California’s restrictions on vehicle emissions have been so effective that in at least one urban area, Los Angeles, the most concerning source of dangerous aerosol pollution may well be trees and other green plants, according to a new study by University of California, Berkeley, chemists.
California’s restrictions on vehicle emissions have been so effective that in at least one urban area, Los Angeles, the most concerning source of dangerous aerosol pollution may well be trees and other green plants, according to a new study by University of California, Berkeley, chemists.
Aerosols — particles of hydrocarbons referred to as PM2.5 because they are smaller than 2.5 microns in diameter and easily lodge in the lungs — are proven to cause cardiovascular and respiratory problems.
As a result of strict vehicle emissions laws, organic aerosol levels have been significantly reduced throughout the United States, but the drop has been particularly dramatic in Los Angeles, which started out at a higher level.
Read more at: University of California - Berkeley
In 2018, organic aerosols made up about 23% of the aerosol pollutants in Los Angeles (blue on pie chart), a large portion of which is due to chemicals emitted by plants. The right chart shows how aerosol concentrations in LA have declined over time, leveling out around 2012. (Photo Credit: UC Berkeley graphics by Clara Nussbaumer and Ronald Cohen)
