by Emily Atkin THINK PROGRESS

Despite humanity’s best interest, the ongoing hubbub about vaccines is not going away. For that, at least partially, you can thank those parents who still believe the Measles, Mumps, and Rubella (MMR) shot can cause autism.

While that belief has been frustrating — particularly for those exposed to the country’s growing measles outbreak — many have pointed out that those parents are, at the very least, well-meaning. The only reason they’re not vaccinating is because they want to prevent their child from what can sometimes be a difficult disorder.

The problem, of course, is that there isn’t any science to back up that well-intentioned concern. But fear not, benevolent ones: there is a scientifically valid cause you can get behind if you want to reduce the risk of autism, and it doesn’t mean potentially exposing anyone to measles. It’s environmentalism.

Yes, environmentalism, the ideology that life is improved by cleaner air, land, and water. You see, while the cause of autism is still unknown, most scientists believe that it is influenced by a combination of genetic and environmental factors, particularly the exposure to heavy metals like mercury. Genetics are pretty hard to change; comparatively, the quality of our environment is not.

As it turns out, the science linking pollution to increased autism risk is growing. In fact, just around the time the U.S. began its descent into what is now a large multi-state measles outbreak, scientists from the Harvard School of Public Health published new peer-reviewed research in the journal Environmental Health Perspectives — the first nationwide study examining the link between air pollution and autism.

The study, which took ten years to complete, focused on 245 children with autism and 1,522 children without it, all with mothers who did not move after giving birth. That way, the researchers could track exposure to pollution before, during, and after pregnancy. (A really great description of the study’s full methodology can be found here, from Emily Gertz at TakePart).

Using air quality data from the U.S. Environmental Protection Agency, and taking into account how far away the mothers lived from highways, power plants, etc., the scientists found mothers exposed to pollution before or after pregnancy only seemed to be weakly associated with autism risk. But while pregnant, mothers who were exposed to high levels of fine particle pollution (PM2.5) — particularly in the third trimester — had a greater-than-normal odds of her child having autism.

“We are confident saying that air pollution is a risk factor for autism,” Michael Rosanoff, director of public health research at the group Autism Speaks, told Gertz. Rosanoff’s group helped fund the study.

The Harvard study is the latest, but certainly not the only, study linking PM2.5 pollution to autism risk (which, it should be noted, is not the same as saying pollution causes autism. It’s just that the statistical risk is increased. The science is not yet there for causation). A study published last year found a significant association between autism and “harmful environmental factors.” In 2012, University of Southern California researchers found that California children exposed to more air pollution had higher rates of autism.

The science is not perfect. As Laura Blue noted in a piece exploring the autism-pollution link for Time magazine, the studies do not imply causation, which “ultimately raise as many questions as they answer,” she writes. “It’s not clear how or why the chemicals we breathe may affect development and autism risk, for example, although the researchers suggest that pollutants may impact both neurological development and inflammation, which can damage the lining of blood vessels in the brain and compromise the blood-brain barrier.”

Still, the body of research linking autism risk to air pollution is astoundingly more robust than the literal non-body of research linking it to vaccines. And PM2.5 — the tiny particles found in smoke and haze and emitted from power plants, cars, and other industries — is already known to be harmful in many other ways. Because the particles are so small, the EPA says they can penetrate the deepest parts of the lungs, triggering respiratory and cardiopulmonary problems. PM2.5 also contributes to visible pollution haze and acid rain.

So if you really want to fight something that might increase children’s risk of autism, fight for tighter regulation on power plant emissions. Rally for ozone and smog reductions, buy an electric car, advocate for renewable energy and clean infrastructure. Become an environmentalist.

But for God’s sake, vaccinate your children.