Air Quality Essay, Research Paper

Today, the air quality aspect of ARL research is by far the dominant theme, but

distinctions among the themes remain somewhat vague. For example, the models

developed for emergency response purposes are among those used for air quality

prediction. The Air Quality and Dispersion theme is one of the strongest ties

that binds ARL’s components together. ARL is not heavily involved in the pure

science of the business. Instead, ARL focusses on the need to assemble

integrated understanding and models from all available sources, to develop the

capability to predict changes in air quality that will follow changes in

emissions, or that will occur as a result of meteorological factors. ARL air

quality research extends to studies of atmospheric deposition essentially the

coupling between the atmospheric pollutant environment and the surface below.

ARL now operates the only research-grade deposition monitoring network in the

nation: AIRMoN (the Atmospheric Integrated Research Monitoring Network).

Programs. Air Quality and Deposition Modeling Air quality models have demanded

this kind of coupling for a considerable time. As a result, there are now

well-developed descriptions of PBL processes in use in air quality models. ARL

research products are now receiving a wider audience, within the mesoscale

modeling community at large. It is recognized that modern models are invariably

data assimilative, and that modern monitoring programs require coupled modeling

activities for data interpretation. Model development programs are supported by

a vigorous physical modeling program, located at Research Triangle Park, NC. ARL

operates one of the nation’s major fluid modeling facilities, at which studies

are conducted on the effects of mountains, buildings, and other surface

obstacles on atmospheric flow patterns. Integrated Monitoring, and AIRMoN The

Atmospheric Integrated Research Monitoring Network is an atmospheric component

to the overall national integrated monitoring initiative that is currently

evolving. AIRMoN has two principal components: wet and dry deposition. ARL

presently focuses its research attention on  the measurement of

precipitation chemistry with fine time resolution (AIRMoN-wet),  the

development of systems for measuring deposition, both wet and dry,  the

measurement of dry deposition using micrometeorological methods (AIRMoN-dry),

 the development of techniques for assessing air-surface exchange in

areas (such as specific watersheds) where intensive studies are not feasible,

and  the extension of local measurements and knowledge to describe areal

average exchange in numerical models. Aerosols and visibility ARL specializes in

the geochemical cycling of atmospheric aerosols, particularly the particulate

component. Research groups in ARL concentrate on (a) the injection of dust and

soil particles into the atmosphere, (b) the transport of particles through the

atmosphere, ? the production of aerosol particles in the air by chemical

reactions, (d) the scavenging of airborne particles by clouds and their

subsequent deposition in precipitation, (e) the dry deposition of particles as

air moves across different landscapes, and (f) the assembly of numerical models.

Specific topics include  the injection of dust and soil particles into

the atmosphere,  the long-range transport of particles through the

atmosphere,  the production of aerosol particles in the air by chemical

reactions,  the scavenging of airborne particles by clouds and their

subsequent deposition in precipitation, and  the dry deposition of

particles as air moves across different landscapes. International ARL serves as

the leader of the U.S. multi-agency effort to impose formalized and uniform

quality assurance programs on the many national air quality and deposition

monitoring networks that are operational around the globe. How are ozone

concentrations calculated with Hysplit? Ozone is then calculated from the

photostationary state equation. The IER solution is used in the operational

Hysplit ozone calculation. The pollutant particles are tracked and air

concentrations for each species are computed each advection time step following

the usual lagrangian approaches. At the conclusion of the advection step the GRS

differential equations are solved on the concentration grid (Eulerian solution),

and the change of concentration of each pollutant species is applied to the

pollutant mass on the particles that contributed concentration to each grid

cell. -Eulerian chemistry solution on the grid dc/dt = {Equations 1 – 7} 1) ROC

+ hv -* RP + ROC Nitric oxide-ozone titration reaction 5) RP + RP -* RP k5 =

10200 Sink for nitrogen dioxide to stable gaseous nitrates What is the

Integrated Empirical Rate Model? Time Integrated on the particle (Lagrangian):

Algebraic solution on the grid (Eulerian): Smog product = ozone produced and

oxidized nitric oxide Photostationary state balances formation and destruction

of ozone Definition of NOx Air-Surface Exchange Heat, Momentum, Water, and CO2

Transfer at the Earth Surface Presently, ARL focuses its attention on the

development of systems for measuring fluxes at specific locations, and the

extension of local measurements and understanding to describe areal average

exchange in numerical models. Improving NOAA’s prediction capabilities requires

this understanding. ARL’s internal model developments are arranged to be in

close association with the field work. Tower Studies. Dennis Baldocchi ([email protected])

Three ARL groups (Oak Ridge, Research Triangle Park, and Silver Spring) are

currently working with portable eddy flux systems, based upon original ARL

developments. The system is specifically designed to provide uninterrupted

monitoring of momentum, heat, water vapor, and carbon dioxide fluxes. Walker

Branch watershed flux studies have recently been extended in an exploration of

the flux contributions of the forest floor and the trees themselves. Experience

gained in this effort will be important for anticipated surface-layer model

testing and evaluation studies (under NOAA/GEWEX/GCIP). At Research Triangle

Park, and in cooperation with Oak Ridge, a separate portable flux-measuring

system was developed, this time designed for direct measurement of trace gas

fluxes but relying on measurement of the standard micrometeorological quantities

for quality assurance. The system provides for direct eddy correlation

measurements of sulfur dioxide, ozone, and carbon dioxide fluxes, and of nitric

acid by filter pack gradient analysis, as well as the important components of

the surface energy budget. The Mobile Flux Platform, and GPS. Ron Dobosy ([email protected])

