The Paradox of 2025: Official Data Shows Lower Average Pollution Levels in Almaty, Yet Episodes of Heavy Smog Persist

Almaty Air Initiative reviewed the raw data and annual reports published by the national monitoring agency to understand how it assessed air quality in Almaty in 2025.

The full report and Kazhydromet’s data visualizations are available here.

According to Kazhydromet’s 2025 report, Almaty’s average background pollution level decreased by 31%. The Air Pollution Index (API) was 4, compared with 5.8 in 2024, officially placing the city in the “low pollution” category.

The decline in the Air Pollution Index (API) is likely associated with lower average daily concentrations of major pollutants compared with the previous year: nitrogen dioxide (−25%), carbon monoxide (−34%), and sulfur dioxide (−37%). The sharpest decrease was recorded for ozone, from 1.3 to 0.2, representing a reduction of more than sixfold.

At the same time, the report notes that 88% of the city’s enterprises lack pollution control facilities, while the vehicle fleet increased by 41,000 vehicles over the year. There have also been no significant changes in major emission sources over the past year. For example, CHP-2 and CHP-3 are still undergoing conversion to natural gas.

Furthermore, such an improvement in air quality is difficult to explain by weather conditions. According to Kazhydromet, 2025 was drier than 2024, and reduced precipitation generally limits the atmosphere’s natural cleansing processes.

Why, then, do the national monitoring agency’s data indicate an improvement? One possible explanation lies in the measurement methods and data processing methodology.

To assess overall background pollution, Kazhydromet uses the Air Pollution Index (API). This composite indicator reflects annual average air pollution levels across a group of priority pollutants, taking into account their concentrations relative to established permissible limits and their hazard classifications.

Other indicators are also used to provide a more complete picture:

• SI (Standard Index) reflects the most severe pollution episode and indicates how many times the maximum recorded concentration exceeded the established limit.
• HF (Highest Frequency of Exceedance) indicates how frequently pollutant concentrations exceeded permissible levels.

According to these two indicators, the city’s air pollution level is classified as high.

The most severe pollution episode (SI) in 2025 was associated with nitrogen oxides. While short-term concentrations of this pollutant exceeded the limit by approximately 2.5 times in 2024, maximum values in 2025 reached almost 10 times the permissible level.

Regarding the Highest Frequency of Exceedance (HF), which reflects how often pollutant concentrations exceed permissible levels, the following changes were recorded in Almaty in 2025:

• The number of exceedances for carbon monoxide (CO) decreased almost fivefold.
• Exceedances for suspended particles (dust) decreased by more than half, while those for PM2.5 decreased approximately 1.5-fold.
• The sharpest change was observed for ozone: the number of exceedances fell from 8,036 to 77 cases, a reduction of more than 100 times.

At the same time, the number of exceedances for nitrogen monoxide (NO) increased approximately 1.5-fold. Figures for nitrogen dioxide (NO₂) and sulfur dioxide (SO₂) were comparable to those recorded in the previous year.

A comparative table is provided below for reference.

Table. Comparison of the Number of Exceedances of the Maximum Single-Exposure Permissible Concentration (2024–2025)

Why Some Locations in Almaty Show Lower Pollution Levels Than an Oceanic Island

What the analysis of Kazhydromet’s raw data for 2025 revealed.

In addition to reviewing the summary data presented in Kazhydromet’s annual report, we conducted an independent analysis of the raw air quality measurements for 2025. These data were obtained directly from the agency through an official request.

According to official information, Almaty has 16 monitoring posts: 12 automated stations that take continuous measurements every 20 minutes and four manual sampling posts that collect three samples per day.

The analysis produced the following findings:

• Zero values and anomalous spikes. The analysis revealed that some stations reported annual average concentrations of 0.00 µg/m³ or less than 2 µg/m³. Rather than indicating an absence of pollution, these values may point to analyzer malfunctions, extended equipment downtime, or technical issues with data exports. Time series from certain monitoring posts (for example, Post No. 5 near Halyk Arena) show unusual patterns: consistently low readings for six months followed by sharp, unexplained spikes toward the end of the year.

