In Santiago, Climate Change Fuels Choking Air Pollution

CREDIT: RICARDO INOSTROZA V./FLICKR
CREDIT: RICARDO INOSTROZA V./FLICKR

Thick clouds of heavy smog hung low in Santiago on Monday, a day of exceptional filth in Chile’s pollution-stricken capital city.

The haze forced more than 1,300 businesses to close after authorities declared an environmental emergency, the first of its kind since 1999. Approximately 80 percent of the city’s 1.7 million cars were forced to park, and 100 percent of the city’s 7 million people were warned to avoid outdoor activity. The warning was prudent — one of the last times this happened, an outbreak of influenza sent 3,500 children to the hospital every day.

Scientists have diagnosed Santiago with some of the “most serious air pollution problems in the world,” and the reasons amount to a perfect storm of sorts.

One is just business: The city is in the midst of an industrial boom, manufacturing everything from chemicals to textiles, which ultimately results in rising emissions. The second is location: Santiago is surrounded by mountain ranges, which trap smog in and refuse to let go.

The third reason Santiago’s pollution is so bad, though, is the most unpredictable. It’s the weather. For pollution to escape from within the clutches of the city’s mountains, it needs to rain. And though June is supposed to be one of the wettest months of the year, it is currently the driest it’s been in 47 years.

This is just one of the big threats that human-caused climate change poses to Santiago. Under a worst-case emissions scenario, rainfall is likely to drop by 10 percent in the area by 2040, and by up to 30 percent by the end of the century, according to an analysis by the Center for Global Change at Chile’s Pontificia Universidad Católica.

Less frequent rainfall means fewer opportunities for smog to escape, meaning more opportunities for prolonged pollution events that threaten the health of thousands. Of course, the effects of climate change are almost never black and white — another study predicted that, while Santiago will experience prolonged drought, precipitation events will be more extreme when they do occur, leading to flash flooding that could threaten drinking water supply.

As it happens, Santiago may be experiencing some side effects of climate change now, which may be worsening its current smog situation. Central Chile, where Santiago is located, has been in severe drought for eight years. And though it’s difficult to link specific extreme weather events to climate change, scientists have already linked this particular drought to the phenomenon, according to Reuters.

That’s bad news for the city, whose population is already experiencing a range of health problems amid frequent sitting smog. A 2014 study published in Science of the Total Environment found that airborne pollution exceeded European safety levels on three out of every four days. As airborne pollution increased, so did hospital admissions for cardiovascular disease, the Santiago Times reported.

Santiago officials have implemented measures to reduce smog. Since the city’s Atmospheric Decontamination and Prevention Plan was created in 1998, thousands of buses and trucks with inadequate pollution controls have been removed from the roads; dirt roads that sent particles flying into the air have been paved; open burning has been restricted; and regulations have been implemented to control industry emissions of sulfur oxides, nitrogen oxides, and particulate matter.

But scientists have acknowledged that this hasn’t been enough. A 2014 study found that little had been done to reduce the major component of particulate matter in the city — soil particles.

In Santiago, the study found, a lot of pollution comes when very dry soil particles fly away from construction sites and dirt roads, picking up and transporting other chemical compounds with it. Frequent rainfall, the study said, likely helps make sure the soil particles don’t become dry enough to blow around.

As climate change worsens, however, frequent rainfall is becoming less likely in the region. Indeed, Chile’s President Michelle Bachelet is treating the current drought as permanent.

“Faced with this critical situation,” she said in March, “there is no choice but to assume that the lack of water resources is a reality that is here to stay.”