Environmental Engineering Reference
In-Depth Information
0,14
day
0,12
night
0,10
0,08
0,06
0,04
0,02
0,00
seasons 2005 to 2007
Fig. 1
Average PM
2.5
mass concentrations in different seasons from 2005 till 2007
0,200
MovAv_Day
0,175
MovAv_Night
0,150
0,125
0,100
0,075
0,050
0,025
0,000
calender weeks between 2005 and 2007
Fig. 2
Average mass concentrations of PM2.5 sampled during daytime and nighttime between
2005 and 2007
In winter time, emissions from combustion processes for heating and industry
accumulate and produce high concentrations of PM
2.5
, especially in cases of low
wind speed and southern and eastern wind directions
[16]
. Figure
2
presents the
mean PM
2.5
concentrations of all five stations calculated as moving average.
This was calculated according to the formula: ac
wn
= (c
wm
+ 2c
wn
+ c
wo
)/4; ac
wn
:
moving average of mean aerosol concentration of all five sites of week n, c
wm
: mean
aerosol concentration of all five sites of week
m
, which is the week before week
n
,