Such patterns contradict years of independent observations and findings reported in scientific literature.

• Monitoring coverage. The coverage analysis showed that some stations had low data completeness (less than 50% of the year), making the resulting average concentration estimates unrepresentative.
• Geographical distortion of indicators (the Skat-2 case). One of the automated stations, Skat-2, is located outside Almaty’s administrative boundaries. Including its measurements in citywide calculations distorts the actual pollution picture because the station records background conditions outside the city, which may differ from smog levels in urban areas.
• Ozone (O₃) concentrations showed the largest decline in annual average values (sixfold), while the number of exceedances decreased more than 100-fold.
• One possible explanation is that nine of the 12 automated stations reported readings close to zero. Similar patterns were observed for several other pollutants. The chart below illustrates the dynamics of average daily concentrations of major pollutants across all stations in Kazhydromet’s monitoring network in 2025.
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• Manual data collection. Official calculations often rely on measurements from manual monitoring posts, where samples are collected only three times per day. This approach can miss short but potentially dangerous nighttime and morning emission spikes that automated stations, operating every 20 minutes, are capable of detecting.

Is Almaty “Cleaner” Than an Oceanic Island?

Given the concerns about data quality and completeness outlined above, there is a risk of a so-called “averaging effect”: the overall citywide indicator may appear lower than actual pollution levels because measurements from instruments producing unstable data are included in the calculations. Excluding such measurements could result in higher estimated average pollutant concentrations. Let us consider PM2.5 as an example.

• The chart of annual average PM2.5 concentrations for 2025 shows substantial differences between Kazhydromet stations. Some monitoring posts report values below 1 µg/m³ (!), while others reach 43.6 µg/m³ (Station 28). The Skat-6 station reports 32.2 µg/m³, a level comparable to the annual average PM2.5 concentration reported by Almaty Air Initiative (AAI) for 2025. Meanwhile, some stations report significantly lower values, and data are entirely missing from several monitoring posts.
• The citywide indicator is calculated as an average across the entire network of automated stations. If some stations recorded nearly constant values close to zero or concentrations below 1 µg/m³ throughout the year, this would automatically lower the final citywide average, as reflected in the annual bulletin.

Such patterns may be associated with analyzer performance, equipment calibration, prolonged technical interruptions, incorrect signal recording, or data processing methods. Under international standards (WHO, ISO), such data should be excluded from average calculations.

• In a large city with heavy traffic and a heating season, annual PM2.5 concentrations below 1 µg/m³ appear unusual for Almaty compared with other available data and may require additional technical verification. For comparison, according to IQAir reports for 2024–2025, even the cleanest locations on the planet record concentrations above 1 µg/m³. For example, Mayagüez, Puerto Rico, an island city exposed to ocean winds, has an average concentration of 1.1 µg/m³.

Annual Average Concentrations by District

• An analysis of data from 12 automated stations revealed significant variations in air quality across different parts of the city. Pollution is unevenly distributed, reflecting the influence of local emission sources, from major roads to industrial areas.
• Differences in gaseous pollutant concentrations are substantial. The highest carbon monoxide (CO) levels were recorded in the Alatau and Medeu districts (approximately 714 and 550 µg/m³, respectively), while the lowest levels were observed in the Turksib district (approximately 181 µg/m³). However, according to Almaty Air Initiative data, the Turksib and Alatau districts have some of the highest PM2.5 concentrations. For nitrogen dioxide (NO₂), the highest concentrations were recorded near the Burunday Motor Depot and in the Zhetysu district (approximately 92–94 µg/m³).
• Differences in PM2.5 concentrations are less pronounced but remain consistent. Annual average PM2.5 concentrations range from 1.4 µg/m³ in the Alatau district to 17 µg/m³ in the Turksib district and 32 µg/m³ in the Zhetysu district. Maximum PM10 concentrations reach 39 µg/m³, while minimum values are around 1.5 µg/m³.

