Air quality tests show improvement immediately following freeway closure

California works hard to keep air pollution down. That’s why cars are smog checked, incentives are offered to hybrid drivers and legislators are fighting to build a high-speed rail in the state. Regardless, Californians are dependent upon their cars. For Los Angeles to shut down part of its freeway system near Santa Monica is to cause uproar known as Carmaggedon.

The car apocalypse has happened before at about the same time of year. The same stretch of the 405 freeway was shut down last year as part of a multi-billion dollar project to improve a key stretch of roadway. The first Carmeggedon was highly anticipated by residents who feared the city would come to a screeching halt. Area airports offered flights between them in order to avoid the freeway traffic.

After last year went fairly smoothly, there was less fear for this year’s freeway closure. A new study released regarding the previous Carmaggedon shows that the freeway closure may have been a blessing for Los Angeles air quality. Tests during the closure when no cars ran through the 405 segment that was closed showed almost no discernible signs of ultrafine particles.

What’s even more impressive about the findings is that the presence of these particles dropped by a full 83 percent within ten minutes of the closure. Larger particles were taken down by 36 percent. Overall, the valley affected by the 405, which includes Santa Monica and West Los Angeles, had an air quality improvement of 75 percent during the freeway closure. The entire region of Los Angeles spanning from Long Beach to Ventura experienced a 25 percent improvement in air quality thanks to the temporary drop in freeway traffic.

Traditionally, Los Angeles has some of the worst air quality in the country. Unfortunately, the freeway closure’s effect was only temporary and the air pollution levels were back to average once cars were running through the 405 again. However, the immediate drop in pollution by taking out a single section of freeway impressed scientists. Future air quality could be far better than it is today if people continue to search for alternatives beyond the gas-guzzling combustible engine.