AERSCREEN is the recommended screening model based on AERMOD. The model will produce estimates of "worst-case" 1-hour concentrations for a single source, without the need for hourly meteorological data, and also includes conversion factors to estimate "worst-case" 3-hour, 8-hour, 24-hour, and annual concentrations. AERSCREEN is intended to produce concentration estimates that are equal to or great...

A steady-state plume model that incorporates air dispersion based on planetary boundary layer turbulence structure and scaling concepts, including treatment of both surface and elevated sources, and both simple and complex terrain....

CALPUFF is an advanced non-steady-state meteorological and air quality modeling system. It is maintained and distributed by Lakes Environmental. The model has been listed by the U.S. Environmental Protection Agency (EPA) as an alternative model for assessing long range transport of pollutants and their impacts on Federal Class I areas and for certain near-field applications involving complex meteo...

This page lists some known alternative models to the preferred/recommended models listed in the Guideline on Air Quality Models, Appendix W that can be used in regulatory applications with case-by-case justification to the Reviewing Authority (Section 3.2 of Appendix W). However, inclusion here does not confer any unique status relative to other alternative models that are being or will be develop...

Measurements of carbon monoxide have been made for over thirty years using a number of different techniques and calibration scales. At the moment the measurements are performed at a number of stations worldwide, however, large regions are still undersampled. This document was created by the WMO/GAW Scientific Advisory Group for Reactive Gases (SAG RG) with the objective to document the various sam...

This document provides detailed guidance on the best practices in use for tropospheric ozone measurements. The focus is on continuous in-situ measurements of ozone in the troposphere, performed in particular at continental or island sites with altitudes ranging from sea level to mountain tops. The purpose of this report is to contribute to a convergence of these practices world-wide in the interes...

SDS-WAS is a research initiative of the World Meteorological Organization that serves as an international framework linking institutions involved in SDS research, operations and delivery of services. SDS-WAS will address the following objectives based on the SDS-WAS Science and Implementation Plan 2020-2025:Facilitate international coordinated research through the Earth system approach to advance ...

On this page, you will find online learning modules on the basics of Atmospheric Composition. These modules are designed to help you, as a forecaster, learn the fundamentals of Atmospheric Composition. The modules will guide you in selecting and using global products from satellites, networks and numerical models throughout the lifecycle of extreme events....

Atmospheric pollution is determined by emissions, chemical transformation, and removal processes, and the latter two are strongly controlled by meteorological processes. Therefore, adequate meteorological forecasting is prerequisite in AQF, and NWP is thus the key and necessary element of any AQF system. For this reason, it is a core task for the World Meteorological Organization (WMO) and NMHSs t...

Migration to cities creates densely populated environments and associated infrastructure. This results in increasing vulnerabilities and exposure to natural and anthropogenic hazards. In 2015, under Transforming our World: the 2030 Agenda for Sustainable Development, the United Nations identified “sustainable cities and communities” as one of its 17 Sustainable Development Goals. This Guidance ser...