in SO 2 emissions were achieved in North America
and Europe, resulting in some regeneration and
recovery of many forests and water bodies in these
areas. The current guideline set by the World
Health Organization (WHO) for SO 2 is
20 mg m
À3 (24-h average). A study looking at
annual average SO 2 concentrations for the late
1990s of various megacities (cities with
populations greater than ten million) worldwide
found that a number of cities, such as Dhaka,
Bangladesh, Beijing, China, and Shanghai,
China were still above this guideline; most other
cited megacities in the study had annual average
concentrations of just under 25 mg m
À3 [12]. Additionally, SO 2 emissions from megacities in Asia
accounted for 30% of the ambient concentrations
measured regionally, including areas hundreds of
kilometers from the urban centers [13]. Levels of
SO 2 measured in the USA declined by 59% from
1990 to 2008, and are currently well below the
0.03 ppmV (~80 mg m
À3 ) national standard. The
majority of the monitoring sites in the USA report
SO 2 annual average levels between approximately
0.002 and 0.008 ppmV for 2008 [10].
Similar to SO 2 , power plants are a significant
emissions source for nitrogen oxides (NO x ). However, NO x has many other important emission
sources including mobile sources, which make up
the majority of global NO x emissions, as well as
biomass burning, and natural emissions from soils
and lightning [2, 5]. NO x is the collective term for
NO and NO 2 as the photolysis of NO 2 to NO and the
subsequent regeneration of NO 2 via reaction of NO
with ozone is sufficiently fast, in the moderately
polluted environment, for these species to be in
dynamic equilibrium, namely,
0 – 0.3
UK Emissions Map of
Carbon Monoxide (as C) 2005 t/1×1km
0.3 – 0.5
© Crown copyright. All rights reserved defra Licence number 100018880 2007.
0.5–2
2–3
3 –16
16 –160
160 –143,550
Regional Air Quality,
Fig. 3 Spatially
disaggregated emissions of
carbon monoxide in the UK
from 2008 (Murrells et al. [8])
352
Regional Air Quality
and Europe, resulting in some regeneration and
recovery of many forests and water bodies in these
areas. The current guideline set by the World
Health Organization (WHO) for SO 2 is
20 mg m
À3 (24-h average). A study looking at
annual average SO 2 concentrations for the late
1990s of various megacities (cities with
populations greater than ten million) worldwide
found that a number of cities, such as Dhaka,
Bangladesh, Beijing, China, and Shanghai,
China were still above this guideline; most other
cited megacities in the study had annual average
concentrations of just under 25 mg m
À3 [12]. Additionally, SO 2 emissions from megacities in Asia
accounted for 30% of the ambient concentrations
measured regionally, including areas hundreds of
kilometers from the urban centers [13]. Levels of
SO 2 measured in the USA declined by 59% from
1990 to 2008, and are currently well below the
0.03 ppmV (~80 mg m
À3 ) national standard. The
majority of the monitoring sites in the USA report
SO 2 annual average levels between approximately
0.002 and 0.008 ppmV for 2008 [10].
Similar to SO 2 , power plants are a significant
emissions source for nitrogen oxides (NO x ). However, NO x has many other important emission
sources including mobile sources, which make up
the majority of global NO x emissions, as well as
biomass burning, and natural emissions from soils
and lightning [2, 5]. NO x is the collective term for
NO and NO 2 as the photolysis of NO 2 to NO and the
subsequent regeneration of NO 2 via reaction of NO
with ozone is sufficiently fast, in the moderately
polluted environment, for these species to be in
dynamic equilibrium, namely,
0 – 0.3
UK Emissions Map of
Carbon Monoxide (as C) 2005 t/1×1km
0.3 – 0.5
© Crown copyright. All rights reserved defra Licence number 100018880 2007.
0.5–2
2–3
3 –16
16 –160
160 –143,550
Regional Air Quality,
Fig. 3 Spatially
disaggregated emissions of
carbon monoxide in the UK
from 2008 (Murrells et al. [8])
352
Regional Air Quality