Night air pollution tends to increase

Looking at the monitoring data, it can be seen that, at night, the air has been polluted but not exceeding the permitted level. However, if comparing this time with the time of 5-7 years ago, the pollution of daytime and nighttime is increasing.

Do not exclude the possibility of exceeding the allowable level

MS Bui Hoai Thanh, Head of Environment Department, Center for Meteorological, Hydrological and Environmental Network, said that looking at the observed data, it can be seen that at night, the air shows signs of pollution but not over permitted levels. Specifically, according to the average standard TSP is 300mg / m ³ / h and 200mg / m ³ / 24h; PM10 is 150mg / m ³ / 24h (PM 10 does not have an hourly standard).

With this standard, for PM10, not only at night, but even during the day and not exceeding the permitted threshold, for example on November 23, is 83mg / m ³ , on November 6 is 123mg / m ³ . There are also surpassing days like November 18 as 195. However, the days beyond are not much.

The night air has a contaminated expression.

For TSP, if calculated by day, most of them overtake the example of November 23 as 237mg / m ³ , November 18 is 241 . However, if compared to the hour, the night time TSP is not beyond the permitted level, the main hours in the night are only below 200 (the norm is 300mg / m ³ / h).

According to MSc Bui Xuan Thanh, until now, there has not been any specific study of night air quality. However, the monitoring results show that the night air has been contaminated but has not exceeded the permitted level. However, if comparing this time with the time of 5-7 years ago, the pollution of daytime and night time tends to increase. Currently not worrying. But at the current rate, the future will not rule out the possibility of exceeding the allowable level.

Monitoring is just a corner of pollution

From the air monitoring data, we returned to learn the process of gas sampling and collect the measurement results of Lang monitoring station (Hanoi). The station was located in the middle of the residential area, with little smoke and dust, but the amount of dust measured at the time we arrived was not small.

The observer Nguyen Lan Huong said that the parameters shown on the monitoring machine on December 3 are as follows: At 14:51, the humidity is only 47%. This is quite low humidity because it is the middle of winter. TSP at this time is 144, PM10 is 41, while according to our observation here the weather is nice, around the station many trees and almost no dust visible.

On the indicator board, the SO _{2 content} is 672 (while the standard is 350). However, this is just an instant value, updated every minute and will be aggregated at the end of the day and at the end of the day . These measured data will be gathered into the archive and transferred to the analysis center. . For discontinuous index times, employees will have to rely on the previous data and then to estimate the most approximate numbers.

According to Mr. Nguyen Nhat Anh, team of Air Environment, Environment Department, Center for Meteorological and Environmental Hydrological Network, if measuring in other locations such as roads with large traffic volume, where there are many construction works, factories of processing enterprises . surely the measurement will exceed the threshold. PM10 dust does not change the value of many measurements due to its large dispersion ability.

Sometimes the house is closed, but this dust is still abundant. Night dust is not visible much, but in reality it is still dangerous and threatening health if exposed to a lot of environment.