Transcript 投影片 1 - Kun Shan University

Aircraft measurements of O3,
NOx, CO, VOCs, and SO2 in
the Yangtze River Delta region
Student : Shen-Feng Chang
Advisor : Yi-Chyun Hsu
Atmospheric Environment 43 (2009) 584–593
journal homepage: www.elsevier.com/locate/atmosenv
 Introduction
 Description of the measurements
 Analysis of the result
 Introduction (1/3)
The Yangtze River Delta (YRD) region located in
east China (with longitude from 120°E to 121°E,
and latitude from 30.5°N to 31.5°N) is highly
urbanized with a cluster of large cities (including
Shanghai, Hangzhou, Shuzhou, Wuxi, etc.).
Among these large cities, Shanghai has the highest
population in China (about 20 millions).
During the past 20 years, this region is undergoing
a rapid increase in economical development.
 Introduction (2/3)
The GDP has increased by 500% from 1996
to 2006, accounting for more than 5% of the
total GDP in China.
The rapid urbanization causes wide-ranging
potential consequences for weather and climate
related to urban environments, such as air
pollutions.
Like other large cities in east China, Shanghai
is suffering severe air pollution problems, such
as high particular matter (PM) concentrations
and poor visibility.
 Introduction (3/3)
As industrial activities and the number of
automobiles increase together with the changes
in natural activities (such as vegetation and
forest), emission of VOCs and NOx will
significantly increase in the YRD region.
Both VOCs and NOx play critical roles during
O3 formation in the troposphere.
Several studies regarding the air quality in the
YRD region have been conducted.
 Description of the measurements (1/2)
Fig. 1 displays the horizontal routes for several
representative flights.
It shows that the flight routes are located in west
side of the megacity (Shanghai) with several large
cities, such as Suzhou, Wuxi and Jiading.
In addition, there are several large power plants
in this region. For example, the Changshou
power plant generates 1200MW per year.
 Description of the measurements (2/2)
There are totally five flights between
September/30 and October/11 (flight-1 on
September/30, flight-2 on October/2, flight-3
on October/5, flight-4 on October/9, and
flight-5 on October/11), which are analyzed
in this study.
There are also several inter-state high ways,
and high density of small towns and villages.
As a result, the local emissions of air pollutants
from automobiles, and area and point sources
are intensive.
 Analysis of the result (1/2)
Both the O3 mean values are generally lower
than the US national standard values (84 ppbv),
suggesting that the O3 values are modest in the
YRD region.
The NOx concentrations have large variability,
ranging from 3 to 40 ppbv.
The highest concentrations of NOx are observed
normally in the NCITY case, ranging from 10
to 40 ppbv.
 Analysis of the result (2/2)
The SO2 concentrations also have a large
variability, ranging from 1 to 35 ppbv.
The highest concentrations of SO2 are measured
in the NCITY case, ranging from 7 to 35 ppbv.
The CO concentrations are relatively high,
and have smaller variability compared to
NOx and SO2, ranging from 3 to 7 ppmv.
The results are summarized in the follows:
(1) The measured O3 concentrations range from 20
to 60 ppbv.
• These values are normally below the US national
standard (84 ppbv), suggesting that at the present,
the O3 pollutions are modest in this region.
• The NOx concentrations have a large variability,
ranging from 3 to 40 ppbv.
• The SO2 concentrations have very large variability,
ranging from 1 to 35 ppbv.
• The CO concentrations are relatively high, and
have less variability, ranging from 3 to 7 ppmv.
• The concentrations of VOCs are relatively small,
with the total VOC concentration of 6 ppbv.
• Among the total VOCs, alkanes have highest
values (2.8 ppbv).
(2) The relatively small VOC concentrations and
large NOx concentrations indicate that the O3
chemical formation is under “VOC-limited”
regime in the YRD region.
• The measured O3 and NOx concentrations are
strongly anti-correlated, suggesting that
enhancements in NOx concentrations lead to
decrease in O3 concentrations.
(3) The O3 concentrations are more sensitive to
NOx concentrations in the rural PBL region
than in the city region.
• This result suggests that changes in NOx emissions
could have strong effects on O3 concentrations in
rural areas of the YRD region.
(4) The O3-isopleth diagram study shows
that the O3 concentrations could increase
rapidly with increase in VOC concentrations
in the YRD region.
• For example, if the VOC concentrations
increase to 75 ppbC in the future, O3
concentrations could exceed to 84 ppbv,
which is normally considered as the
national standard for human’s health.
Thank you for your attention!