Junkyard Fire Put 'Significant' Particulate Matter In Air: Officials

PHILADELPHIA — The junkyard fire that broke out Wednesday afternoon in Philadelphia's Wissinoming section released significant amounts of fine particulate matter, according to health officials.

Philadelphia Health Department monitors reported that the fire released enough matter to classify the air as hazardous to breath.

At 6:42 p.m., the 1-hour PM 2.5 average was 613 ug/m3 (micrograms per cubic meter).

By 8 p.m., PM 2.5 readings had been consistently dropping from that maximum value and continued dropping overnight, officials said.

According to the health department, there is no ongoing threat from PM 2.5 due to the fire, however.

The Health Department had previously reported that no toxic compounds were identified at the site of the fire at levels that would pose a threat to human health.

PM 2.5 are tiny particles in the air that reduce visibility and cause the air to appear hazy when levels are elevated.

PM 2.5, which is sometimes called fine particles or particulate matter, refers to tiny particles or droplets in the air that are two and one half microns or less in width.

The widths of the larger particles in the PM 2.5 size range would be about thirty times smaller than that of a human hair.

PM 2.5 can be dangerous because if you inhale it, the particles are so small they can go deep in your lungs.

PM 2.5 is best measured as an hourly or annual average.

Due to a number of factors, minute readings do not provide a good sense of overall risk, which is why average readings are what warnings are based upon.

Toxic air pollutants, also known as hazardous air pollutants or air toxics, are those pollutants that are known or suspected to cause cancer or other serious health effects, such as reproductive effects or birth defects, or adverse environmental effects.

They are distinguished in air quality monitoring from PM 2.5 and other criteria pollutants, which are air pollutants for which acceptable levels of exposure can be determined and for which an ambient air quality standard has been set.

The PM 2.5 readings at the fire site were exacerbated by smoke from the Canadian wildfires. On the day of the fire, Philadelphia was under a Code Orange Fine Particles Action Day warning.

PM 2.5 readings are currently still high throughout the city, but have not reached the levels that would necessitate a Code Orange Action Day warning.