This study was conducted to identify and quantify the sources of selected volatile organic compounds (VOCs) and fine particulate matter (PM2.5) by using a partially constrained source apportionment model suitable for multiple time resolution data. Hourly VOC, 12-h and 24-h PM2.5 speciation data were collected during three seasons in 2013. Eight factors were retrieved from the Positive Matrix Facto...

This technical support document (TSD) describes the air quality modeling performed to support the final Cross State Air Pollution Rule for the 2008 ozone National Ambient Air Quality Standards (NAAQS). In this document, air quality modeling is used to project ozone concentrations at individual monitoring sites to 2017 and to estimate state-by-state contributions to those 2017 concentrations. The p...

Efforts have been made to relate measured concentrations of airborne constituents to their origins for more than 50 years. During this time interval, there have been developments in the measurement technology to gather highly time-resolved, detailed chemical compositional data. Similarly, the improvements in computers have permitted a parallel development of data analysis tools that permit the ext...

Atmospheric models serve an essential role in guiding air pollution management by  assessing health impacts from various sources. In the US and other developed nations,  chemical transport models (CTMs) are used to predict pollutant concentrations and to  evaluate compliance with air quality standards. CTMs are state-of-the-science models  but are resource-intensive requiring s...

Each year, millions of premature deaths worldwide are caused by exposure to outdoor air pollution, especially fine particulate matter (PM2.5). Designing policies to reduce these deaths relies on air quality modeling for estimating changes in PM2.5 concentrations from many scenarios at high spatial resolution. However, air quality modeling typically has substantial requirements for computation and ...

Every day, CAMS provides five-day global forecasts for:Aeorosol Optical DepthCarbon DioxideCarbon MonoxideFormaldehyde MethaneNitrogen DioxideOzoneParticulate MatterSulphur DioxideUV IndexFire Activity ...

The Modern-Era Retrospective analysis for Research and Applications, Version 2 (MERRA-2) provides data beginning in 1980. It was introduced to replace the original MERRA dataset because of the advances made in the assimilation system that enable assimilation of modern hyperspectral radiance and microwave observations, along with GPS-Radio Occultation datasets. It also uses NASA's ozone profile obs...

The GEOS Composition Forecasting (GEOS-CF) system produces global, three-dimensional distributions of atmospheric composition. The spatial resolution is 25km. Using meteorological analyses from other GEOS systems, the GEOS-CF products include a running atmospheric replay to provide near-time estimates of surface pollutant distributions and the composition of the troposphere and stratosphere. A sin...

This study presents the source apportionment of PM2.5 performed by positive matrix factorization (PMF) on data presented here which were collected at urban (Institute of Atmospheric Physics – IAP) and rural (Pinggu – PG) sites in Beijing as part of the Atmospheric Pollution and Human Health in a Chinese megacity (APHH-Beijing) field campaigns. The campaigns were carried out from 9 November to 11 D...

This annex to the European Monitoring and Evaluation Programme (EMEP)'s General Guidance on the Spatial Mapping of Emissions provides a general tiered guidance for the spatial disaggregation of emissions by sector....