional emission controls to offset the risk to public health.”

Previous studies have made the link between climate change and increased ozone, said Kleeman, but what’s new about this report is its attention to how climate change will affect airborne particulates, another component of air pollution, and the finding that, unlike ozone, there doesn’t appear to be a clear link.

“It’s not really clear what’s going to happen with climate change and airborne particulate matter,” said Kleeman.  “We looked at temperature changes, humidity changes, wind speed changes, and precipitation changes, and it’s still not clear, but it looks like the effects on particulate matter will be small.”

This is in part due to the fact that climate change is predicted to increase average wind speeds across the state, and stronger winds  decrease particulate matter concentrations, especially along the coast.  However, Kleeman said, the study did find evidence that in the Central Valley, the worst particulate pollution days may get even more severe in the future because even though average wind speeds are expected to increase, the study results suggest that future peak concentration days may have lighter winds than they do under present conditions. Kleeman says that would worsen conditions on the extreme pollution days.

One factor contributing to airborne particulate matter that the study did not consider is fire. Wildfires are projected to intensify as the state grows warmer and drier. “It’s possible that wildfires could be the major impact of climate change on particulate air pollution in California,” said Kleeman.

The study was supported by the California Air Resources Board.

“We already know that climate change will bring us increased forest fires, shorter winters, hotter summers, and impact our water supply,” said Board chair Mary Nichols in a press release announcing the study. “Now we have scientific evidence that higher temperatures are hurting our lungs, too.”