Air State and Impact
Ambient air
pollution
- Dust
pollution
- Pollution due to SO2
- Pollution due to CO, NO2
and O3
- Lead
(Pb) pollution in
urban
air
Impact of air
pollution
Dust
pollution
Results
from environmental monitoring stations and the State of Environment
Reports of provinces and cities from 1995 to 1999, show that most urban
areas in Vietnam are polluted by dust, and some centers are polluted to an
alarming degree. According to Vietnam Environment Standards (TCVN) 5937-
1995, permitted standard of daily average suspended dust concentration is
0.2 mg/m3 and permitted standard of hourly average suspended
dust concentration is 0.3 mg/m3.
In residential areas that are far away from traffic roads or from production facilities, and within green parks, dust contents approximate the permitted standards.
|
In
residential areas next to factories or near large traffic roads,
dust concentration is often higher 1.3 to threefold the acceptable
level. The residential areas near brick and beer plants in Lao Cai
town have dust concentration that is fivefold higher than the
permitted standard. The places with highest levels of air pollution
are residential areas near Hai Phong cement plant, VICASA plant (Bien Hoa), Tan Binh
industrial zone (Ho Chi Minh City), and Hon Gai coal select plant
(Ha Long City). |
Dust content in ordinary residential quarters of cities
and towns are 1.2 to 2 fold higher than the permitted standard. In 28/4 B2
Mau Than quarter (Can Tho City) and Ngo Quyen street (Lao Cai) it was
fivefold higher than permitted standard, and none of the urban centers had
dust concentration that was lower than the permitted standard.
During the period from 1995 to 1999, System of environmental monitoring stations in Vietnam measured SO2 concentration in air surrounding urban centres and industrial zones. These monitoring results were compared with the permitted standards of SO2 concentration as stipulated in the Environmental Standards of Vietnam in order to assess pollution due to SO2. In accordance to Environmental standards (TCVN) 5937-1995, the permitted standard of daily average SO2 content is 0.3mg/m3 and hourly average is 0.5mg/m.
The
environmental monitoring stations and the Environmental Situation
Report of provinces, cities and towns (in 1998-1999 as well as in
1995-1997) data showed that: in the most of urban centres in
Vietnam, both on hourly average and on daily average, SO2
concentration is lower than or approximates the permitted
standard, which means that the air environment is not yet polluted
by SO2.
In
several residential areas near industrial zones, however, some measurement
showed that SO2 concentration exceeded manifold the permitted
standard. For example, daily average concentration of SO2
(1997) reached 0.407mg/m3 (1.4 fold the permitted standard) in
residential area near Hai
Phong cement plant. In areas
near Tan Binh industrial complex (Ho Chi Minh city), SO2 concentration
exceeded by 1.1 to 2.7 fold the permitted standard.
Pollution due to CO, NO2 and O3
Environmental
standards TCVN 5937-1995 regulate permitted standards for daily average
contents of CO, NO2 and O3 gases in ambient air, as
follows: CO = 5 mg/m3, NO2 = 0.1 mg/m3
and O3 = 0.06 mg/m3.
The
measured results of National Stations of Environmental Monitoring from
1995 to 1999 show that: in large cities such as Ha Noi, Ho Chi Minh city,
Hai Phong, Da Nang, daily average content of CO gas changed from 2 to 5
mg/m3, and daily average content of NO2 gas changed
from 0.04 to 0.09 mg/m3, which were lower than permitted
standards. This means that the pollution problem due to CO an NO2
is still not serious. In some large cross-roads of several big
cities, however, contents of CO and NO2 exceed the permitted
standards. For example, in Dinh Tien Hoang-Dien Bien Phu cross-road ( Ho
Chi Minh City), the daily average value (1999) of NO2 content
was 0.255 mg/m3, which was 2.55 times the permitted standard, and CO content
was 15.46 mg/m3, which was more than three times the permitted
standard. In Da Nang steel plant area, the daily average value (1999) of
NO2 content was 0.11 mg/m3, which is 1.1 times the
permitted standard, and CO content was 12.2 mg/m3, which is
2.44 fold the permitted standard. In Thuong Dinh industrial zone (Ha Noi)
in 1999, CO content was 7.2 mg/m3 that is 1.4 times the
permitted standard; in Hai Phong cement plant in 1999, CO
concentration was 9.42
mg/m3, which is 1.88 times
the permitted standard.
Lead (Pb)
pollution in urban air
Lead
pollution in air is very dangerous to public health. Lead pollution in
urban air is generated by motor vehicles using lead-added petrol. Lead
pollution in urban air in Vietnam is not yet observed and assessed
officially by National System of Environmental Monitoring stations.
However, some local scientific centres carried out several scientific
studies of lead pollution in Ha Noi, Ho Chi Minh cities and in other urban
centres. Table 5.1 shows the observed results of these studies. According
to this Table, only in Vong crossroad, lead concentration exceeded by 1.6
times the permitted standard.
This table hereunder shows that air environment in ordinary streets is not yet polluted by lead, but lead content in air at some large cross-roads approximates or is equal to the maximum permitted standard (0.005mg/m3).
|
City
or town |
Measured
location (pollution
due to traffic) |
Lead
concentration [mg/m3] |
Data
source |
|
Ha
Noi |
Cua
Nam sixways cross-road |
0.003020 |
CEETIA,
1998 |
|
Le
Thanh Tong-Trang Thi cross-road |
0.001800 | ||
|
Trang
Tien- Hang Bai cross-road |
0.002560 | ||
|
Nga
Tu So cross-road |
0.004100 | ||
|
Nga
Tu Vong cross-road |
0.008150 | ||
|
Kim
Lien cross-road |
0.002850 | ||
|
Threeways
cross-road of highway No5 near Cau
Chui |
0.000415 | ||
|
Ha
Long |
Ha
Tu zone |
0.00270 |
Report
of Quang Ninh environmental situation |
|
Uong
Bi |
Khe
Ngat coal store |
0.00470 | |
|
Cam
Pha |
Threeway
cross-road to Vung Duc port |
0.00510 | |
|
Cua
Ong Residential area |
0.00040 | ||
|
Long
An |
Cau
Voi |
0.00500 |
CEFINA,
1998 |
|
|
Dien
Bien Phu- Dinh Tien Hoang cross-road |
0.0019-
0.0050 |
CEFINA,
1999 |
|
|
Hang
Xanh cross-road |
0.0015-
0.0043 | |
|
|
Phu
Lam cross-road |
0.0010-
0.0026 |