What type of air is called “polluted”?

August 12, 2005
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(updated every Tuesday when data is available

Air with maximum quantity of dust particles is called polluted air. When dust particles increase, the air is more polluted. When dust particle decreases, the air is less polluted or good in quality.
What is “PM10”?
PM10 is a measurement unit for dust particles present in the air. In technical terms, PM10 means Particulate Matter with diameter less than or equal to 10 micrometer. Its measurement unit is microgram per cubic meter.

What are the types of air quality?
There are five levels of air quality depending upon the amount of dust. They are as follows:

Air Quality
Quantity of PM10 (dust)
Good
Below 60

Moderate
61 to 120

Unhealthy
121 to 350

Very Unhealthy
351 to 425

Hazardous
Above 425

Where are the air quality stations?
Air Quality of Kathmandu Valley is recorded at six stations daily, but the data is compiled on a weekly basis. The six stations are Putali Sadak, Matsyagaon, Tribhuvan University, Bhaktapur, Patan Hospital and Thamel.

Ministry of Environment and Population runs the stations under the assistance of Danish agency, Danida.

Kathmandu valley air improves                                                                  What is PM10 ?

The air quality of Kathmandu valley improved considerably from August 14 to 20 as compared to the previous period. All monitoring stations recorded a fall in pollution levels, according to the data recorded at the Ministry of Environment and Population.

The weekly averages of the air pollution levels (based on the daily averages) showed a decrease in all monitoring stations at Putalisadak, Matsyagaon, Kirtipur (Tribhuvan University area) Bhaktapur, Patan Hospital and Thamel area.

The Patan Hospital area and the Kirtipur areas were the most and least polluted sites in the Valley during the period. The Patan Hospital area recorded a weekly average of 120.57 PM10, down from the previous week’s 121.28 PM10. The area recorded ‘unhealthy’ and ‘moderate’ air marks for five and two days of the period respectively.

Weekly air quality report : Aug 14 – 20

Date
Putalisadak
Matsyagaon
Kirtipur

Bhaktapur
Patan Hospital
Thamel
2005/08/14

176

21

17

24

142

67

2005/08/15

126

10

11

23

122

46

2005/08/16

128

13

14

19

151

53

2005/08/17

155

16

15

24

131

61

2005/08/18

74

14

15

21

133

39

2005/08/19

73

13

12

31

76

49

2005/08/20

49

07

09
16

89

30

111.57
13.42
13.28
22.57
120.57
49.28
( * The Kathmandu Valley Weekly Average data is compiled by Nepalnews. Other data obtained from the Ministry of Population and Environment).

The Kirtipur area recorded ‘good’ air marks for all days of the period with a weekly average of 13.28 PM10. The Matsyagaon area was the least polluted site in the previous period with 15.71 PM10.

The Putalisadak, Thamel, and Matsyagaon area were respectively the second, third and fourth most polluted sites in the Valley during the period recording a weekly average of 111.57, 49.28 and 13.42 PM10 down from 120.28, 54.00 and 26.66 PM10 respectively.

Matsyagaon, Kirtipur and Bhaktapur areas recorded ‘good’ air marks for all days of the period.

According to the data, the overall outdoor air quality of Kathmandu valley on Tuesday (August 23) was ‘moderate’ recording 71 pgm/m3. nepalnews.com pd Aug 24 05

Valley air quality shows mixed results                                                                  What is PM10 ?

The air quality of the Kathmandu Valley, from August 07 to 13, showed mixed results as compared to the previous period, according to the data recorded by the Ministry of Environment and Population.

During the period monitoring stations recording both a rise and fall in the pollution levels while compared to the previous results.

According to the data, the weekly averages of air pollution (based on the daily average) during the period increased in Putalisadak, Kirtipur and Thamel areas while it decreased in Matsyagaon, Bhaktapur and Patan hospital areas.

Weekly air quality report : Aug 07 – 13

Date
Putalisadak
Matsyagaon
Kirtipur

Bhaktapur
Patan Hospital
Thamel
2005/08/07

76

09

N/A

16

69

40

2005/08/08

117

11

N/A

N/A

145

59

2005/08/09

134

11

N/A

26

140

49

2005/08/10

93

15

N/A

33

120

56

2005/08/11

169

24

28

47

157

61

2005/08/12

75

19

25

45

129

55

2005/08/13

178

21

27
38

89

56

120.28
15.71
26.66
34.16
121.28
54.00
( * The Kathmandu Valley Weekly Average data is compiled by Nepalnews. Other data obtained from the Ministry of Population and Environment).

As in the earlier period, the Patan hospital area was the most polluted site while the Matsyagaon area was the least polluted. The Patan hospital area recorded a weekly average (based on the daily averages) of 121.28 PM10 down from previous period’s 141.28 PM10. The area recorded ‘unhealthy’ and ‘moderate’ air marks for four and three days respectively.

The Matsyagaon area recorded ‘good’ air marks for the entire period, according to the data.

The Putalisadak, Thamel, Bhaktapur and Kirtipur area were second, third, fourth and fifth most polluted sites in the Valley. The areas recorded weekly averages of 120.28, 54, 34.16 and 26.66 PM10 respectively. The areas had, during the earlier period, recorded 108.71, 49.14 and 34.85 PM10 respectively.

The entire data of the Kirtipur area were not available.

The overall outdoor air quality of Kathmandu valley on Wednesday (August 17) was ‘moderate’ recording 61 pgm/m3.

Three-days data of Kirtipur and a day’s data of Bhaktapur areas were not available. nepalnews.com pd Aug 18 05

Valley air quality continues to show mixed results                                    What is PM10 ?

The air quality of the Kathmandu Valley, from July 31 to August 06, showed mixed results as compared to the previous period, with monitoring stations recording both a rise and fall in the pollution levels, according to the data recorded by the Ministry of Environment and Population.

According to the data, the weekly averages of air pollution (based on the daily average) during the period increased in Matsyagaon, Bhaktapur and Thamel while it decreased in Putalisadak and Patan hospital.

The Patan hospital area was the most polluted site while the Matsyagaon area was the least polluted. The Patan hospital area recorded a weekly average (based on the daily averages) of 141.28 PM10. The area recorded ‘unhealthy’ and ‘moderate’ air marks for four and three days respectively.

Weekly air quality report : July 31- Aug 06

Date
Putalisadak
Matsyagaon
Kirtipur

Bhaktapur
Patan Hospital
Thamel
2005/07/31

112

16

N/A

40

210

64

2005/08/01

103

19

28

34

209

54

2005/08/02

151

22

15

36

177

56

2005/08/03

133

17

10

38

131

54

2005/08/04

122

17

14

35

106

48

2005/08/05

90

12

08

24

79

36

2005/08/06

40

14

10
37

77

32

108.71
16.71
13.57
34.85
141.28
49.14
( * The Kathmandu Valley Weekly Average data is compiled by Nepalnews. Other data obtained from the Ministry of Population and Environment).

The Matsyagaon area recorded ‘good’ air marks for the entire period, according to the data.

The Putalisadak, Thamel and Bhaktapur area were second, third and fourth most polluted sites in the Valley. The areas recorded weekly averages of 108.71, 49.14 and 34.85 respectively. The areas had, during the earlier period, recroded a weekly average of 126.28, 48.57 and 32.71 PM10 respectively

The overall outdoor air quality of Kathmandu valley on Wednesday (July 10) was ‘good’ recording 49 pgm/m3.

The entire data of the Kirtipur area were not available.