How to Calculate Actual VOCs Emissions apply to RTO System

2025-09-11

Quantification of VOCs Pollution
Quantifying VOC pollution is the first step when preparing a VOCs control plan. In daily work, this can be accomplished either through on-site measurement or material balance calculation, based on environmental impact assessment (EIA) data.

Determining the VOCs concentration is essential for selecting the appropriate treatment technology. I've included the following content for you to look over.

I. Calculation Methods and Priority

Calculation Methods for Exhaust Gas (Containing VOCs) Pollution
The priority order of methods is: automatic monitoring method > manual monitoring method > emission factor method. Calculation formulas are shown in Formula (1), Formula (2), and Formula (3).
According to Article 36 of the “Measures for the Administration of Discharge Permits (Trial)”:
The actual emission of pollutants shall be calculated separately for exhaust gas and wastewater discharge outlets, production facilities, or workshops as specified in the discharge permit, following the methods and order below:

(1) For facilities legally equipped with pollutant automatic monitoring devices that meet national regulations and monitoring standards, calculate emissions based on automatic monitoring data.
(2) For facilities legally not required to install automatic monitoring devices, calculate emissions based on manual monitoring data that comply with national regulations and monitoring standards.
(3) For cases where the above methods cannot be applied, including facilities legally required to install automatic monitoring devices but not installed, or automatic monitoring devices that do not meet requirements, calculate emissions according to emission factors or material balance methods as prescribed by the Ministry of Ecology and Environment.

II. Calculation Formulas

01. Automatic Monitoring Method

E=Q×C×T×10−9E = Q \times C \times T \times 10^{-9}E=Q×C×T×10−9

Formula (1)

Where:

EEE — actual pollutant emissions during a period, t;
QQQ — flue gas flow rate (average value if multiple measurements in the period), m³/h;
CCC — pollutant concentration (average value if multiple measurements in the period), mg/m³;
TTT — pollutant emission duration during the period, h.

02. Manual Monitoring Method

E=V×T×10−3E = V \times T \times 10^{-3}E=V×T×10−3

Formula (2)

Where:

EEE — actual pollutant emissions during a period, t;
VVV — emission rate (average value if multiple measurements in the period), kg/h;
TTT — pollutant emission duration during the period, h.

03. Emission Factor Method

E=A×α×B×(1−C)×10−3E = A \times \alpha \times B \times (1-C) \times 10^{-3}E=A×α×B×(1−C)×10−3

Formula (3)

Where:

EEE — actual pollutant emissions during a period, t;
AAA — product output or raw/auxiliary material consumption during the period, t;
α\alphaα — pollutant generation coefficient, kg/t-product or raw/auxiliary material;
BBB — exhaust gas collection efficiency, %;
CCC — removal efficiency of the pollutant, %.