OFFICIAL SITE OF THE STATE OF NEW JERSEYSources of Air Toxics
For the purposes of EPA’s AirToxScreen, formerly known as the National-scale Air Toxics Assessment (NATA), a point source is a stationary facility or process whose location could be identified with latitude and longitude coordinates. Point sources include large facilities that emit a significant amount of air pollution during manufacturing, power generation, heating, incineration, or other such activity. They also include smaller facilities including those that are required to report their emissions under the federal Toxic Release Inventory (TRI) program and the state’s Community Right-To-Know program (CRTK).
These are small stationary sources of air pollution which may not emit very much individually, but their collective emissions account for a significant portion of the total air toxics emissions. They are also referred to as area sources and are generally too small or too numerous to be inventoried individually. The following are some of the source categories grouped under nonpoint sources in EPA’s AirToxScreen:
- Consumer products, including personal care products, household products, adhesives and sealants, automotive products, and coatings such as paints
- Residential heating and fuel use
- Pesticide use
- Gasoline stations
- Dry cleaners
- Institutional and commercial heating
Mobile Sources are divided into two categories:
- On-road mobile sources are vehicles found on roads and highways, including cars, trucks, buses, and motorcycles.
- Non-road mobile sources include aircraft, trains, lawnmowers, boats, dirt bikes, construction vehicles, farm equipment, leaf blowers, and more.
THE NATIONAL AIR TOXICS EMISSIONS INVENTORY
As part of the AirToxScreen process, USEPA prepares a comprehensive list of air toxics emissions for the entire country. This emissions inventory is reviewed and revised by each state before being finalized by USEPA. Although there are bound to be some errors in the details of such a massive undertaking, the inventory gives us a good indication of which are the most important sources of air toxic emissions in our state. As can be seen from the pie chart below, mobile sources combined are the largest contributors of air toxics emissions in New Jersey, with on-road mobile sources accounting for 22%, and non-road mobile sources contributing 32%. Nonpoint/area sources represent 41% of the inventory. The remaining 5% of the inventory is attributable to point sources.
Note that this pie chart does not include emissions of diesel particulate matter. For a discussion of diesel emissions, click here. The 1990 – 2014 NATA and the 2017 AirToxScreen results were discussed on this website previously, and can still be accessed by clicking 1990, 1996, 1999, 2002, 2005, 2011, 2014, 2017. However, USEPA emphasizes that the methods used to compile emissions inventories vary somewhat from year to year, so the results are not exactly comparable.
COMPARISON OF EMISSIONS BY COUNTY
When the New Jersey emissions estimates are broken down by county, it is evident that the areas with the greatest air toxic emissions are generally those with the largest population. This is directly related to high levels of vehicle use, residential fuel burning, solvent use, and other population-related activities in those counties.
POLLUTANTS WITH SIGNIFICANT CONCENTRATIONS FROM BACKGROUND & TRANSFORMATION
Concentrations of some air toxics are dominated not by local emissions, but by atmospheric transformation (or secondary formation) and by what USEPA refers to as background estimates.
Secondary formation, or atmospheric transformation, occurs when chemicals are transformed into other chemicals in the atmosphere. When a chemical is transformed, the original pollutant no longer exists and is replaced by one or more new chemicals. A chemical that transformed from other pollutants can be more, less, or equally toxic to its precursors. Transformations and removal processes affect both the fate of a pollutant and its atmospheric persistence. EPA’s AirToxScreen uses secondary formation and atmospheric transformation interchangeably.
Formaldehyde is New Jersey’s primary air toxic of concern from secondary formation.
Background concentrations are existing levels of pollutants from natural sources, non-industrial human activities, and out of state industrial facilities. EPA describes background ambient air concentrations as values averaged over broad geographic regions. Background concentrations can account for pollutant concentrations found even without recent human-caused emissions.
Carbon tetrachloride is consistently considered an air toxic of concern in New Jersey, with estimated statewide average background concentrations exceeding the health benchmark.