BETHLEHEM, Pa. — Fine particulate air pollution in the Lehigh Valley exceeds World Health Organization standards, but the lowest concentrations are in residential areas removed from highways, according to a $100,000 regional air monitoring project.
While none of the air monitoring locations so far evaluated exceeded the United States’ standard for a daily average of PM 2.5 concentrations, all but one of the sites measured are nearly double the World Health Organization’s stricter guidelines, researchers behind the Lehigh Valley Breathes project said in its latest update.
Released in mid-November, it builds on the previous update, comparing the data collected over a month last year at eight monitoring locations to existing regulatory standards in the United States, as well as the air quality guidelines recommended by the WHO.
“Although PM 2.5 pollution standards have been strengthened many times based on evolving science, even at low levels of exposure, this pollution poses serious harm to human health."Lehigh Valley Breathes
“There is an additional reason for concern about local air quality despite the apparent compliance with regulatory standards,” officials said.
“Although PM 2.5 pollution standards have been strengthened many times based on evolving science, even at low levels of exposure, this pollution poses serious harm to human health.
“This is why groups such as the American Heart Association question whether there is any ‘safe’ level of exposure, and why organizations such as the World Health Organization recommend setting standards that are stronger than those set by the U.S. and many other countries.”
This is the second analysis released since data collection was finalized in late August, and it represents only a small portion of the total data collected.
Additional analyses are planned to be released ahead of a final report, expected next year.
PM 2.5 standards in the U.S., elsewhere
The update begins with sections explaining PM 2.5, as well as how it’s regulated in the United States and elsewhere.
PM 2.5, measured in micrograms per cubic meter, or µg/m3, are particles so small they’re invisible to the naked eye, but made up of a mix of chemicals that can get deep into the lungs and can cause health problems.
In the United States, PM 2.5 concentrations are regulated by the Clean Air Act, allowing for exposure up to an average of 35 µg/m3 over a 24-hour period, and 9 µg/m3 over an entire year.
The WHO recommended standard is half that — at 30 µg/m3 and 5 µg/m3, respectively.
There are two monitors from the state Department of Environmental Protection in the Valley — in Freemansburg and East Allentown — to ensure compliance.
“In this respect, the fact that the Lehigh Valley air quality measured in two locations meets the standards of air quality required by the Clean Air Act is not sufficient affirmation that air quality is safe for Lehigh Valley residents.”Lehigh Valley Breathes
“A primary purpose of the Lehigh Valley Breathes project is to monitor air quality in areas that are distant from the government’s air monitors, which may not reflect the amount of pollution residents are exposed to in non-proximate locations,” researchers said.
“Our air monitoring network aims to develop an understanding of how pollution levels vary across the Valley and capture the small-scale variations that regulatory monitors often fail to detect.
“In this respect, the fact that the Lehigh Valley air quality measured in two locations meets the standards of air quality required by the Clean Air Act is not sufficient affirmation that air quality is safe for Lehigh Valley residents.”
Comparing sites
For the comparison, researchers used the daily average charts from the last update, which included PM 2.5 concentrations from July 2024 across eight monitoring locations, including urban, rural and residential neighborhoods.
“July is normally a month with relatively high levels of PM2.5 pollution, so it is unlikely that average pollution levels over the month presented in the data snapshot will reflect the level of PM2.5 over the whole year,” researchers said.
“For this reason, we will only relate the data from last month’s newsletter to the daily average standard for PM2.5 pollution. The daily average is based on assessment of 24-hour periods, and the snapshot looked at a full month of 24-hour periods.”
While none of the monitoring sites exceeded the U.S. daily average standard, “we do not want to suggest that this means current air quality sufficiently protects the health of residents in the Lehigh Valley,” officials said.
The first three sites compared were Portland, an isolated rural residential neighborhood; Freemansburg, a suburban area within the urban corridor; and a heavily trafficked road in a dense urban area of Allentown, south of American Parkway, denoted with the acronym PNLV.
“At the PNLV location, the highest daily average in the month of July [2024] was 33.59 μg/m³, which is just below what is allowed by the Clean Air Act in the U.S.,” officials said.
“However, all three sites exceed what the WHO recommends as an allowable daily level of exposure to PM2.5 pollution.”
The second comparison included HellertownBIP, a heavily trafficked urban area situated between an industrial park and Interstate 78; IronRunIP-SG, a suburban area on the northern edge of the Valley’s largest industrial park; and BathIP, a semi-rural area between two industrial parks and just east of a cement plant.
“The highest daily average of PM2.5 pollution at each of the three warehouse sites was above 30 μg/m³ but below the allowable amount of average exposure over a 24-hour period, which is 35 μg/m³,” according to the update.
“However, in these locations, at least half of all days during the month of July (2024) exceeded the WHO recommended daily average standard.”
The third and final comparison looked at two residential monitoring sites in Bethlehem, Kirkland, representing a low-traffic environment, and Brighton, representing a high-traffic environment.
Kirkland was the only location with more than half of the days meeting the WHO recommended level of exposure to PM2.5 pollution, researchers said.
“Among all the sites assessed in this snapshot of July 2024, the lowest average levels of PM2.5 (reflected in the monthly mean concentration represented by a dot on the boxplots) occurred in residential areas removed from either high traffic roadways and/or warehouses."Lehigh Valley Breathes
“Among all the sites assessed in this snapshot of July 2024, the lowest average levels of PM2.5 (reflected in the monthly mean concentration represented by a dot on the boxplots) occurred in residential areas removed from either high traffic roadways and/or warehouses,” officials said.
Requesting feedback
Near the bottom of the latest project update, there’s a section soliciting feedback from residents about the usefulness of regular updates.
“Now that we are beginning to report specific findings from the Lehigh Valley Breathes project, we are curious if these updates are interesting and useful to our readers,” officials said.
“While we realize that these are only updates and not the full, final report, are they meeting your needs for information or are they too detailed and complex?”
So far, researchers haven’t received any responses, Andrea Wittchen of iSpring, a sustainability consulting agency, said.
Residents can email feedback to lvbreathes@gmail.com.
For more information, go to the Lehigh County and Northampton County websites for the project.
