On collecting the mice several weeks later, Araujo made a troubling discovery: The mice exposed to freeway air presented a terrible blood profile. Their HDL, the so-called good cholesterol, had been rendered dysfunctional.
The ultrafine particles in polluted air, he posited, "could be undermining so much of the progress we've made in this area."
The epidemiological community has long worried about the effect of smog on the lungs. But research on the health effects of bad air is now expanding, and the news is not good.
Smog, it turns out, can have devastating effects not just on lungs but on hearts, brains and fetal development.
Work coming out of Mexico City, increasingly L.A.'s sister city in the environmental sciences, has documented how amyloid plaque, one of two suspect brain proteins associated with Alzheimer's, increases with exposure to air particles, especially in children and young adults. Research originating at UCLA and USC shows how ultrafine particles, or UFP, initiate the so-called inflammatory cascade that leads not only to brain diseases but asthma and chronic obstructive pulmonary disease.
New research in environmental pediatrics has demonstrated a consistent, dose-dependent relationship between expectant mothers living in high-emissions-adjacent housing and premature births, low birth weights, birth defects and respiratory diseases. In a recent report, the UCLA Institute of the Environment concluded that the problems were of such magnitude as to "require drastic changes to motor vehicle and transportation systems" over the next decades.
USC scholars are blazing new paths as well. Over the last 20 years, they have invented ways to concentrate particles from the freeway, assess their specific toxicity in human doses and then test various hypotheses with lab animals genetically engineered to physiologically respond like humans. They can even track real-time daily human exposures to ultrafine particles.
On any given day in Los Angeles, mobile smog units are out measuring how pollution ebbs and flows on a neighborhood-by-neighborhood basis. Research subjects wear "personal ambient pollution" backpacks to track how individuals experience different loads of smog throughout their day, part of which may be spent in a low-pollution environment, part in a high. Through modern genomics, we also now know that several highly prevalent gene mutations make some people more susceptible to pollution, and that others make them less susceptible.
What -- besides moving to Fargo -- can we do? A few recent successes are heartening, among them new regulations on truck exhaust and improvements to filtering systems used by schools that are near freeways. And, as usual, public health officials are working to increase awareness and advocating for new regulations and funds for more research.
But we need to go further. Every person in Southern California should be able to find out what the "inflammatory load" is in their neighborhood; they also should know where the region's "emissions hot spots" are located. (One way might be to amend this newspaper's weather page to include readings of ultrafine particles within the critical 1,500 feet of major motorways.) And we need an independent counterpart to the Southern California Air Quality Management District, one charged with implementing breakthrough science to mitigate the effect of ultrafine particles on health.
As was the case in the city's first war on smog about half a century ago, there will be resistance to this new body of science because it brings unwelcome news. Industry will hate any new regulations. Some solutions will surely upend traditional political alliances, pitting affordable-housing advocates, for example, against those advocating environmental justice.
With leadership, Los Angeles can find a way to reconcile those interests. It did so 40 years ago, and it can do so now. An increasingly hazy world is waiting.