During 1994, the use of new Global Positioning System (GPS) technology was

evaluated, and the newest available GPS systems were adopted. The systems

developed for aircraft eddy flux use have now been fitted to one of NOAA’s two

Twin Otter aircraft. Large-Area Exchange Tim Crawford ([email protected])

The Oak Ridge group has frequently deployed both tower and aircraft eddy

correlation systems during studies of areal fluxes over a heterogenous surfaces,

in real-world studies of how well flat-earth formulations apply in real

situations. Analysis of tower eddy correlation fluxes of heat and moisture

displayed differences in the fluxes among alfalfa, corn, and wheat crops; during

daytime, transpiration rates differed by 20% to 50%. Measurements of momentum,

heat, and moisture fluxes from the ATDD Long-EZ research airplane were analyzed

to quantify spatial variabilities in the fluxes. Carbon Dioxide. Tilden Meyers ([email protected])

Continuous eddy correlation measurement of CO2 flux over the Walker Branch (Oak

Ridge) forest have continued since 1993. The eddy flux measurement of CO2

exchange is now a mature technology. (See discussion above — "Tower

Studies".) Air-surface exchange has been studied extensively in classical

investigations that focus on revealing the processes involved. Winston Luke ([email protected])

The importance of accurate air-surface flux formulation in numerical models is

now widely acknowledged. Atmospheric Loadings to Coastal Ecosystems Regulatory

strategies that fail to recognize that part of the problem arises from

atmospheric deposition will not work as expected. The ARL Role Measurement and

modeling of atmospheric deposition are long-standing ARL specialties. east

coast, from Maine to Florida. ARL is leading a large part of the integrated

research effort focusing on this issue. Leadership of the Chesapeake Bay Air

Subcommittee Contact — [email protected] The Chesapeake Bay Program (CBP)

is a multi-agency program of targeted scientific research and integrated

assessment, which has been instrumental in alerting policy makers to the need to

couple air and water issues in their decision-making processes. Characterizing

the East and Gulf Coast Atmospheric Resource Contact — [email protected] It

is clear that emissions from the "airshed" that serves as a regional

origin of air pollutants affecting the Chesapeake Bay also influence other

coastal ecosystems. east coast estuarine and coastal ecosystems would benefit as

well. Research Grade Monitoring of Deposition in the Coastal Zone Contact –

[email protected] The atmospheric deposition that affects east coast

ecosystems is very poorly measured. For dry deposition, there are very few data

points. The NOAA Atmospheric Integrated Research Monitoring Network (AIRMoN) has

constituted a framework for exploring methods for quantifying the actual

deposition loadings to the Chesapeake Bay watershed. ARL is currently operating

several AIRMoN stations in the watershed — State College, PA, is a long-term

site where both wet and dry deposition are being studied. Modeling Deposition to

the Coastal Zone at Regional Scales Contact — [email protected] The Regional

Acid Deposition Model (RADM) has been adopted as the modeling workhorse of the

east coast estuarine regulatory community. The results indicate that grid sizes

*2 km may be necessary to resolve the effects of the Bay on atmospheric dry

deposition (but not wet). Estimating Air-Water Exchange of Nitric Acid in

Coastal Areas Contact — [email protected] A project was successfully

undertaken which, i) developed and evaluated an iterative bulk exchange model to

estimate air-water exchange of heat, water and momentum from buoy data, and ii)

used the model outputs to estimate air-water transfer rates of nitric acid

(HNO3). Natural emissions of Oxidant precursors: Validation of techniques and

Assessment (NOVA) Contact — [email protected] Historically, NOx emissions

from soils have been estimated using chamber, or enclosure, techniques, whereby

the measured rate of increase of [NO] within the chamber used to derive an

estimate of the NO emission flux from the underlying soil surface. Mercury

Deposition Contact — [email protected] ARL researchers at Oak Ridge (a

collaboration between ATDD and Oak Ridge National Laboratory) have been working

on techniques to measure the deposition of mercury directly. More recently,

field studies have been conducted in southern Florida, where mercury originating

from sugar farming practices is suspected to be affecting coastal ecosystem

viability. Research Plans Linkages within NOAA The ARL coastal studies program

is strongly linked with the NOAA Chesapeake Bay Office of the National Marine

Fisheries Service. The work is also tied to the NOAA Coastal Ocean Program, and

to coastal activities of the National Ocean Service. The Chesapeake Bay Air

Subcommittee (led by ARL) serves as an interface with all federal agencies

involved in related research (EPA, DOD, DOE, DOI, DOA, NASA, Smithsonian) as

well as with the air and water environmental components of each of the states in

the Chesapeake Bay region (Delaware, New York, Pennsylvania, Maryland, Virginia,

District of Columbia, West Virginia). The NPS Air Resources Division synthesizes

information acquired through the NPS air quality research and monitoring

programs, disseminates the information to park personnel and managers, and works

with park personnel to develop air quality related interpretive goals, themes,

projects and activities. NPS interpretive programs serve to educate the park

visitor about air resource by: Describing statutory authorities which help the

NPS protect air resources. In 1983, barely a half dozen parks were using air

quality information in interpretive/educational programs.