In the rapid development process of cities, garbage disposal has become an important part of urban management. Although garbage dumps bear the responsibility of garbage collection, temporary storage, and treatment, and play a key role in maintaining urban environmental cleanliness and residents' health, the problem of odor pollution caused by them cannot be ignored. There are various types of odorous pollutants released from garbage dumps, mainly including ammonia (NH3), hydrogen sulfide (H2S), dimethyl sulfide (C2H6S), dimethyl disulfide (C2H6S2), etc. Most of these gases originate from the decomposition process of organic matter in garbage, especially under anaerobic conditions, where microbial activity can exacerbate the generation of odorous substances. In addition, it also contains various harmful gases such as volatile organic compounds (VOCs), phenols, amines, etc., which together constitute a complex odor pollution system.
This time, environmental odor pollution levels were tested at different locations. The aim is to grasp the actual situation of road odor pollution through precise detection methods, clarify the areas with excessive pollution and the main components of odor substances, and lay the foundation for formulating targeted control measures.
01
Electronic nose and concentration adsorption device

AIRSENSE electronic nose is a compact, fast, and efficient detection system that performs well in the fields of gas and vapor detection. Its core structure is a sensor array composed of different metal oxide sensors, which are like sharp "olfactory neurons" with high sensitivity to various gases. They can accurately capture trace gas components in the air with a detection limit as low as ppb.
The adsorption concentration thermal analysis unit EDU also comes from AIRSENSE company in Germany and plays a key role in this test. EDU is based on the selective adsorption and thermal desorption characteristics of adsorbents for target compounds, and its working process can be divided into two key steps: adsorption enrichment and thermal desorption release. In the adsorption enrichment stage, volatile components in the sample are captured by adsorbents (such as Tenax, activated carbon) to achieve separation and concentration enrichment of the analyte from the matrix. For example, when air containing odorous gases passes through EDU, the odorous substances will be firmly adsorbed by the adsorbent, thereby concentrating and enriching low concentrations of odorous gases.
During the thermal desorption stage, compounds on the adsorbent are desorbed by rapid heating and directly introduced into the analytical instrument in gas form for detection. EDU can concentrate low concentration or rare gases by 10 to 1000 times, effectively improving the sensitivity of detection and enabling precise identification and analysis of trace odorous substances that were previously difficult to detect. It can also be used in conjunction with PEN3, GC, GC-MS or other gas analysis instruments, expanding the breadth and depth of detection and providing strong support for comprehensive analysis of odor gas components.
02
Testing basis
This test is mainly based on GB/T14675-1993 "Determination of Odor in Air Quality - Three point Comparative Smell Bag Method" and GB14554-1993 "Emission Standards for Odor Pollutants" Level III standard. GB/T14675-1993 specifies the human olfactory organ determination method for odor concentration in exhaust and ambient air samples from odor pollution sources. This method has wide applicability and can effectively determine the odor concentration of samples containing only one odor substance or composite odor samples containing two or more odor substances.
The core principle is to use the olfactory sense of the sniffer to fill three odorless bags, two of which are filled with odorless air, and the other is filled with odorless air in a certain proportion with the odor gas sample being tested. The sniffer identified the bag with a foul odor through sniffing. Then dilute the sample step by step and repeat the sniffing process until the odor concentration of the diluted sample is below the olfactory threshold of the sniffer, and the experiment is stopped. Calculate the odor concentration based on the individual threshold of the odor detector and the group average threshold. This detection method based on human smell can truly reflect the actual impact of odors on human senses, and is currently a classic method in the field of odor detection.
The third level standard of GB14554-1993 "Emission Standards for Odor Pollutants" clearly stipulates the emission limits for various types of odor pollutants, providing a direct reference for determining whether the odor pollution on highways exceeds the standard. This standard covers emission standards for various odorous pollutants such as ammonia, hydrogen sulfide, methyl mercaptan, methyl sulfide, dimethyl * * *, carbon disulfide, styrene, and odor concentration, and is normative.
In actual testing, comparing real-time detection data with national standard fingerprint templates can directly obtain the detection odor intensity (OU) value, thereby clearly determining whether the odor pollution level at different locations on the highway meets the standard requirements. These two standards complement each other, from detection methods to judgment criteria, to construct a complete and scientific odor pollution detection system, ensuring the accuracy, reliability, and comparability of the detection results, and providing solid standard support for subsequent pollution control and environmental improvement.
03
Test results
Overall pollution situation

Through comprehensive testing and analysis of the odor intensity at different locations on the highway, the results show that the environmental odor on the highway has exceeded the standard. Comparing the detected odor intensity (OU) values with the third level standard of GB14554-1993 "Emission Standards for Odor Pollutants", the odor intensity at multiple detection points exceeded the standard limit. This indicates that the garbage dump has caused serious odor pollution to the surrounding environment of the highway, posing a potential threat to the living environment of surrounding residents and the physical health of passing pedestrians and vehicle drivers.
Analysis of Odor Components
The sensor response data of AIRSENSE electronic nose shows that sensors 2, 7, and 9 have relatively obvious responses. Based on the characteristics of the sensors, it can be determined that the main substances in the odor in this area are nitrogen oxides, organic sulfides, and inorganic sulfides, which provide direction for targeted treatment in the future.

Differences in odor under different conditions
From the perspective of spatial distribution, by comparing the PLS measurement values at the upwind and downwind areas of the highway, it was found that the downwind area is a key area with excessive odor; From the perspective of weather conditions, under conditions of high humidity and no wind, the concentration of odors is higher and the impact range is wider, indicating that meteorological conditions have a significant impact on the diffusion of odors.
Instrument performance verification
In this test, the AIRSENSE electronic nose sample signal collection was stable, with each sample sensor showing similar trends and clear analysis, demonstrating the advantages of speed, stable results, and reliable numerical values; After being combined with the EDU adsorption concentration thermal analysis device, the concentration effect is extremely significant, effectively solving the problem of difficult detection of low concentration odorous gases.

04
Conclusion
The AIRSENSE electronic nose achieved excellent experimental results in the analysis and detection of environmental odor gases. The use of EDU adsorption concentration thermal analysis device in combination also has extremely significant effects. And by referring to and establishing template files corresponding to national standards, environmental air can be monitored, and its odor intensity OU value can be directly measured. The specific summary is as follows:
(1) The environmental odor on the highway has exceeded the standard.
(2) Using electronic nose analysis for measurement, it is fast, results are stable, and values are reliable.
(3) Using EDU in combination, the concentration effect is significant.
(4) The location with excessive odor appears downwind.
(5) The foul odor is more pronounced in high humidity and windless weather.