Why POC in NEI2017 is the highest relative to previous NEI dataset?

Hello,

I compared the NEI2017 POC from nonpt sources with data from NEI 2011, 2014, and 2016, as well as the annual POC from the 2002-2017 EQUATES inventory. I did not find a clear reason to explain the highest POC levels in 2017.

Could you guide me on where I might find information on the uncertainty for the nonpt POC in 2017? Additionally, is there any paper evaluating the emissions or model performance for predicting OC or PM2.5 concentrations using NEI2017?

Thanks in advance.

We suspect the main issues are fires and updated speciation. You can review the EIS sector summaries available on the trends site to at least narrow down the question. From there, you can dig into the state/SCC dataset provided for trends to get the specific SCC(s) if that level of detail is needed.

See https://www.epa.gov/air-emissions-inventories/air-pollutant-emissions-trends-data for more information. Our recent data for trends includes EC and OC.

Hi Alison,

I see, Thank you for your reply and this information!
I found the double POC emissions from nonpt in NEI2017 in Baltimore city. It may be not related with fire emission.

Can you provide some more information about what you found in Baltimore? Is it in 2017 and not other years?

Yes, I compared the county monthly emission data from epa website. It is doubled in 2017 relative to 2016 in Baltimore for nonpt POC.