While the northern regions of the US spend their winters fighting through snow storms and the coldest conditions of the year, many warmer climate US cities that suffer from pollution issues typically see nicer air quality in the winter months. This winter has been very different, however, for residents of California's Central Valley. Due to dry conditions in December and January, air has stagnated across California, with the situation the most dire in the area stretching from Modesto to Bakersfield, where air quality has fallen well below national health standards for more than a month.
According to air quality officials, air quality in the San Joaquin Valley in recent weeks has been the worst in over a decade. Making matters worse, it's the most dangerous kind of poor air, laced with microscopic, chemical-laden particles that can get into people's lungs and create health issues in even the healthiest people. The area stretching between Stockton and Bakersfield is home to about 4 million people and typically records the highest level of particulate matter and ozone pollution in the country. The area boasts an asthma rate that is a full 3 times higher than the national average.
As a result of this pollution, most of the communities in this area have enacted fireplace burn bans, which air quality advocates are insufficient because they ignore other major sources of pollution like dairies, feed lots and oil rigs. At the same time, the San Francisco Bay Area is also experiencing its worst pollution in years. According to the San Francisco Chronicle, local authorities have declared so-called “Spare the Air” days, in which air quality is unsafe, a total of 12 times since the beginning of November.
Clean air advocates have criticized the Central Valley Air Quality Coalition and its policies calling them ineffective. But officials have claimed that their policies are sound, but there is little they can do with La Nina conditions in the Pacific creating stagnant air. The Central Valley's pollution woes stem from its geographical positioning. The area is surrounded by three sides by mountains, and where the valley opens toward San Francisco in the north, weather patterns suck the emissions from the massive motropolitan area south into the valley, creating unsafe, stagnant air conditions.