The MODIS AOD image, below left, shows low values of AOD across the country for today. There does appear to be scattered increases in AOD in the Southeast and a band of increased AOD along the western coastline of the U.S. West Texas also has an increase in AOD. The KNMI OMI NRT NO2 product below right, shows increases in NO2 throughout the troposphere. There appears to be an increase in the Gulf Region and Mexico. For this reason, there may be some increased nitrate aerosol and particulate formation that will affect air quality at the surface.

Below, left. the GEOS Chem model shows in increase in total AOD for the northeast and New England regions of the U.S. The heaviest concentrations appear to be north eastward of the concentrated fire region in the southeast region. Below, right courtesy NOAA HMS, shows the fire locations for the day. There are concentrated fires in the Plains and Southeast region that correspond well to the increase in AOD from above. There does appear to be small smoke plumes being advected near the Gulf region.

Winter storm Juno has made its way up the East Coast, with the most snowfall being recorded in New England. Some cities in the region saw as much as 3 feet of snow fall (apparently making Juno the sixth biggest recorded snow storm to ever hit Boston). A satellite view of the storm approaching New England can be seen in the NOAA image below.

With that in mind, AQIs are low throughout most of the nation (EPA AirNow, left). Air quality in the Southeast is seemingly unfazed by the small, isolated fires dotting the region--producing small puffs of light smoke (NOAA HMS, right). AQIs in the West, however, are mostly Moderate with a few episodes of USG for a couple hours during the day in Northern California. Possibly related, the NAAPS Aerosol model predicts a thin strip of dust over central California with a surface concentration between 20-40 ug/m^3.

Saturday saw Santa Ana winds in Southern California with major wind storm damage and some limited wildfire activity. By Sunday, however, the Santa Ana has disorganized and there are variable wind directions in Southern California. In the San Joaquin Valley, fog covers the entire region. AQI levels overnight Sunday showed some elevated levels in Northern California, Oregon and Idaho. AQI decreased in the East as winds are picking up with a major storm brewing through the lower great lakes.

This storm can be seen in the METAR wind barbs east of the Mississippi River and the cloud shield. This storm will move east over the next 48 hours and intensify greatly when it reaches the ocean. 2-3 feet of snow is forecast for the northeast states.

Smoke, presumably from numerous agricultural fires was captured in today's Aqua MODIS rgb retrieval over the Southeastern US. In addition, light winds limited pollutant dispersion, with particulate levels increasing near the surface. Size distribution retrievals from sun photometer measurements at Georgia Tech show the presence of coarse particulate in the atmosphere. Airnow animation for this region show that PM2.5 concentrations ranged in the Code Yellow AQI. Code Red AQI PM2.5 levels were reported in California, with NO2 tropospheric column retrievals being the greatest over this region.

Overall US air quality is Moderate today except for cases of elevated AQIs in Northern Idaho and Southern California (EPA AirNow PM Loop, below). The Salmon, Idaho area reached an Unhealthy AQI of 174 with stagnant winds (maximum of 2 m/s, http://aqicn.org/city/usa/idaho/salmon/) holding PM pollution, despite the colder weather there. The warm, urban weather in the Los Angeles area, however, houses fewer Unhealthy AQIs but plenty of areas USG.

A growing swath of Moderate AQIs plagues the East US. HMS Fire Imagery (left) shows groups of small, isolated agricultural burnings over most of the Southeast. Some of these fires are producing light smoke; the NAAPS aerosol model (right) predicts the smoke surface concentration to reach 16 ug/m^3 over a few states in the Mississippi valley region, where the burnings are most concentrated.

The air quality situation today is not bad for winter, with moderate AQI in the San Joaquin Valley. There is heavy fog in the valley so the lack of sunlight probably is helping to keep the particulate pollution down. In the Mississippi Valley and eastward there are broad regions which are in the Moderate AQI PM levels. Some good news is that we are now generating UMBC MPL lidar results again. Over the winter break the system went down and was not restored (mea culpa). At least now we are generating lidar cross sections again from UMBC.

Other parts of the globe are seeing significant aerosol events. Off Africa dust and smoke are pouring out of the Sahel region of Africa. And in India the whole subcontinent is covered in haze.

There are more areas of poor air quality in the US on Sunday, including some code red readings in the San Joaquin Valley, Northern California Sierras and in Idaho. The San Joaquin Valley is still fog covered so stagnant air is evident, and pollutants are building up.

These wintertime cases of high PM often are related to wood burning coupled with low inversion heights and stagnation. The control options are very limited in these situations and this has brought about a policy battle in Utah where the Governor has put forward a proposal for restrictions on wood burning . Understandably, people who have always burnt wood for cultural and historical reasons are irritated, but there is also a question of environmental justice involved in this debate.

In California in 2013, we were told about the local residents who were quite poor and how they had to burn anything (garbage, transportation skids, wood residue, etc.) to stay warm in the winter. One can argue that you don't have the "right" to put people's health at risk by polluting the air and more than you would poison a well. But one also has to respect the right to "welfare of the public" and freezing to death in the winter is not a preferable option. This debate should include the necessity of providing alternate fuel or financial support to poor people who would die without wood heating. We watch this policy debate with interest.