DRIVER GUIDE
Which limits apply to your vehicle
Enter the vehicle details. The guide shows the regulatory group from Appendix 4 and the limits in Appendices 2–3 of the Monitoring Rules.
Diesel smoke-opacity limits
An opacimeter measures two related readings: light-absorption coefficient k in m⁻¹ and light-attenuation coefficient N as a percentage. Appendix 3 to the Monitoring Rules sets the LEZ limit only in k; no separate N limit is established for the LEZ.
On smaller screens, scroll the table horizontally to view every column.
| Categories | LEZ regulatory group | Engine | Maximum k, m⁻¹ | LEZ limit for N |
|---|---|---|---|---|
| M and N | Classes 0–3 | Naturally aspirated | 2.5 | No separate LEZ limit |
| M and N | Classes 0–3 | Boosted | 3.0 | No separate LEZ limit |
| M and N | Class 4 and above | Any | 1.5 | No separate LEZ limit |
Source: Almaty city government — Vehicle Emissions Monitoring Rules, Appendix 3.
What the readings mean
- K (k)
- Light-absorption coefficient in m⁻¹. A higher k means the exhaust attenuates more light in the opacimeter. Appendix 3 uses k for the mandatory smoke-opacity limits.
- N
- Light-attenuation coefficient shown on the opacimeter’s auxiliary 0–100% scale. The LEZ has no separate N limit. For roadworthiness inspection, N is matched to k under GOST 33997-2016 using the instrument’s effective base.
A boosted engine uses a turbocharger or supercharger to supply pressurised air. If you do not know the engine type, check the model’s technical data or ask the station.
k and N describe optical smoke opacity rather than the mass of PM2.5 or PM10 particles. Compare the LEZ numerical limit specifically with k in m⁻¹.
Appendix 3 does not state a separate numerical smoke-opacity limit for category L.
A particulate filter, SCR, AdBlue and sensors are not separate universal numerical pass/fail criteria in this table. Where the vehicle was designed with this equipment, the factory system must remain complete and functional.
GOST limits for mandatory roadworthiness inspection
GOST 33997-2016 is intended for roadworthiness inspection. Where a smoke-opacity limit appears in the manufacturer’s data or the vehicle’s approval documents, that value applies. If those data are unavailable, the values below apply.
On smaller screens, scroll the table horizontally to view every column.
| Diesel vehicle group | Maximum k, m⁻¹ | Maximum N, % at L = 0.43 m |
|---|---|---|
| Environmental class 3 and below · naturally aspirated | 2.5 | 66 |
| Environmental class 3 and below · boosted | 3.0 | 72.5 |
| Environmental class 4 and above | 1.5 | 47 |
Source: KazStandard — GOST 33997-2016, clause 4.9.3 and informative Annex D.
N is the opacimeter’s auxiliary scale. These N values come from the GOST conversion table for an opacimeter with an effective base L of 0.43 m. For an instrument with a different base, N is recalculated using the standard’s formula.
This table explains roadworthiness-inspection limits under GOST. It does not create a separate LEZ limit for N.
CO and CH limits for petrol vehicles
Appendix 2 to the Monitoring Rules sets limits at minimum idle speed. For categories M and N, the applicable limit depends on the LEZ regulatory group and whether exhaust after-treatment is fitted.
On smaller screens, scroll the table horizontally to view every column.
| Vehicle and regulatory group | Condition | Maximum CO | Maximum CH |
|---|---|---|---|
| Categories M and N · classes 3, 4, 5 and 6 | Exhaust after-treatment fitted | 0.3% | 100 ppm |
| Categories M and N · classes 0, 1 and 2 | Exhaust after-treatment fitted | 0.5% | 400 ppm |
| Categories M and N · any group | No exhaust after-treatment | 3.5% | 1,200 ppm |
| Category L | No exhaust after-treatment | 4.5% | No limit stated in Appendix 2 |
Source: Almaty city government — Vehicle Emissions Monitoring Rules, Appendix 2.
What the readings mean
- CO
- Carbon monoxide. The analyser reports its volume fraction as a percentage. It is one of the two regulated readings for petrol and gas-powered vehicles.
- CH
- Unburned hydrocarbons. The analyser reports their volume fraction in parts per million (ppm). CH may be present in the exhaust provided the measured value does not exceed the applicable limit.
- O₂
- Oxygen in the exhaust, usually shown as a percentage. It helps assess mixture condition and possible air ingress, but Appendix 2 to the Monitoring Rules sets no separate LEZ limit for O₂.
- λ (lambda)
- A dimensionless excess-air ratio. A value near 1 represents a stoichiometric mixture; deviations help identify a mixture that is too lean or too rich. Appendix 2 sets no separate lambda limit.
- NO
- Nitric oxide, usually shown in ppm. It is one component of NOₓ, so an NO reading is not the same as total nitrogen oxides. Appendix 2 sets no separate NO limit.
The operator’s table shows a dash for classes 3–6, but Appendix 2 of the official Rules sets a CH limit of 100 ppm for this group. The dash must not be read as zero CH or as no CH test.
Fuel injection and exhaust after-treatment are different characteristics. The applicable row follows the presence of the designed after-treatment system, and actual measurements determine the result.
Before measurement
The Monitoring Rules set conditions that are checked before measurements begin:
- The vehicle must have travelled at least 3,000 km.
- The exhaust system must be complete, intact and leak-tight.
- The engine must be warmed to at least 60 °C according to the vehicle’s temperature gauge.
What determines compliance
A vehicle complies only when its measurements pass the applicable limit. An older vehicle can pass if its actual readings remain within the threshold for its group. Keep the electronic report showing the vehicle data, measured values and conclusion.
Fleet requirements: scope
Paragraph 40 of the city Rules applies to Almaty municipal and private fleets with diesel vehicles of environmental class 4 or higher equipped with a factory-fitted selective catalytic reduction (SCR) system. It requires reagent procurement calculated at no less than 15 litres per 1000 km per bus, with quarterly reporting. This is not a universal consumption requirement for every diesel car. Decision No. 272 provides for paragraph 40 to take effect one calendar year after the decision’s first official publication.
If the result is unsatisfactory
Confirm the measured values and identified non-compliance. Further diagnosis and repair depend on the vehicle’s condition. The station will explain the conditions for another test.
Sources and documents
Original documents are in Russian / Kazakh. English summaries are informational.
- Adilet — Vehicle emissions monitoring rules, Resolution No. 1/191 (Russian original)
- KazStandard — GOST 33997-2016: roadworthiness requirements and inspection methods (Russian original)
- UNECE — Regulation No. 24: relationship between smoke-opacity readings k and N
- Adilet — Mandatory inspection rules and intervals, Order No. 329 (Russian original)
- Adilet — Almaty Air Protection Rules, Decision No. 272 (Russian original)
- Almaty city government — vehicle emissions examination procedure from 1 September (Russian original)