Saturday, September 19, 2009

Remote Sensing of Particulate Pollution: Satellite Prospective

Satellite remote sensing of particulate matter air pollution has shown tremendous potential for air quality monitoring over global regions with advancement in research and application over very short period of less than a decade. Recently, Air & Waste Management Association (AWMA) conducted a critical review of research on particle air quality monitoring from satellite observations. Critical review is conducted by experts in the field Ray Hoff from UMBC and Sundar A. Christopher from UAHuntsville.

The Abstract reads as

The recent literature on satellite remote sensing of air quality is reviewed. 2009 is the 50th anniversary of the first satellite atmospheric observations. For the first 40 of those years, atmospheric composition measurements, meteorology, and atmospheric structure and dynamics dominated the missions launched. Since 1995, 42 instruments relevant to air quality measurements have been put into orbit. Trace gases such as ozone, nitric oxide, nitrogen dioxide, water, oxygen/tetraoxygen, bromine oxide, sulfur dioxide, formaldehyde, glyoxal, chlorine dioxide, chlorine monoxide, and nitrate radical have been measured in the stratosphere and troposphere in column measurements. Aerosol optical depth (AOD) is a focus of this review and a significant body of literature exists that shows that ground-level fine particulate matter (PM2.5) can be estimated from columnar AOD. Precision of the measurement of AOD is _20% and the prediction of PM2.5 from AOD is order _30% in the most careful studies. The air quality needs that can use such predictions are examined. Satellite measurements are important to event detection, transport and model prediction, and emission estimation. It is suggested that ground-based measurements, models, and satellite measurements should be viewed as a system, each component of which is necessary to better understand air quality.

Complete Reference

Hoff, R., S.A. Christopher, Remote Sensing of Particualte Matter Air Pollution from Space : Have we reached the promised land, J. Air&Waste Manage. Assoc., 59:642-675, 2009.

Friday, September 11, 2009

Climate Uncertainty and Air Quality

Interesting article on impact of climate uncertainty on regional air quality appeared in ACP earlier this year. Model simulations of the extreme climate scenarios are found to have moderate effect on predicted emissions of VOC and ozone concentration in year 2050.


Uncertainties in calculated impacts of climate forecasts on future regional air quality are investigated using downscaled MM5 meteorological fields from the NASA GISS and MIT IGSM global models and the CMAQ model in 2050 in the continental US. Differences between three future scenarios: high-extreme, low-extreme and base case, are used for quantifying effects of climate uncertainty on regional air quality. GISS, with the IPCC A1B scenario, is used for the base case simulations. IGSM results, in the form of probabilistic distributions, are used to perturb the base case climate to provide the high- and low-extreme scenarios. Impacts of the extreme climate scenarios on concentrations of summertime fourth-highest daily maximum 8-h average ozone are predicted to be up to 10 ppbV (about one-seventh of the current US ozone standard of 75 ppbV) in urban areas of the Northeast, Midwest and Texas due to impacts of meteorological changes, especially temperature and humidity, on the photochemistry of tropospheric ozone formation and increases in biogenic VOC emissions, though the differences in average peak ozone concentrations are about 1–2 ppbV on a regional basis. Differences between the extreme and base scenarios in annualized PM2.5 levels are very location dependent and predicted to range between −1.0 and +1.5μgm−3. Future annualized PM2.5 is less sensitive to the extreme climate scenarios than summertime peak ozone since precipitation scavenging is only slightly affected by the extreme climate scenarios examined. Relative abundances of biogenic VOC and anthropogenic NOx lead to the areas that are most responsive to climate change. Overall, planned controls for decreasing regional ozone and PM2.5 levels will continue be effective in the future under the extreme climate scenarios. However, the impact of climate uncertainties may be substantial in some urban areas and should be included in assessing future regional air quality and emission control requirements.

Complete Reference

Liao, K. J.; Tagaris, E.; Manomaiphiboon, K.; Wang, C.; Woo, J.H.; Amar, P.; He, S.; Russell, A. G. , Quantification of the impact of climate uncertainty on regional air quality, Atmospheric Chemistry and Physics, Volume 9, Issue 3, 2009, pp.865-878