Improved estimation of pollutant emissions from agricultural machinery and projection of its reduction potential in the Beijing-Tianjin-Hebei region, China

Abstract

As an important non-road mobile source, agricultural machinery has gradually become an important source of air pollution in China. However, research on the emission factors and mitigation potential of agricultural machinery is still in its infancy. In this study, the emission characteristics of ten common agricultural machinery in the Beijing-Tianjin-Hebei (BTH) region were measured using a portable emission measurement system (PEMS). The results show that the instantaneous emission of pollutants from agricultural machinery increased with an increase in engine power. Nitrogen oxide (NOX) emissions were 2.2 and 3.9 times higher in moving and working modes, respectively, than that in idling. The measured hydrocarbon (HC), carbon monoxide (CO), NOX, and particulate matter (PM2.5) emission factors were 0.99, 0.94, 1.12, and 0.95 times, respectively, higher than the recommended values. The CO, HC, NOX, and PM2.5 emissions from agricultural machinery in the BTH region in 2020 were 134.83, 28.54, 182.51, and 15.40 Kt, respectively. Based on the newly established inventory, four scenarios were set up to analyse the emission reduction potential. Under the integrated scenario (IS), the emission reduction potential of pollutants reaches the maximum, and the emission reduction in HC, CO, NOX, and PM2.5 in 2030 was 62.33%, 64.41%, 49.19%, and 70.94%. For single control measures, the update emission standards scenario (UES) has the best emission reduction effect of the four pollutants, the controls on in-use vehicles scenario (CIV) has the best emission reduction effect on NOX and PM2.5. These results can provide fundamental information for the development of agricultural machinery emission control policies.