Diesel particulate levels
Measured in micrograms per cubic meter
This location falls in a census tract with levels of diesel pollution that are likely than percent of all others, with a concentration estimated somewhere micrograms per cubic meter (µg/m³).
Diesel levels nearly anywhere within urban areas or near highway intersections are worse than the benchmark used by Oregon health experts, meaning the vast majority of the country's population breathes diesel particulate matter at levels deemed unsafe. But large swaths of the country — mainly in smaller towns and rural areas — have considerably lower amounts of diesel.
Oregon uses 0.1 µg/m³ as its benchmark to protect human health. Washington uses a smaller number, .003 µg/m³, to calculate the risk from diesel. Over time, exposure to relatively small amounts of diesel can contribute to the risk of cancer, asthma and heart disease. Diesel particulate matter, shown above, is one component of diesel exhaust. It also includes more than 40 known toxic air contaminants like benzene, formaldehyde and heavy metals.
In this location, Environmental Protection Agency models predict cancers from air toxics for every million people who spend a lifetime here. The potential risk solely for diesel particulate matter in this location is estimated to be at least people per million.
For every million people who spent a lifetime in this census tract, these are the numbers of people expected to get cancer from air toxics and from diesel. This is not counting actual cancer instances, but is an estimate from the pollution levels. Keep in mind, this assumes a person has breathed this air every day for 70 years.
Older diesel engines in trucks and buses are the primary source of diesel in cities. Marine vessels also burn diesel, which are a significant source of diesel pollution in areas like Puget Sound and the Portland harbor. Here's a breakdown of diesel sources in different locations:
How do we know this?
The data shown here are derived primarily from the EPA's National Air Toxics Assessment, released in December 2015, which uses known emissions and modeling to determine air toxics risks by census tract throughout the country. To account for assumptions and imperfections in the model, census tracts were grouped into percentiles.
The cancer risk for all air toxics comes from EPA models in the National Air Toxics Assessment, which does not include diesel particulate matter in its risk assessments. Cancer risk for diesel pollution was calculated by using the low end of the particulate matter estimate for the percentile relevant to the census tract for the location entered. That number was then multiplied by a risk factor of 0.0003, a method used by both Washington and California to estimate the cancer risk from diesel particulate. The EPA air toxics cancer risk calculation does factor in some of the same toxics found in diesel, indicating the possibility for some overlap in these two cancer risk figures.
The estimated percentage of diesel by source comes from modeling done by the Oregon DEQ.
Credits
Designed and developed by Tony Schick, OPB/EarthFix. Erik Saganic of Puget Sound Clean Air Association and Kevin Downing of Oregon DEQ provided technical assitance.
Icons: Smoke by Chris from the Noun Project. Truck by Mike Wirth from the Noun Project. Ship by Marc from the Noun Project.