COVID-19 lockdowns made stark changes to Earth’s air pollution. In the early stages of the pandemic, people started noticing drastically clearer skies as pollution and smog decreased due to stalled production and fewer vehicles on the road. One team of researchers decided to use this to their advantage and study air pollution in the second-most populous city in the US: Los Angeles (LA), California.
Ammonia is a dangerous air pollutant often produced by vehicles. It’s hard to determine how much ammonia is produced by cars versus other significant sources, like agriculture. But when COVID-19 surged and LA went into lockdown, estimates say traffic decreased 24%. LA is known for its outrageous traffic, so this noticeable decrease gave researchers a unique opportunity to study vehicle emissions in the region.
LA was chosen because of its air pollution problem. Researchers observed that downtown LA (which has a lot of car traffic), and Riverside, California, which hosts many livestock and agriculture farms, were two major hotspots. While farms were thought to have been the most significant contributors to ammonia pollution, this study’s results say otherwise.
A new study published in Environmental Science & Technology Letters found that the ammonia levels from cars may be significantly higher than national averages suggest. State and national surveys estimate that ammonia emissions from vehicles make up 13-22% of total ammonia pollution, while researchers calculated that it is possible cars could contribute to upwards of 60-95%.
This study was the first time that ammonia levels from vehicles were able to be studied via satellite. In the first half of March 2020, researchers collected data from the western half of LA and created computer models to turn satellite images into quantitative data on ammonia levels.
Next, the team wants to expand this research to other cities using the same techniques. It’s estimated that 15,000 premature deaths are caused by ammonia pollution in the US per year, but these estimates, like previous estimates of ammonia levels, may be higher than we thought. These researchers hope that their results will reveal the dangers of underestimating ammonia pollution and hopefully lead to more regulations for vehicles.
Source: Environmental Technology and Letters, BBC