When comparing Kazhydromet’s data with Almaty Air Initiative’s (AAI) 2025 PM2.5 report, significant discrepancies emerge.

Key Findings from the Comparison:

• While Kazhydromet reports a downward trend in average background pollution, AAI data indicate that pollution levels have remained high or even increased (by 30% compared with 2024). One possible explanation for the discrepancy is differences in the density and structure of the monitoring networks, the stations included, data completeness, and aggregation methods, all of which affect the resulting annual averages.
• Both sources confirm that the Turksib district is an area with a high pollution burden. However, their estimates differ: 17.0 µg/m³ according to Kazhydromet versus 46.8 µg/m³ according to AAI. Kazhydromet’s figure is comparable to levels in several European capitals, while AAI’s value reflects higher pollution concentrations captured by its dense sensor network.

The discrepancy may also be explained by station density and placement: AAI’s network includes more measurement points and is not limited to locations with more favorable air circulation.

• The substantial discrepancy in the Alatau district (1.4 versus 37.7 µg/m³) is likely associated with technical factors affecting stations in the national monitoring network, such as analyzer malfunctions or calibration issues. A concentration of 1.4 µg/m³ appears unusually low for an urban district and requires additional verification. For comparison, values around 1 µg/m³ are characteristic of remote, sparsely urbanized areas, such as oceanic islands.

In the Alatau district, where traffic, urban development, and solid-fuel heating are present, such a low value appears atypical. By contrast, the AAI figure of 37.7 µg/m³ is consistent with levels observed in major cities with complex terrain and widespread solid-fuel heating.

These findings highlight the importance of combining monitoring approaches: government stations provide certified measurements, while community-based networks offer denser coverage across the city. This allows cross-validation between networks and data sources, giving the city a more complete and accurate picture of air pollution.

Who Pollutes the Air According to Kazhydromet?

• Stationary sources. Kazhydromet’s report notes that, among approximately 9,000 stationary emission sources in the city, 88% of enterprises are not equipped with pollution control facilities. This points to a systemic problem with industrial emission filtration. However, the report does not estimate the total volume of pollution generated by these enterprises, making it difficult to assess their actual contribution to overall air pollution.
• Private households. The report also states that 98.8% of residential buildings are connected to natural gas. However, this calculation may not fully account for properties in informal settlements, temporary structures, and private bathhouses, where coal or other fuels may still be used for heating. In addition, the analysis provides limited consideration of the wider Almaty metropolitan area, where air currents can transport emissions from suburban settlements into the city’s basin.
• Road transport. The report records an increase in the vehicle fleet to 643,000 vehicles (+41,000 over the year). At the same time, the number of exceedances increased for nitrogen monoxide (+50.2%) and nitrogen dioxide (+11.6%). However, the report does not provide an assessment of each emission source’s contribution to overall pollution levels.

From Data to Action: How Can Air Quality Monitoring Become More Reliable?

Almaty Air Initiative notes that the current data situation may pose reputational risks for the national monitoring agency and complicate evidence-based decision-making by city authorities. The foundation therefore proposes focusing on constructive cooperation.

Conducting a Joint Technical Audit

We propose that Kazhydromet establish a joint field inspection team to visit monitoring locations with the most anomalous readings (the Alatau district and Post No. 5). The aim would be to conduct parallel measurements using reference-grade equipment and independent sensors to verify whether the stations are operating correctly.

Introducing a Data Transparency Protocol

• Publish not only averaged figures but also the operational uptime of each station, along with more detailed analyses of daily and seasonal pollution patterns.
• Develop protocols and introduce an automated system for excluding “technical zeros” and anomalous spikes from final statistics.

Creating a Hybrid Monitoring System

We propose discussing a mechanism for integrating data from independent monitoring networks into government analyses. This would help identify blind spots in areas where Kazhydromet has no stations and create a denser, more reliable map of air pollution across Almaty.

Almaty Air Initiative is ready to provide a comprehensive diagnostic assessment of all stations in Kazhydromet’s monitoring network to identify anomalies and technical malfunctions and support further joint work.