Lakes Environmental Newsletter
Lakes Software Monthly Newsletter


Monthly Newsletter - July 2021

AERSCREEN View Version 3.0 Released

AERMOD header

Earlier this week, we released AERSCREEN View Version 3.0. This release includes the following updates:

  • New Models: Latest US EPA AERSCREEN and MAKEMET models (Version 21112)
  • Updated AERMOD: Utilizes the latest US EPA AERMOD model version 21112 with 32-bit & 64-bit compatibility
  • New WebGIS Terrain: Automated download of USGS National Elevation Dataset (NED) GEOTIFF tiles over North America*

* NED downloads via WebGIS are only available to users with current paid maintenance.

Check out our latest release notes for a detailed listing of AERSCREEN View updates.

If you are currently in maintenance for AERSCREEN View and did not receive an email regarding this update, please contact us at

If you are a user of AERSCREEN View but are no longer in maintenance, please contact our sales team at for pricing to update your license.

AERMOD View Version 10.0.1 Released

AERMOD header

Earlier this month, we released AERMOD View Version 10.0.1. The release includes the following updates:

A full list of improvements made by the U.S. EPA for each model can be found on the AERMOD and AERMET web pages. Significant updates provided in AERMOD View Version 10.0.1 include:

  • Building Downwash: An update was made to ensure the application opens older projects with the proper downwash setting
  • Import Sources: The Lakes Format spreadsheet template can be used to replace existing source parameters
  • Models: In Preferences, release dates have been added to the default executables

Check out our latest release notes for a detailed listing of AERMOD View updates.

If you are currently in maintenance for AERMOD View and did not receive an email regarding this update, please contact us at

If you are a user of AERMOD View but are no longer in maintenance, please contact our sales team at for pricing to update your software to ensure that your regulatory agency or industrial clients are using the official EPA AERMOD Version.

Online AERMOD Course – Sep 21-22, 2021 - Only One Spot Left!

Online Training header

Space is almost gone for our 2-day online AERMOD course taking place on September 21 and 22, 2021. from 8:30am to 5:00pm (Central Time).

Don't miss out! Register today!

Note: Due to the immense popularity of our online courses and small class sizes, we recommend registering and making payment as soon as possible.


AERMOD (Sep 21-22, 2021)



Online CALPUFF Course – Sep 28-29, 2021

Online Training header

Our team will present 2 days of online CALPUFF training from September 28 and 29, 2021. The same great course, now from the convenience of your home or office!

Space is limited. Register today!


CALPUFF (Sep 28-29, 2021)



Just Announced – New Online AERMOD Courses!

Online Training header

We’re pleased to announce the following upcoming Online AERMOD Air Dispersion Modeling Courses. Join us for world class training from the safety of your own home or office with our senior level air quality experts!

Register and pay today before space is gone!

AERMOD: Oct 26-27, 2021

AERMOD: Dec 7-8, 2021

AERMOD: Jan 18-19, 2022

Online registration is available now. Our online courses sell out quickly! We recommend registering and making payment as soon as possible.

Lakes Environmental Closed for Ontario Civic Holiday

Lakes Environmental’s offices will be closed on Monday, August 2, 2021 to observe the Ontario Civic holiday. If you have any support needs during that time, please e-mail us at and we will contact you on Tuesday, August 3, 2021 when our offices reopen.


2021 Course Schedule

Sep 21-22, 2021
Register →

Sep 28-29, 2021
Register →

Oct 26-27, 2021
Register →

Dec 7-8, 2021
Register →

Jan 18-19, 2022
Register →

aqmis ad


PVMRM Bug in AERMOD 21112

The Plume Volume Molar Ratio Method (PVMRM) is one of several methods built into AERMOD for assessing the conversion of NOX to NO2. Originally developed by Hanrahan as a post-processor for the ISCST3 model, this conversion method is considered a Tier 3 screening method according to the Guideline on Air Quality Models (Appendix W to 40 CFR Part 51). The conversion rate for NOX to NO2 in this scheme is based on a calculation of NOX moles emitted into the plume and the amount of ozone (O3) moles contained within the volume of the plume between the source and receptor.

When modeling PVMRM, users must supply in-stack NO2 / NOX ratios – which can be customized for each source – and background ozone concentrations. Background ozone values can vary from a single value representing the entire domain for the duration of the run to hourly values – like those taken from a monitor – which can vary by downwind sector.

In AERMOD View, background ozone values are input via the Control Pathway. To enable this feature, users must have the following options enabled:

Modeling Tip picture

In Pollutant/Averaging, the pollutant Type to NO2

Modeling Tip picture

In NOx to NO2 Options, select PVMRM from the Tier 3 options

In addition to background ozone, users can also input background NO2 concentrations. These serve as additive values as additive values to the model-calculated concentrations and are input via the Source Pathway as shown below.

Modeling Tip picture

As with background ozone, these values can vary temporally – either hourly or by pre-defined repeating scales – and spatially by downwind sector.

The 21112 version of AERMOD published by the U.S. EPA on May 11, 2021 and incorporated in AERMOD View Version 10.0.1 contains a bug when reading background NO2 values from the Source Pathway. The bug causes background NO2 to be incorporated into the model calculations twice effectively doubling the amount of this background NO2 data.

The workaround is to input half of the actual background NO2 values. This way, the doubled background will work as the actual value.

The EPA plans to fix this issue in a future release of the AERMOD model.

As an example of the workaround, if your actual background NO2 was a single annual value of 30 µg/m3 you would input 15 µg/m3 using the “By Year (ANNUAL)” selection.

Modeling Tip picture

If you input hourly values using an Hourly Background Concentration File, each value must be halved. Note that you can build an hourly background data file using the Concentration File Maker utility.

Modeling Tip picture

The U.S. EPA has not released a timeline for fixing this issue, so modelers should take note of which projects they run containing reduced background ozone values. Whenever an updated AERMOD is available, Lakes will incorporate that into AERMOD View and advise on any further steps users need to take at that time.



June 2021 Was the Hottest June on Record for U.S.

July 9, 2021 - Exceptional heat waves from coast to coast helped push June 2021 to the No. 1 spot on the list of hottest Junes on record for the U.S.

Read more →

New Satellite Data Techniques Reveal Coastal Sea-Level Rise

July 7, 2021- For the hundreds of millions of people living in coastal regions around the world, rising seas driven by climate change pose a direct threat. In order for authorities to plan appropriate protection strategies, accurate information on sea-level rise close to the coast is imperative. For various reasons, these measurements are difficult to get from satellites. However, new ESA-funded research demonstrates how a specific way of processing satellite altimetry data now makes it possible to determine sea-level change in coastal areas with millimetre per year accuracy, and even if the sea is covered by ice.

Read more →

Additional Environmental News

Visit the Environmental News Network (ENN), the most dependable online environmental news source!



Lakes Footer
Tauria Footer
ENN Footer

Lakes Logo
twitter   facebook   linkedin

1-170 Columbia St. W.
Waterloo, ON N2L 3L3

View Online

This newsletter contains information gleaned from various sources on the web, with complete links
to the sources cited. Organizations cited are in no way affiliated with Lakes Environmental Software.

For more information, please visit our web site at:
All comments and suggestions are welcome.  You can e-mail us at:
Privacy Policy