A new report from researchers at the University of Pennsylvania and the University at Albany, published in the peer-reviewed scientific journal Environmental Science and Technology, finds that the worst pollutants for human health are those from combustion of fossil fuels.
The research team, led by Professor Paul A. J. Amann, an assistant professor of environmental science and engineering at the Pennsylvania State University, analyzed air quality data from the United States and Canada and determined that carbon monoxide (CO) levels in the air near the city of Los Angeles increased by 7.2 percent from 2010 to 2012.
CO is a potent greenhouse gas that can have a devastating effect on the climate.
Carbon monoxide levels in Los Angeles are up by more than a third in that time period.
Amann and his colleagues looked at CO levels in air near Los Angeles from 2011 to 2012 and found that levels increased from 2010 levels by nearly 50 percent.
The CO levels rose from around the city’s central business district to areas of downtown Los Angeles.
Another study in the same study, published earlier this year in the journal Science, showed that CO levels are also up in the central business districts of Los Angles and other large cities.
Researchers looked at the CO levels of air near L.A.’s downtown business district, the city center and the downtown shopping district.
They found that the downtown area was the most polluted area in the United State.
The study also found that concentrations of particulates were up in areas with more commercial activity.
As the researchers note in their study, this study has several limitations.
First, they relied on data collected from a single, public source, which is not representative of the air quality around the country.
Second, the study focused on a small number of sources that have the highest concentrations of CO and particulates.
In other words, researchers are comparing one source to another, which limits the ability to look at air quality over a large geographic area.
Third, the researchers did not look at how the CO and pollution were measured.
The researchers did find, however, that some cities have lower CO levels than others.
The largest city in the U.S. is Seattle, with concentrations of about 100 parts per billion (ppb) in the city air.
The other largest city is New York City, with a concentration of about 70 ppb.
Fourth, the air pollution data was not based on actual measurements.
They did use measurements of CO, but they did not account for how the measurements were done.
Fifth, they did find that the levels of CO were higher in the Downtown area than in other parts of Los Angeles.
Sixth, the authors noted that the CO was more concentrated near the center of Los Angels.
Seventh, the analysis did not include other pollutants like nitrogen oxides (NOx) and volatile organic compounds (VOCs).
A report by the U of A’s Center for Environmental Health and the SUNY School of Public Health found that in the past two years, CO levels have increased in all of the five major metropolitan areas in the country, but the concentrations in Los Angelos are highest.
“It’s clear that the air in Los Angels is very polluted,” Amann said.
“The pollution is coming from a number of different sources.
We need to make sure that the communities that are in the center, that are most affected by the pollution, have access to the resources to address it.”