Atmospheric composition change – global and regional air quality

TLDR: A review of the state of scientific understanding in relation to global and regional air quality is outlined in this article, in terms of emissions, processing and transport of trace gases and aerosols.

About: This article is published in Atmospheric Environment.The article was published on 2009-10-01 and is currently open access. It has received 760 citations till now. The article focuses on the topics: Air quality index.

Figures

Fig. 31. (continued).

Fig. 2. A schematic overview of tropospheric chemistry (Courtesy of J. Williams, MPI Mainz).

Fig. 6. Evolution of the global emission of black carbon from three different inventories.

Fig. 32. Monthly averaged contributions to the daily ozone budgets between 09:00 and 17:00 UT for Cape Verde. The data shows the importance of halogen chemistry in this remote marine location in the ozone budget (Read et al., 2008). Reprinted by permission from Macmillan Publishers Ltd: Nature, copyright 2008.

Fig. 17. The difference between measured and calculated OH reactivity versus temperature (circles). The missing OH reactivity, when fitted with the expression E(T) ¼ E(293)exp(b(T – 293)), yields b ¼ 0.11 K 1 with R2 ¼ 0.92 (solid line). This temperature dependence of the missing OH reactivity is almost identical to that of a derived temperature dependence of terpene emissions (Di Carlo et al., 2004) Reprinted with permission from AAAS.

Fig. 28. A typical regional aerosol formation event observed at Hyytiälä, Finland. The continuous growth of newly formed particles is seen with a growth rate of ca 3 nm h 1.

Frequently asked questions

Q1. What are the contributions mentioned in the paper "Atmospheric composition change - global and regional air quality" ?

In this review the state of scientific understanding in relation to global and regional air quality is outlined. Trends in anthropogenic emissions both by region and globally are discussed as well as biomass burning emissions. New findings with respect to the transport of pollutants across the scales are discussed, in particular the move to quantify the impact of long-range transport on regional air quality. In particular, the policy challenges for concerted air quality and climate change policy ( co-benefit ) are discussed. 

Q2. What has led to the emissions of large quantities of pollutants into the atmosphere?

Fossil fuel extraction and burning, energy production and consumption, industrial activities, transportation and landfills have also led to the emissions of large quantities of pollutants into the atmosphere. 

Q3. What is the step forward in deriving parameterizations of topographic venting for larger?

A step forward in deriving parameterizations of topographic venting for larger scale models is the quantification of the air mass exchanged vertically on a sub-grid scale. 

Q4. What are the main areas where understanding is lacking?

Particular areas where understanding is lacking include uncertainties in the mechanisms of the initial oxidation sequences to first generation products, and limitations in the available information on the subsequent chemistry of many of the classes of product known tobe generated. 

Q5. What are the main challenges in the estimation of uncertainties in emissions?

the main challenges in the estimation of uncertainties in emissions are related to the uncertainties in input data and in the development of methods for quantifying systematic errors. 

Q6. How can the amount of anthropogenic dust emissions be evaluated?

By overlaying the distribution of frequency of occurrence with land use changes, the amount of anthropogenic dust emissions can be evaluated. 

Q7. How have the fire emissions estimates evolved over the last three decades?

Over the last three decades, fire emissions estimates have developed from early inventories based on average fire return times and biomass estimates to detailed studies based on satellite data and sophisticated modelling predicting emissions with high spatial and temporal resolution. 

Q8. How has uncertainty in emission scenario analysis been tackled?

Uncertainty in emission scenario analysis at urban scale has also been tackled using Bayesian Monte-Carlo techniques (Deguillaume et al., 2008). 

Q9. What is the important aspect of the degradation of aromatic hydrocarbons?

The degradation of aromatic hydrocarbons, although usually only initiated significantly by reaction with OH, can proceed via a number of different routes to generate a large variety of structurally complex ring-retained and ring-opened products e.g. 

Q10. How can the authors separate pixels with freshly emitted dust from other aerosols?

As dust has some unique spectral signatures (Dubovik et al., 2002), it is possible to separate pixels with freshly emitted dust from other aerosols. 

Q11. What are the technical challenges of HGF measurements in airborne applications?

Technical challenges are also linked to fast hygroscopicity measurements for airborne applications in order to document high altitude hygroscopicity. 

Q12. What are the main questions that remain open?

Other questions also remain open, such as whether the concentrated emissions of gases, aerosols and aerosol precursors in the megacities have a substantial impact on regional and global climate.