METO 637 Lesson 19

NO x emission inventory

VOC Emissions

Sulfur Dioxide emissions

A Typical Day in a Pollution Episode A common severe pollution weather pattern occurs when high pressure is centered just west of the Mid Atlantic region. Circulation around the high pressure center moves pollution from points west into the mid-Atlantic. H

Fort Meade profile 6/19/2001

After Sunrise Ozone Levels Increase Sharply The ground heats up and the warm air above it erodes the inversion. Ozone and other compounds above the inversion layer mix with the pollution under the layer. This causes a dramatic increase in ground-level ozone, beginning around 10 AM. Temperature Altitude  Sub. inv.  Noct. inv.

Ozone Levels Reach a Maximum in the Afternoon Temperature Altitude  Sub. inv. Temperature Altitude  Sub. inv.  Noct. inv.

After Sunset If the weather remains the same, the temperature inversion forms again after dark. Ozone concentrations above the inversion remain at a constant, relatively, high level. Ozone trapped under the inversion reacts with other pollutants, and the surface; the ozone concentration diminishes. Ozone concentration remaining constant Ozone concentration diminishing Temperature Inversion Temperature Altitude

Westerly transport is often present when the highest ozone is observed in the mid-Atlantic. 24 hr. Back-trajectories on days of 1-hr. ozone exceedances from 1997 through 2002, Baltimore area

Aircraft measurements of ozone

Aircraft measurements of Sulfur Dioxide

Upper level winds from the west… …are turned by the lee side trough Lee Side Trough daytime

Low Level Jet nighttime Air pollution from the southwest… …comes into Maryland overnight

Plot of low-level winds from the Fort Meade, MD wind profiler during a high ozone episode LLJ

9:00 PM11:00 PM 01:00 AM 03:00 AM05:00 AM 07:00 AM Rapid Update Cycle (RUC) model depiction of the LLJ during a high ozone period (high wind speeds in red).

All three modes of transport are important when the highest pollution values are observed in the mid-Atlantic. Large scale ~ 800 km (~ ppbv) (Much of the Eastern US) Medium scale ~ km (Carolinas to New England Region) Small scale ~ 100 km (N. Virginia to Baltimore, Research Triangle to NC/VA border) Modes of Transport

Sources Different types of transport imply different types of sources –Local transport Cars, industry, and other sources in the local area –Long distance transport Primarily power plants to W, though plumes from cities certainly contribute. –Low level jet Primarily cars and other low level sources; moves from SW to NE

Effects of the August 15, 2003 Blackout on Air Quality Compared with Aug 4, 2002 Coming soon to GRL Selinsgrove, PA

Effects of the 2003 Blackout on Air Quality CEM data indicate reductions of 60-80% L. Marufu, B. Taubman, B. Doddridge et al.

Effects of the 2003 Blackout on Air Quality

In summary It isn’t all transport… It isn’t all local… It isn’t all power plants… It isn’t all automobiles… The problem will not be solved by addressing any one of these problems individually. ALL of these will have to show significant reductions for us to breathe clean air.